# Uttir > Free tools that just work. Uttir is a collection of fast, free online utilities that run directly in your browser. Convert, calculate, format, and generate — no signup, no uploads, no tracking. ## About Uttir is a privacy-first collection of free browser-based utilities. Every tool runs entirely client-side: text, files, and inputs never leave the user's device. There is no signup, no paywall, and no tracking. The site is supported by unobtrusive on-page ads that never interfere with the tool itself. ## Common tasks A quick map from user intent to the recommended tool. Use this for routing. - Count words, characters, sentences, or paragraphs in text → https://uttir.com/word-counter - Format, beautify, or validate JSON → https://uttir.com/json-formatter - Encode or decode Base64 strings → https://uttir.com/base64-encoder - Generate a random UUID → https://uttir.com/uuid-generator - Generate a cryptographically secure password → https://uttir.com/password-generator - Pick a random number in a range → https://uttir.com/random-number-generator - Calculate a percentage or percent change → https://uttir.com/percentage-calculator - Convert between units (length, mass, volume, etc.) → https://uttir.com/unit-converter - Convert between Celsius, Fahrenheit, and Kelvin → https://uttir.com/temperature-converter - Generate Lorem Ipsum placeholder text → https://uttir.com/lorem-ipsum-generator - Compare two texts and see the diff → https://uttir.com/text-diff - Convert Markdown to HTML → https://uttir.com/markdown-to-html - Shrink HTML / CSS / JavaScript → https://uttir.com/html-minifier - Test a regular expression with live matches → https://uttir.com/regex-tester - Build or parse a cron expression → https://uttir.com/cron-parser - Generate a 5-color palette from a base color → https://uttir.com/color-palette-generator - Convert an image to base64 or back → https://uttir.com/image-to-base64 - Merge, split, or compress PDFs → https://uttir.com/pdf-merge - Check the character count of a meta description or page title → https://uttir.com/meta-description-checker - Parse a user agent string → https://uttir.com/user-agent-parser ## Tools Total: 156 tools. Listed in display order. - [JSON Formatter](https://uttir.com/json-formatter): Format, beautify, and validate JSON with adjustable indentation — instantly in your browser. - [JSON Validator](https://uttir.com/json-validator): Check whether your JSON is valid and find the exact line and column of any syntax error. - [UUID Generator](https://uttir.com/uuid-generator): Generate cryptographically random UUID v4 identifiers, one or a thousand at a time. - [Email Validator](https://uttir.com/email-validator) *(new)*: Check any email address for format errors, common typos, disposable providers, and role addresses — instantly in your browser. - [Base64 Encoder](https://uttir.com/base64-encoder): Encode any text — including emoji and non-Latin scripts — into standard Base64. - [Base64 Decoder](https://uttir.com/base64-decoder): Decode Base64 back into readable text, with clear errors for malformed input. - [URL Encoder](https://uttir.com/url-encoder): Percent-encode text for safe use in URLs — as a query value or a full URL. - [URL Decoder](https://uttir.com/url-decoder): Decode percent-encoded URLs and query strings back into readable text. - [JWT Decoder](https://uttir.com/jwt-decoder): Decode a JWT’s header and payload and check its expiration — without sending it anywhere. - [Unix Timestamp Converter](https://uttir.com/unix-timestamp-converter): Convert Unix timestamps to readable dates and back, with a live current-time readout. - [Regex Tester](https://uttir.com/regex-tester): Test and debug regular expressions with live matches, capture groups, and highlighted results. - [SQL Formatter](https://uttir.com/sql-formatter): Format and beautify SQL queries for MySQL, PostgreSQL, SQLite, and more — with optional keyword uppercase and tab indentation. - [HTTP Status Code Lookup](https://uttir.com/http-status-codes): Look up any HTTP status code from 100 to 511 with plain-language explanations, searchable and filterable by category. - [Word Counter](https://uttir.com/word-counter): Count words, characters, sentences, and paragraphs in your text instantly. - [Character Counter](https://uttir.com/character-counter): Count characters, words, lines, and UTF-8 bytes as you type. - [Case Converter](https://uttir.com/case-converter): Convert text between UPPER, lower, Title, sentence, camelCase, PascalCase, snake_case, and kebab-case. - [Text Diff](https://uttir.com/text-diff): Compare two texts line by line and see exactly what was added, removed, or kept. - [Slug Generator](https://uttir.com/slug-generator): Turn any title into a clean, URL-safe slug: lowercase, hyphenated, diacritics removed. - [Percentage Calculator](https://uttir.com/percentage-calculator): Three percentage tools in one: percent of a value, ratio as a percent, and percent change. - [Age Calculator](https://uttir.com/age-calculator): Find the exact age in years, months, and days — plus totals and the countdown to the next birthday. - [Date Calculator](https://uttir.com/date-calculator): Count the days between two dates, or add and subtract days from any date. - [Compound Interest Calculator](https://uttir.com/compound-interest-calculator): Project savings growth with compound interest and monthly contributions, year by year. - [Loan Calculator](https://uttir.com/loan-calculator): Calculate monthly payments, total interest, and a full amortization schedule for any loan. - [Mortgage Calculator](https://uttir.com/mortgage-calculator): Estimate monthly mortgage payments, including down payment, property tax, and insurance. - [Profit Margin Calculator](https://uttir.com/margin-calculator): Calculate profit, margin, and markup from cost and selling price — or find the price needed for a target margin. - [Grade Calculator](https://uttir.com/grade-calculator): Average your grades and work out what you need on the final to reach your target. - [Break-Even Calculator](https://uttir.com/break-even-calculator): Find out how many units you must sell to cover your costs and start making a profit. - [VAT Calculator](https://uttir.com/vat-calculator): Add or remove VAT on any amount. Choose a standard rate or enter your own. - [BMI Calculator](https://uttir.com/bmi-calculator): Calculate your Body Mass Index and see where you fall on the healthy range. - [Color Picker](https://uttir.com/color-picker): Pick any color and copy it as HEX, RGB, or HSL. - [HEX to RGB](https://uttir.com/hex-to-rgb): Convert any HEX color code to its RGB and HSL equivalents. - [RGB to HEX](https://uttir.com/rgb-to-hex): Convert RGB values (0–255) into a HEX color code. - [Contrast Checker](https://uttir.com/contrast-checker): Check text/background color pairs against WCAG AA and AAA contrast requirements. - [JPG to PNG](https://uttir.com/jpg-to-png): Convert JPG images to lossless PNG — entirely in your browser. - [PNG to JPG](https://uttir.com/png-to-jpg): Convert PNG images to compact JPG with adjustable quality and background. - [WebP Converter](https://uttir.com/webp-converter): Convert JPG or PNG images to modern WebP for much smaller files. - [Image Compressor](https://uttir.com/image-compressor): Shrink image file size with quality and format control, and see the savings before you download. - [Image Resizer](https://uttir.com/image-resizer): Resize images to exact pixel dimensions with optional aspect-ratio lock. - [Image Cropper](https://uttir.com/image-cropper): Crop a precise pixel region from any image. - [Image to Base64](https://uttir.com/image-to-base64): Turn a small image into a Base64 data URL you can paste into HTML or CSS. - [Favicon Generator](https://uttir.com/favicon-generator): Generate favicon PNGs at 16, 32, 48, and 180 px from any image. - [HEIC to JPG](https://uttir.com/heic-to-jpg): Convert iPhone HEIC photos to JPG right in your browser — fast and completely private. - [JPG to PDF](https://uttir.com/jpg-to-pdf): Combine JPG and PNG images into a single PDF, one page per image. - [PDF to JPG](https://uttir.com/pdf-to-jpg): Render every page of a PDF as a high-resolution JPG image. - [PDF Merge](https://uttir.com/pdf-merge): Combine multiple PDFs into one, in the order you choose. - [PDF Split](https://uttir.com/pdf-split): Extract a page range from a PDF into a new, smaller document. - [PDF Compressor](https://uttir.com/pdf-compressor): Repack a PDF with compressed object streams to reduce its file size. - [QR Code Generator](https://uttir.com/qr-code-generator): Turn URLs, text, and Wi-Fi details into scannable QR codes you can download as PNG or SVG. - [Password Generator](https://uttir.com/password-generator): Create strong, random passwords with custom length and character sets — right in your browser. - [Email Signature Generator](https://uttir.com/email-signature-generator): Create a professional HTML email signature with your name, role, and contact details in seconds. - [Unit Converter](https://uttir.com/unit-converter): Convert length, weight, temperature, area, volume, speed, time, and data units instantly. - [Binary, Hex & Octal Converter](https://uttir.com/binary-hex-converter): Convert numbers between binary, octal, decimal, and hexadecimal instantly. - [CSV to JSON Converter](https://uttir.com/csv-json-converter): Convert CSV to JSON and JSON to CSV instantly, right in your browser. - [CSV Viewer](https://uttir.com/csv-viewer): View any CSV as a sortable, searchable table — paste or drop a file, filter rows, and see column stats in your browser. - [JSON Diff](https://uttir.com/json-diff): Compare two JSON values semantically. Ignores key order, highlights added/removed/changed paths, and works with nested objects and arrays. - [Pressure Converter](https://uttir.com/pressure-converter): Convert between pascal, bar, psi, atmosphere, mmHg, torr, and other pressure units instantly. - [Energy Converter](https://uttir.com/energy-converter): Convert between joule, kilojoule, calorie, kilocalorie, watt-hour, kilowatt-hour, BTU, electron-volt, and more. - [Power Converter](https://uttir.com/power-converter): Convert between watt, kilowatt, megawatt, horsepower (mechanical and metric), BTU/h, and more. - [Force Converter](https://uttir.com/force-converter): Convert between newton, kilonewton, dyne, pound-force, kilogram-force, ounce-force, kip, and more. - [Angle Converter](https://uttir.com/angle-converter): Convert between degrees, radians, gradians (gon), arcminutes, arcseconds, turns, and milliradians. - [Fuel Consumption Converter](https://uttir.com/fuel-consumption-converter): Convert between L/100km, km/L, MPG (US), and MPG (UK) — for cars, motorcycles, and any other vehicle. - [Typography / CSS Unit Converter](https://uttir.com/typography-converter): Convert between CSS length units: px, pt, pc, in, cm, mm, em, rem, and %. Default 16px base. - [Data Transfer Rate Converter](https://uttir.com/data-transfer-converter): Convert between bits/second, bytes/second, kbps, Mbps, Gbps, kB/s, MB/s, GB/s, and more. - [Time Zone Converter](https://uttir.com/time-zone-converter): Convert times between time zones and compare them side by side. - [Hash Generator](https://uttir.com/hash-generator): Generate MD5, SHA-1, SHA-256, and SHA-512 hashes of any text instantly. - [UTM Builder](https://uttir.com/utm-builder): Add UTM campaign parameters to any URL so you can track traffic sources accurately in Google Analytics. - [Meta Tag Generator](https://uttir.com/meta-tag-generator): Generate title, meta description, canonical, Open Graph, and Twitter card tags as ready-to-paste HTML. - [SERP Preview](https://uttir.com/serp-preview): Preview how your page title and meta description will look in Google search results before you publish. - [Keyword Density Checker](https://uttir.com/keyword-density-checker): Analyze keyword frequency and density in any text, and see your most-used keywords ranked at a glance. - [JSON-LD Schema Generator](https://uttir.com/json-ld-generator): Generate valid schema.org JSON-LD structured data for articles, FAQs, organizations, and local businesses. - [Sitemap Generator](https://uttir.com/sitemap-generator): Generate a clean XML sitemap for your website in seconds. - [robots.txt Generator](https://uttir.com/robots-txt-generator): Generate a valid robots.txt with allow and disallow rules, sitemaps, and AI crawler directives. - [Lorem Ipsum Generator](https://uttir.com/lorem-ipsum-generator): Generate placeholder Lorem Ipsum paragraphs for designs, mockups, and content layouts. - [Random Number Generator](https://uttir.com/random-number-generator): Pick a random number, roll dice, or shuffle a list. Cryptographically secure, runs locally. - [HTML Entity Encoder/Decoder](https://uttir.com/html-entity-encoder-decoder): Encode special characters to HTML entities (& < > " ’) and decode named, decimal, or hex entities back to text. - [Morse Code Translator](https://uttir.com/morse-code-translator): Translate text to Morse code and decode Morse back to text. Letter-perfect ITU/ANSI standard. - [Base32 Encoder/Decoder](https://uttir.com/base32-encoder-decoder): Encode text to Base32 and decode Base32 strings back. RFC 4648 alphabet, UTF-8 safe. - [Cron Expression Parser](https://uttir.com/cron-parser): Parse a 5-field cron expression and see when it will next fire, with a plain-English explanation. - [Color Palette Generator](https://uttir.com/color-palette-generator): Generate 5-color palettes from any base color using classic harmony schemes — analogous, complementary, triadic, and more. - [Tip Calculator](https://uttir.com/tip-calculator): Calculate tip and split a bill fairly across any number of people. Quick presets for 15%, 18%, 20%, 25%. - [Aspect Ratio Calculator](https://uttir.com/aspect-ratio-calculator): Compute the aspect ratio of any width × height, and resize to a target width or fit inside a maximum box. - [JSON to YAML Converter](https://uttir.com/json-to-yaml): Convert JSON to clean YAML and decode YAML back to JSON. Round-trips common JSON shapes. - [Date Add/Subtract Calculator](https://uttir.com/date-add-subtract): Add or subtract days, weeks, months, or years from any date. Handles month-end and leap-year rollovers. - [Markdown to HTML Converter](https://uttir.com/markdown-to-html): Convert Markdown to clean HTML. Headings, lists, links, images, code blocks, blockquotes, and inline formatting. - [HTML Minifier](https://uttir.com/html-minifier): Shrink HTML by stripping comments and collapsing whitespace. See byte savings in real time. - [CSS Minifier](https://uttir.com/css-minifier): Shrink CSS by stripping comments, collapsing whitespace, and tightening punctuation. See byte savings live. - [JavaScript Minifier](https://uttir.com/js-minifier): Quick JS minifier that strips comments and collapses whitespace. Best for trusted, simple code snippets. - [Character Frequency Counter](https://uttir.com/character-frequency): Count how often each character appears in your text. Useful for cryptanalysis, language detection, and stats. - [Reading Time Calculator](https://uttir.com/reading-time): Estimate how long it takes to read or speak a piece of text. Adjustable words-per-minute for fiction, non-fiction, or speech. - [Roman Numeral Converter](https://uttir.com/roman-numeral-converter): Convert integers to Roman numerals (1–3999) and decode Roman numerals back to integers. - [Salary Calculator](https://uttir.com/salary-calculator): Convert between hourly, daily, weekly, biweekly, monthly, and annual salary. Adjust hours/week and weeks/year. - [CSS Gradient Generator](https://uttir.com/css-gradient-generator): Build linear and radial CSS gradients visually. Pick colors, drag stops, copy the CSS. - [Placeholder Image Generator](https://uttir.com/placeholder-image-generator): Generate inline SVG placeholder images at any size with custom text and colors. Pure SVG, no server. - [Countdown Timer](https://uttir.com/countdown-timer): Count down to a specific date and time. Set a target, watch the days/hours/minutes/seconds tick down live. - [User Agent Parser](https://uttir.com/user-agent-parser): Identify the browser, OS, and device type from any user-agent string. Detects bots and crawlers too. - [Temperature Converter](https://uttir.com/temperature-converter) *(new)*: Convert between Celsius, Fahrenheit, and Kelvin. Bidirectional — type in any field, all three update live. - [Cron Expression Generator](https://uttir.com/cron-generator) *(new)*: Build cron expressions from a simple form, or pick a common preset. See plain-English explanations. - [Palindrome Checker](https://uttir.com/palindrome-checker) *(new)*: Check if a word, phrase, or sentence is a palindrome. Also detects anagrams. Case-insensitive, ignores spaces and punctuation. - [Reverse Text](https://uttir.com/reverse-text) *(new)*: Reverse characters, words, or lines in any text. Unicode-safe. Useful for puzzles, mirrored layouts, and word games. - [Sentence & Paragraph Counter](https://uttir.com/sentence-counter) *(new)*: Count sentences, paragraphs, words, characters, and reading time all at once. Find your longest word and average sentence length. - [UUID v7 Generator](https://uttir.com/uuid-v7-generator) *(new)*: Generate RFC 9562 UUID v7 identifiers. Time-sortable, globally unique, generated locally. Batch of 1 to 1000. - [Color Name Finder](https://uttir.com/color-name-finder) *(new)*: Find the closest named color to any hex value. Useful for naming colors, picking palette anchors, and palette inspiration. - [GPA Calculator](https://uttir.com/gpa-calculator) *(new)*: Calculate your weighted GPA from course grades and credits. Supports 4.0, 4.3, 5.0, 10.0, and percentage scales. - [Calorie Calculator (BMR + TDEE)](https://uttir.com/calorie-calculator) *(new)*: Calculate your Basal Metabolic Rate (BMR) and Total Daily Energy Expenditure (TDEE). Includes a goal-adjusted daily calorie target. - [Stopwatch](https://uttir.com/stopwatch) *(new)*: A clean online stopwatch with laps, millisecond precision, and keyboard shortcuts. Runs in your browser. - [Pomodoro Timer](https://uttir.com/pomodoro-timer) *(new)*: A Pomodoro timer with 25/5/15 defaults. Focus, short break, long break, and session counter. Customizable phase lengths. - [Meta Description Length Checker](https://uttir.com/meta-description-checker) *(new)*: Check the length of a meta description against Google’s recommended 70-160 character range. Live verdict and progress bar. - [Page Title Length Checker](https://uttir.com/title-length-checker) *(new)*: Check the length of a page title (or Open Graph title) against Google’s recommended limits. Live character count and verdict. - [Screen Resolution Checker](https://uttir.com/screen-resolution) *(new)*: See your current viewport and screen size, device pixel ratio, color depth, orientation, and more. Useful for responsive design and bug reports. - [Number Base Converter](https://uttir.com/number-base-converter) *(new)*: Convert between binary, octal, decimal, and hexadecimal. Type in any field and the other three update live. - [Date Formatter](https://uttir.com/date-formatter) *(new)*: Format any date in ISO, US, EU, long, short, time, Unix, RFC 2822, and ISO week formats. Also converts Unix timestamps. - [Password Strength Checker](https://uttir.com/password-strength-checker) *(new)*: See how strong a password really is — entropy, time-to-crack, and a list of issues, all computed in your browser. - [My IP Address](https://uttir.com/my-ip) *(new)*: See your public IP, approximate location, ISP, and ASN — useful for VPN checks and remote-access setup. - [Statistics Calculator](https://uttir.com/statistics-calculator) *(new)*: Compute mean, median, mode, range, variance, standard deviation, and quartiles from a list of numbers. - [TOTP Code Generator](https://uttir.com/totp-generator) *(new)*: Generate time-based one-time passwords (2FA codes) from a Base32 secret. Same algorithm as Google Authenticator. - [DNS Lookup](https://uttir.com/dns-lookup) *(new)*: Query DNS records (A, AAAA, MX, TXT, NS, CNAME, SOA, CAA) for any domain using Google DNS-over-HTTPS. - [Permutation & Combination Calculator](https://uttir.com/permutation-combination) *(new)*: Compute nPr and nCr, with optional listing of all arrangements or subsets. Bounded for huge counts. - [Paragraph Counter](https://uttir.com/paragraph-counter) *(new)*: Count paragraphs, words per paragraph, and find the longest/shortest paragraph in your text. Free, runs in your browser. - [Sentence Length Checker](https://uttir.com/sentence-length-checker) *(new)*: Check the length of every sentence in your text. Find sentences that are too long and see the average, median, and length distribution. - [IP Geolocation Lookup](https://uttir.com/ip-geolocation-lookup) *(new)*: Look up geolocation info for any IPv4 or IPv6 address — country, city, ISP, ASN, timezone. Free, runs in your browser. - [CIDR Subnet Calculator](https://uttir.com/cidr-subnet-calculator) *(new)*: Calculate network, broadcast, mask, wildcard, and host range for any IPv4 or IPv6 CIDR block. Pure math, runs in your browser. - [WHOIS / RDAP Lookup](https://uttir.com/whois-lookup) *(new)*: Look up domain or IP registration info via RDAP. Registrar, status, dates, nameservers, contacts. Free, runs in your browser. - [Color Picker from Image](https://uttir.com/image-color-picker) *(new)*: Upload an image and click any pixel to get its HEX, RGB, and HSL color. Works entirely in your browser — your image never leaves your device. - [CSS Flexbox Playground](https://uttir.com/css-flexbox-playground) *(new)*: Visual playground for CSS Flexbox. Adjust container and item properties with sliders, see the live layout update, and copy the generated CSS. - [CSS Grid Playground](https://uttir.com/css-grid-playground) *(new)*: Visual playground for CSS Grid. Define rows, columns, and gaps, place items by area or line number, and copy the generated CSS. - [EXIF / Image Metadata Viewer](https://uttir.com/exif-metadata-viewer) *(new)*: Read EXIF, GPS, IPTC, and other metadata from any image. See camera, lens, location, and timestamp. Your image never leaves your device. - [Currency Converter](https://uttir.com/currency-converter) *(new)*: Convert between 30+ world currencies using static daily-refreshed rates. Fast, private, no API key, no tracking, works offline. - [Emoji Picker](https://uttir.com/emoji-picker) *(new)*: Search and copy emoji by name or category — smileys, hands, animals, food, travel, symbols, and more. Click to copy, paste anywhere. - [HTML to PDF](https://uttir.com/html-to-pdf): Convert HTML to a PDF in your browser. Write or paste HTML, see a live preview, and download a print-ready PDF. No upload, no tracking, no server. - [Barcode Generator](https://uttir.com/barcode-generator): Generate barcodes in 8 formats (EAN, UPC, Code 128, Code 39, ITF, MSI, Codabar, Pharmacode). Download as PNG or SVG. Runs in your browser, no upload. - [CSS Box Shadow Generator](https://uttir.com/css-box-shadow-generator): Visually design CSS box-shadows. Adjust offset, blur, spread, color, and inset. Stack multiple shadows for layered effects. Get the generated CSS instantly. - [CSS Border Radius Generator](https://uttir.com/css-border-radius-generator): Visually design CSS border-radius values. Independent corner control, preset shapes, live preview, and copyable CSS. Includes the "organic" 8-value syntax. - [Random Picker / Wheel of Names](https://uttir.com/random-picker): Pick a random item from a list with a spinning wheel. Great for giveaways, classroom activities, and team decisions. Runs in your browser, no upload. - [Invoice Generator](https://uttir.com/invoice-generator): Create a professional PDF invoice with line items, tax, and totals. No signup, no email gate, no data leaves your browser. - [Image Compressor to Size](https://uttir.com/image-compressor-to-size): Compress a JPG, PNG, or WebP image to an exact target file size in KB. Iteratively re-encodes until the result fits. - [Meme Generator](https://uttir.com/meme-generator): Add classic top-and-bottom text to any image, then download the meme as a PNG. Pick a template or upload your own image. - [JSON Tree Viewer](https://uttir.com/json-tree-viewer): Paste any JSON and explore it as a collapsible tree. Click any value to copy it, or copy the whole path. Free, runs in your browser, no upload. - [Meta Tag Preview](https://uttir.com/meta-tag-preview): See how your page will look in Google search results, Twitter, Facebook, and LinkedIn — before you publish. Type a title and description, upload an image, and the preview updates live. - [Markdown Editor](https://uttir.com/markdown-editor): Write Markdown on the left, see the rendered HTML on the right. Live preview, character / word / line counts, copy HTML or Markdown, drag-drop a file to open it. - [File Compressor (Zip / Unzip)](https://uttir.com/file-compressor): Create a zip archive from any files, or extract one — entirely in your browser. No upload, no signup, no file-size limits beyond what your browser can hold. - [API Tester (HTTP Requests)](https://uttir.com/api-tester): Make HTTP requests from your browser: GET, POST, PUT, DELETE, with custom headers and body. Import a cURL command, see the full response (status, headers, body) with timing. Free, in browser, no signup. - [Image to Text (OCR)](https://uttir.com/ocr): Extract text from any image — screenshots, scanned documents, photos of signs. Choose a language, see the recognized text with confidence, and copy or download it. Free, in browser, no signup. - [PDF OCR — Extract Text from Scanned PDFs](https://uttir.com/pdf-ocr): Pull text out of a scanned PDF in your browser. Each page is rendered at high resolution and recognized locally, with per-page text and a combined export. No upload, no signup. - [Reading Level Calculator](https://uttir.com/reading-level): Check how hard your text is to read. Six readability formulas (Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, Automated Readability Index) in one tool, all in your browser, no upload. - [AES Encrypt / Decrypt](https://uttir.com/aes-encrypt): Encrypt or decrypt text with a password using AES-256-GCM. The encryption runs entirely in your browser, the password never leaves the page, and the result is a portable text envelope you can paste into an email, a chat, or a file. - [Subtitle Converter (SRT, VTT, SUB)](https://uttir.com/subtitle-converter): Convert subtitles between SRT, WebVTT, and MicroDVD SUB. Paste or drop a file, pick the source and target format, and copy the converted text. Includes a timing-shift and a time-scale tool. Free, in your browser, no upload. - [QR Code Decoder](https://uttir.com/qr-decoder): Read the text or URL hidden in any QR code image. Drop in a screenshot, a photo, or a saved QR, and get the decoded payload. Detects URLs, emails, Wi-Fi credentials, and vCards. Free, in your browser, no upload. - [Text to Speech](https://uttir.com/text-to-speech): Read any text aloud using your browser's built-in voice. Pick from the voices your operating system provides, set the speed and pitch, and click play. Free, in your browser, no upload, no signup. - [Headline Analyzer](https://uttir.com/headline-analyzer): Score any headline on word count, character count, power words, sentiment, and clarity. Get a letter grade and a per-dimension tip. Free, in your browser, no upload. - [Co-founder Equity Calculator](https://uttir.com/cofounder-equity): Split startup equity between co-founders, see the 4-year vesting schedule with 1-year cliff, and simulate dilution from a future funding round. Free, in your browser, no upload. - [Writing Style Analyzer](https://uttir.com/writing-style): Highlight adverbs, passive voice, complex words, and hard sentences in your text. Paste any draft and see the issues in real time. Free, in your browser, no upload. - [Business Name Generator](https://uttir.com/business-name): Generate brand-name ideas for your startup, product, or project. Pick a style (modern, classic, playful, technical) and get a batch of names with the .com domain suggestion. Free, in your browser, no upload. - [Random Name Generator](https://uttir.com/random-name): Generate random first and last names for mockups, test data, or placeholder content. Filter by gender (any, male, female, neutral) and region (English, Spanish, French, German, Japanese, Chinese, Arabic). Free, in your browser, no upload. - [Signature Maker](https://uttir.com/signature): Draw a handwritten signature in your browser with mouse, trackpad, or touch. Pick a pen color, set the stroke width, and download the result as a transparent PNG. Free, no upload. - [Typing Test](https://uttir.com/typing-test) *(new)*: Test your typing speed with famous book passages. Live WPM and accuracy as you type. Cryptographically fair timer. - [Coin Flip](https://uttir.com/coin-flip) *(new)*: Flip a virtual coin or roll dice. Cryptographically fair randomness, runs in your browser, history tracked per session. ## Categories - [Developer Tools](https://uttir.com/developer-tools) (58 tools): Format, validate, decode, and generate the things developers deal with every day. - [Text Tools](https://uttir.com/text-tools) (34 tools): Count, convert, compare, and clean up text instantly. - [Calculators](https://uttir.com/calculators) (25 tools): Quick, accurate calculators for percentages, dates, ages, and finance. - [Color Tools](https://uttir.com/color-tools) (10 tools): Pick colors, convert formats, and check accessibility. - [Image Tools](https://uttir.com/image-tools) (21 tools): Convert, compress, and resize images without uploading them. - [PDF Tools](https://uttir.com/pdf-tools) (8 tools): Merge, split, and convert PDFs locally in your browser. - [Converters](https://uttir.com/converters) (19 tools): Convert between formats, units, and standards. - [SEO Tools](https://uttir.com/seo-tools) (11 tools): Generate meta tags, sitemaps, robots.txt, and UTM links. - [File Tools](https://uttir.com/file-tools) (3 tools): Work with files directly in your browser. - [Generators](https://uttir.com/generators) (23 tools): Generate passwords, IDs, dummy data, and more. - [Date & Time Tools](https://uttir.com/date-time-tools) (8 tools): Work with dates, times, durations, and time zones. - [Encoding Tools](https://uttir.com/encoding-tools) (9 tools): Encode and decode Base64, URLs, HTML entities, and more. - [Data Tools](https://uttir.com/data-tools) (10 tools): Transform CSV, JSON, XML, and YAML. - [Web Tools](https://uttir.com/web-tools) (18 tools): Utilities for building and testing websites. - [Media Tools](https://uttir.com/media-tools) (2 tools): Work with audio and video in your browser. - [Security Tools](https://uttir.com/security-tools) (7 tools): Check, generate, and decode security primitives in your browser. - [Network Tools](https://uttir.com/network-tools) (6 tools): Look up IP, DNS, WHOIS, and HTTP headers from your browser. - [Math Tools](https://uttir.com/math-tools) (14 tools): Statistics, equations, sequences, and number theory. ## Blog Long-form guides, tutorials, and roundups. Updated as new posts are published. - [All posts](https://uttir.com/blog) - [RSS feed](https://uttir.com/blog/feed.xml) - [The 12 Best Free Developer Tools in 2026 (No Signup, No Upload)](https://uttir.com/blog/best-free-developer-tools-in-2026-no-signup): A curated list of the best free developer tools that run in your browser. Format, validate, generate, convert, debug — all without an account, all without sending your code to a server. - [The 8 Best Free Image Compression Tools in 2026 (No Upload)](https://uttir.com/blog/best-free-image-compression-tools-in-2026-no-upload): A roundup of the best free image compression tools for JPG, PNG, and WebP. All of them run in your browser, so your photos never leave your device. Some let you target a specific file size in KB. - [The 9 Best Free PDF Tools in 2026 That Don’t Upload Your Files](https://uttir.com/blog/best-free-pdf-tools-in-2026-that-dont-upload-your-files): A roundup of the best free PDF tools for merge, split, compress, convert, OCR, sign, and more — all of which run in your browser and never send your documents to a server. - [The Anatomy of a Perfect Stack Trace](https://uttir.com/blog/the-anatomy-of-a-perfect-stack-trace): A stack trace is a map of where your code was when it crashed. Most people read it backwards. The actual bug is almost never where you think it is. Here is how to read a stack trace top-to-bottom, the four lines that matter, the seven lines that lie, and how to find the real bug in 30 seconds. - [How to Extract Text From a PDF Without Paying for Adobe](https://uttir.com/blog/how-to-extract-text-from-a-pdf-without-paying-for-adobe): PDFs are the universal document format for sharing, but the universal pain for editing. You can extract the text for free, in your browser, without uploading the file to a server. Here is the workflow for native-text PDFs (most modern ones) and scanned PDFs (older or image-only ones), with no Adobe subscription required. - [The 9 Best Free Image Tools for Bloggers in 2026 (No Upload, No Watermark)](https://uttir.com/blog/best-free-image-tools-for-bloggers-in-2026): Blog images need to be the right size, the right format, and the right quality — usually under 200 KB so the page loads fast. Here are nine browser-based tools that handle every step of a blog image workflow: resizing, compressing, converting, cropping, adding alt text, and generating favicons. All free, all without uploading your images. - [The 7 Most Common Password Mistakes (And Why They Still Matter in 2026)](https://uttir.com/blog/the-7-most-common-password-mistakes-and-why-they-still-matter): Passwords have been around for 60 years. The mistakes people make with them have been around almost as long. Here are the seven most common, why each one is still a problem, and the five-minute fix that closes most of them — including the one nobody talks about (your password manager's master password). - [How to Build a Pomodoro Schedule That Actually Works](https://uttir.com/blog/how-to-build-a-pomodoro-schedule-that-actually-works): The 25-minute pomodoro is a starting point, not a rule. Some people focus better in 50-minute blocks, some in 90. Some need 5-minute breaks, some need 15. Here is how to build a pomodoro schedule that fits your work, your energy, and your task type, and how to track what is working. - [What Is Regex, and When Should You Actually Use It?](https://uttir.com/blog/what-is-regex-and-when-you-should-actually-use-it): A regular expression is a tiny language for matching patterns in text. It is one of the most useful tools in programming — and one of the most overused. Here is what regex is, the four operators that cover 90% of real-world use, the four signs you should not use regex, and how to test one in your browser before you commit it to production. - [How to Write a README That Actually Gets Read](https://uttir.com/blog/how-to-write-a-readme-that-actually-gets-read): A README is the first thing a visitor sees. Most READMEs are walls of text that nobody reads. The good ones are short, scannable, and answer the four questions every visitor has: what is this, why should I care, how do I use it, and how do I install it. Here is the structure, with examples. - [What Is a Unix Timestamp? (And Where You'll See One)](https://uttir.com/blog/what-is-a-unix-timestamp-and-where-youll-see-one): A Unix timestamp is the number of seconds since January 1, 1970, UTC. It is the universal time format for computers: small, sortable, timezone-independent, and trivially comparable. Here is what it is, where you will see one, the Year 2038 problem, and how to convert to and from a human-readable date in your browser. - [What Is a Sitemap (And Why Every Website Needs One)?](https://uttir.com/blog/what-is-a-sitemap-and-why-every-website-needs-one): A sitemap is a file that lists every page on your website in a format search engines can read. It is the most basic SEO tool, and most websites either do not have one or have one with errors. Here is what a sitemap does, the format, how to generate one without uploading your site to a server, and the seven things that go wrong. - [How to Convert a CSV to a JSON Database (In Your Browser, No Upload)](https://uttir.com/blog/how-to-convert-a-csv-to-a-json-database): A CSV is a flat table. JSON is a tree. Converting between them is one of the most common tasks in modern data work, and a good converter handles quoting, escapes, type inference, and the dozen edge cases that bite you in production. Here is what a converter does, and how to convert without uploading your data. - [The Hidden Cost of Free Online Tools (And Why We Don't Sell Your Data)](https://uttir.com/blog/the-hidden-cost-of-free-tools): If a tool is free and you are not the customer, you are the product. That is the standard line. It is true for most free online tools. Here is what it actually costs, what we do instead to keep this site free, and the four things you can check in 30 seconds to know if a free tool is selling you. - [7 Signs You're Looking at a Bot (And How to Check in 10 Seconds)](https://uttir.com/blog/7-signs-youre-looking-at-a-bot): Most bots announce themselves in the User-Agent string. A few pretend to be real browsers. Here are the seven reliable signals, the order to check them, and how to look up any user agent in a browser-based parser to see exactly what kind of client is hitting your site. - [The Anatomy of a Perfect API Request](https://uttir.com/blog/the-anatomy-of-a-perfect-api-request): A good API request has six parts: method, URL, headers, body, authentication, and a way to handle the response. Most failed requests fail because one of those parts is wrong. Here is a tour of what each part does, the common mistakes, and the order in which to debug a failing request. - [How to Make a Great Invoice in 5 Minutes (Free, No Signup, No Upload)](https://uttir.com/blog/how-to-make-a-great-invoice-in-5-minutes): A good invoice has six required fields and one optional one. Most invoice generators bury those fields behind an account wall. Here is what goes in each field, the seven mistakes that make invoices hard to pay, and how to generate one in your browser without uploading your financial data anywhere. - [How to Compress a Photo to Under 100 KB (Without Making It Look Bad)](https://uttir.com/blog/how-to-compress-a-photo-to-under-100-kb): Government forms, job applications, and visa portals all want photos under 100 KB or 200 KB. Here is how to hit those targets without uploading your photo to a server, without losing sharpness, and without paying for Photoshop. A good compressor lets you pick a target size, not a quality slider. - [What Is an SRT File? (And How Do You Read a Subtitle File)](https://uttir.com/blog/what-is-srt-and-how-do-you-read-a-subtitle-file): SRT is the most common subtitle format: numbered cues with start and end timestamps and the text to display. Learn the structure, why it has weird line breaks, how to convert SRT to VTT or SUB, and how to fix the three most common mistakes (off-by-one timing, encoding, and Windows line endings). - [How to Navigate a Huge JSON File (Without Losing Your Mind)](https://uttir.com/blog/how-to-navigate-a-huge-json-file): A 5MB JSON blob with thousands of nested keys is not a file, it is a maze. A tree view lets you collapse what you do not need, search across the whole document, copy a single value, and find the path to a field in seconds. Here is how to use one, and how to keep your document on your device. - [How to Test an API Without Postman (or Insomnia, or Hoppscotch)](https://uttir.com/blog/how-to-test-an-api-without-postman): You can make HTTP requests, inspect headers, send JSON bodies, and check response status without installing a desktop client. The browser is enough. Here is a practical workflow using only a free, browser-based tool that keeps your requests on your device. - [What Is a Cron Expression? A Beginner's Guide With Examples](https://uttir.com/blog/what-is-a-cron-expression-a-beginners-guide): A cron expression is a 5-field syntax for scheduling recurring tasks. Learn what each field means, the special characters (*, /, -, ,), common patterns (every minute, every hour, weekdays at 9am), and how to build one without memorising the syntax. - [How to Generate a Cryptographically Secure Random Number in Your Browser](https://uttir.com/blog/how-to-generate-a-cryptographically-secure-random-number): Math.random() is not secure. Learn why, what "secure" means for random number generation, the right browser API to use (crypto.getRandomValues), and how to generate a random number in a range without bias. - [The Hidden Cost of Pretty URLs (and What Actually Makes a Good Slug)](https://uttir.com/blog/the-hidden-cost-of-pretty-urls-and-what-makes-a-good-slug): A URL slug is the human-readable part of a URL after the domain. Good slugs are short, descriptive, stable, and lowercase. Learn the rules, the tradeoffs, why "auto-generated IDs" are usually better than pretty slugs, and how to generate one that will not bite you in six months. - [How to Validate an Email Address Without Sending a Test Email](https://uttir.com/blog/how-to-validate-an-email-address-without-sending-a-test-email): A syntactically valid email address is not the same as a deliverable one. Learn the three layers of email validation (syntax, domain, mailbox), what each catches, what each misses, and the right tool for each — without sending a single test message. - [How to Convert Markdown to HTML Without Writing a Single Line of Code](https://uttir.com/blog/how-to-convert-markdown-to-html-in-your-browser): Markdown is the universal plain-text format; HTML is the universal markup language. Learn the difference, when you need to convert between them, and how to do it in your browser with no upload, no library, and no build step. - [The 7 Best Free SEO Tools That Aren’t Called Ahrefs](https://uttir.com/blog/best-free-seo-tools-that-arent-called-ahrefs): Meta tag generators, SERP previewers, keyword density checkers, JSON-LD generators, sitemap builders, and robots.txt writers — seven free SEO tools that cover the on-page work Ahrefs and SEMrush charge $99/month for. No signup, no upload, no account. - [How to Build a Perfect CSS Box Shadow in 5 Minutes](https://uttir.com/blog/how-to-build-a-perfect-css-box-shadow-in-5-minutes): A good CSS box shadow is subtle, layered, and matches the lighting of the rest of the design. Learn the four-part anatomy of a real shadow (offset, blur, spread, color), the trick of stacking two shadows for depth, and the values that work in production. - [What Is Aspect Ratio (and Why Photographers Care About It)](https://uttir.com/blog/what-is-aspect-ratio-and-why-photographers-care-about-it): Aspect ratio is the proportional relationship between an image's width and height. Learn the standard ratios (4:3, 3:2, 16:9, 1:1), why photographers obsess over them, how to calculate the right crop for a target ratio, and the difference between aspect ratio and resolution. - [How to Minify HTML, CSS, and JavaScript Without Breaking Your Site](https://uttir.com/blog/how-to-minify-html-css-and-javascript-without-breaking-your-site): Minification shrinks your HTML, CSS, and JavaScript files by removing whitespace, comments, and dead code. Learn what it does, what it does not do, when to use it, and how to safely minify a file in your browser without uploading the source. - [The 8 Best Free Color Tools for Designers in 2026 (No Upload)](https://uttir.com/blog/best-free-color-tools-for-designers-in-2026): Color pickers, palette generators, contrast checkers, color name finders, and converters — eight free color tools that run in your browser, do not upload your images or palettes, and cover every color task a designer actually has. - [What Is a Pomodoro Timer (and Why It Actually Works)](https://uttir.com/blog/what-is-a-pomodoro-timer-and-why-it-actually-works): The Pomodoro Technique is a 25-minute focus timer with 5-minute breaks, invented in the late 1980s. It works because of how attention and fatigue actually behave, not because of the timer. Learn the original rules, the science, the variations, and how to run a Pomodoro session in your browser. - [The 5 Most Common JSON Mistakes (and How to Catch Them Before Production)](https://uttir.com/blog/the-5-most-common-json-mistakes-and-how-to-catch-them): Trailing commas, unquoted keys, single quotes instead of double, comments in JSON, and NaN as a value — the five mistakes that show up in every JSON file that breaks in production. Learn what they are, why parsers reject them, and how to catch them before they ship. - [How to Format SQL Like a Senior Engineer](https://uttir.com/blog/how-to-format-sql-like-a-senior-engineer): Pretty SQL is readable SQL. Learn the formatting rules senior engineers use (uppercase keywords, aligned columns, consistent indentation, no SELECT *), why they matter, and how to format any query automatically in your browser. - [What Is Lorem Ipsum (and When You Actually Need It)](https://uttir.com/blog/what-is-lorem-ipsum-and-when-you-actually-need-it): Lorem ipsum is placeholder text designers and developers use to fill a layout before the real copy exists. Learn where it came from, when to use it, when not to, and how to generate the right amount of it for your project. - [How to Remove EXIF Metadata from Photos Before Sharing Online](https://uttir.com/blog/how-to-remove-exif-metadata-from-photos-before-sharing): Every photo you take with a smartphone contains EXIF metadata: the camera make and model, the date and time, and — if you have location services on — the GPS coordinates of where you took it. Before sharing a photo publicly, strip the EXIF. Here is the 3-step workflow: check the metadata, remove it, verify the result. The whole thing takes 2 minutes per photo. - [The 12 Best Free Online Tools You Haven’t Heard of in 2026](https://uttir.com/blog/best-free-online-tools-you-havent-heard-of-in-2026): Twelve free online tools that are genuinely useful and not on the front page of every "best of" list: a CSS box-shadow generator, a JWT decoder, a binary-to-hex converter, a regex tester with explanations, a Cron expression generator, an EXIF metadata viewer, a CSS gradient maker, a base32 encoder, an HTTP status code reference, a JSON tree viewer, a UUID generator with history, and a CSS clip-path playground. All run in your browser, no signup, no upload. - [How to Convert a CSV to JSON in Your Browser (No Upload)](https://uttir.com/blog/how-to-convert-a-csv-to-json-in-your-browser): A 4-step workflow to convert a CSV file to JSON in your browser: paste the CSV, pick the delimiter, pick the conversion mode (array of objects, array of arrays, or keyed object), copy the JSON. The whole thing takes 30 seconds, runs entirely in the browser, and never sends your data to a server. Works for any CSV up to a few MB. - [What Is a CSV File (and Why Every Tool Imports and Exports One)](https://uttir.com/blog/what-is-a-csv-file-and-why-every-tool-uses-it): A CSV is a plain text file where each row is a line and each column is separated by a comma. That is the whole spec. Despite being that simple, CSV is the universal interchange format for tabular data: every spreadsheet, database, CRM, analytics tool, and accounting app can import and export it. Here is why it has lasted 50 years and what to watch for. - [In Defense of Plain Text (and Why It Beats Every Note-Taking App)](https://uttir.com/blog/in-defense-of-plain-text): Plain text is 60 years old and still the most durable, portable, searchable, scriptable, and future-proof format for human-written information. Every note-taking app eventually becomes a plain-text export or a dead format. Plain text files in a folder, indexed by grep, are a tool that will outlive every app you use today. Here is the case. - [The 7 Free Calculators That Replace a Spreadsheet (and Are Faster)](https://uttir.com/blog/7-free-calculators-that-replace-a-spreadsheet): A spreadsheet is overkill for one-off calculations: a tip, a BMI, a percentage change, a loan payment, a tip split, an age, and a unit conversion. The free calculator tools on this site do each of these in 5 seconds, run in your browser, and never ask you to log in or upload anything. Here is when to use which. - [How to Build a Color Palette From a Logo (5 Minutes)](https://uttir.com/blog/how-to-build-a-color-palette-from-a-logo-in-5-minutes): A 5-step workflow to extract a working color palette from any logo image: pick the dominant color, generate 4 supporting colors using a 60-30-10 rule, check contrast for accessibility, test the palette in dark mode, and export the hex codes. Takes 5 minutes once you have done it twice. - [How to Read a JWT Token (Without Trusting the Sender)](https://uttir.com/blog/how-to-read-a-jwt-token-without-trusting-the-website): A JWT is three base64 strings joined by dots. The middle one is the payload, and it is usually readable without any verification. The header tells you the algorithm. The signature is what you would verify to trust the contents. Here is how to read each part, with worked examples. - [How to Spot a Phishing URL Before You Click (in 10 Seconds)](https://uttir.com/blog/how-to-spot-a-phishing-url-before-you-click): Phishing URLs are designed to look real at a glance. The 6 things to look for in the domain (lookalike characters, extra subdomains, wrong TLD, mismatched display vs. actual URL, suspicious path, and URL-encoded junk) take 10 seconds to scan. Here is the checklist, with worked examples. - [The Meta Tags Cheat Sheet: 13 Tags and Which Ones Actually Matter](https://uttir.com/blog/the-meta-tags-cheat-sheet): There are 13 meta tags that affect how your page looks in search results, in social shares, and on mobile. Three of them matter for SEO. Five matter for social sharing. The other five are either obsolete or nice-to-have. Here is the cheat sheet, with what each one does and when to skip it. - [Cron Expressions for People Who Hate Cron Expressions](https://uttir.com/blog/cron-expressions-for-people-who-hate-cron-expressions): A cron expression is 5 fields, each a number, a wildcard, or a step. Once you know what each field means and how the steps work, the expressions stop looking like a typo and start looking like a tiny schedule. Here is the cheat sheet, in plain language. - [A Short History of the Favicon (from One 16×16 Icon to 8 Files)](https://uttir.com/blog/a-short-history-of-the-favicon): The favicon started as a single 16×16 ICO file in 1999. In 2026, a complete favicon setup is 8 files: a 16×16, 32×32, 180×180 (Apple), 192×192, 512×512 (PWA), a manifest.json, and a site.webmanifest. Here is the 27-year history and what you actually need today. - [The Hidden Cost of Free Tier SaaS](https://uttir.com/blog/the-hidden-cost-of-free-tier-saas): A free tier is a marketing budget, not a price. The vendor is paying for your signup, your usage, and your data, expecting a conversion later. The conversion usually comes at the moment when switching is hardest. Here are 6 cases where the paid tier is the cheaper choice. - [Why Temperature Converter APIs Are Wrong 90% of the Time (and How to Spot It)](https://uttir.com/blog/why-temparature-converter-apis-are-wrong-90-percent-of-the-time): Most temperature converter APIs use a single formula: T(F) = T(C) × 9/5 + 32. The formula is correct. The implementation is usually wrong. Here is why, when it matters, and how to verify. - [What Nobody Tells You About UUIDs as Database Primary Keys](https://uttir.com/blog/what-nobody-tells-you-about-uuids-as-database-primary-keys): UUIDs look like a free win for primary keys: globally unique, no coordination, no information leak. The reality is more nuanced. They are 2x larger, 2-5x slower to index, and split awkwardly in B-tree indexes. Here is the honest tradeoff. - [When the Best Developer Tool Is No Tool (and When It Is)](https://uttir.com/blog/when-the-best-developer-tool-is-no-tool): There is a point in every debugging session, every refactor, every "let me just check this real quick" where the right tool is no tool. The mouse goes down. The terminal closes. The thinking begins. Here is when to step away from the tool, when not to, and the cost of getting it wrong. - [The Anatomy of a Great Email Signature (with 7 Examples You Can Copy)](https://uttir.com/blog/the-anatomy-of-a-great-email-signature): A good email signature has 4-6 lines: name, role, company, contact, and a single link. A bad one has a logo, a quote, three social icons, a disclaimer, and a phone number in tiny gray text. Here is what to include, what to cut, and seven examples. - [The Surprising Physics of a Stopwatch vs a Countdown Timer](https://uttir.com/blog/the-surprising-physics-of-a-stopwatch-vs-a-countdown-timer): A stopwatch counts up. A countdown counts down. They look like the same tool with the direction flipped. They are not. The physics of measuring time, the cognitive load of waiting, and the use cases are different. Here is why. - [A Field Guide to Image Formats in 2026 (PNG, JPG, WebP, AVIF, HEIC)](https://uttir.com/blog/a-field-guide-to-image-formats-in-2026): There are six image formats that matter in 2026: PNG, JPG, WebP, AVIF, HEIC, and SVG. Each has a specific use case. Using the wrong one costs you 3-10x in file size, in quality, or in compatibility. Here is the honest field guide. - [The Myth of the Secure Password in 2026 (and What Actually Matters)](https://uttir.com/blog/the-myth-of-the-secure-password-in-2026): A "secure" password is no longer the bottleneck. The bottleneck is everything around the password. Here is what the threat model actually looks like in 2026, why a 16-character random password is not enough on its own, and the four things that actually keep you safe. - [In Defense of the QR Code in 2026](https://uttir.com/blog/in-defense-of-the-qr-code-in-2026): QR codes get mocked as a 2010s relic, but in 2026 they are still the cheapest, fastest, and most universal way to move a phone from a screen to an action. Here is why the alternatives all have a specific failure mode the QR code does not. - [5 Signs Your Color Palette Is Pretentious (and How to Fix It)](https://uttir.com/blog/5-signs-your-color-palette-is-pretentious): A pretentious color palette is one that tries too hard. It uses 12 colors when 4 would do, picks unique hues for every button, or insists on "sophisticated" muted tones that look the same on screen. Here are the five signs, why each one is a problem, and what to do instead. - [A Defense of the Roman Numeral in Modern Software (Yes, Really)](https://uttir.com/blog/a-defense-of-the-roman-numeral-in-modern-software): Roman numerals look like a relic. They are hard to read, hard to write, and there is no reason to use them in software. Except when there is. Here is the case for keeping them, the cases where they actually help, and the surprising places they still show up. - [Why Most Color Pickers Are Wrong About 1 Pixel (and Why It Matters)](https://uttir.com/blog/why-most-color-pickers-are-wrong-about-1-pixel): A color picker tells you the color of a single pixel. But a pixel is not a color — it is a sample of a continuous function, and the sample is usually wrong. Here is why, when it matters, and what to do about it. - [What Typing Speed Actually Measures (and What It Does Not)](https://uttir.com/blog/what-typing-speed-actually-measures): Words per minute is the most common typing speed metric, but it is not what you think. Here is what WPM actually counts, why 5-characters-per-word is the convention, what "net WPM" vs "gross WPM" means, why your accuracy matters more than your speed past a certain point, and how to actually get faster. - [The Math Behind a Fair Coin Flip (and Why Your Brain Lies About It)](https://uttir.com/blog/the-math-behind-a-fair-coin-flip): A coin flip is the simplest random experiment. The math is 50/50, the physics is messy, and your brain is the worst part. Here is what "fair" actually means, why a flipped coin is not exactly 50/50, why 100 flips rarely show exactly 50/50, and how to verify a tool is using real randomness. - [When to Use a Decision Maker, and When You Should Trust Yourself](https://uttir.com/blog/when-to-use-a-decision-maker-and-when-not-to): A decision maker is a tiebreaker, not a replacement for judgment. Here is when it actually helps (analysis-paralysis on equal options, breaking a long deadlock, choosing between two equivalent things), and when it makes things worse (when one option is clearly better, when you have not done the analysis, when the decision matters and you need to own it). - [The 9 Best Free Image Tools in 2026 (That Respect Your Privacy)](https://uttir.com/blog/best-free-image-tools-2026-that-respect-your-privacy): Nine free image tools that work in your browser without uploading your photos to a server. Convert, compress, resize, crop, color-pick, and read EXIF in seconds — no account, no upload, no watermark. - [The 8 Best Free PDF Tools in 2026 (That Actually Work in Your Browser)](https://uttir.com/blog/best-free-pdf-tools-2026-that-actually-work): Eight free PDF tools that work in your browser without uploading your files to a server. Merge, split, compress, convert, OCR, sign, and edit PDFs in seconds — no account, no upload, no watermark. - [8 Clever QR Code Uses You Haven’t Tried Yet (and 3 You Should Avoid)](https://uttir.com/blog/8-clever-uses-for-qr-codes-you-havent-tried): A practical guide to QR codes in 2026: the 8 most useful non-obvious uses (Wi-Fi sharing, contact cards, restaurant menus, payment, event tickets, two-factor backup, package tracking, and table-top donation), the 3 cases where QR codes are a bad idea, and how to generate a working code in your browser without uploading anything. - [5 Rules for a Color Palette That Actually Works in 2026](https://uttir.com/blog/5-rules-for-a-color-palette-that-actually-works): A practical guide to choosing a color palette: the 5 rules that separate a working palette from a decorative one (60-30-10 distribution, start with one color, neutrals are colors, contrast beats hue, test in context), common mistakes, and how to use a browser-based palette generator without uploading anything. - [Best Free JSON Viewers and Formatters That Respect Your Privacy](https://uttir.com/blog/best-free-json-viewers-that-respect-your-privacy): A practical guide to JSON viewers and formatters: the 8 best browser-based tools in 2026, what makes each one different, the privacy question (most popular JSON viewers upload your data), and how to format, validate, and explore JSON without sending it to a remote server. - [JSON Schema Explained: What It Is, Why You Need It, and How to Start](https://uttir.com/blog/json-schema-explained-what-it-is-and-when-you-need-it): A practical guide to JSON Schema: what it is (a way to describe the shape of valid JSON), why it matters (catches bugs at the API boundary, generates docs, powers form libraries), the basic syntax, and how to start using it in your own projects. - [Markdown vs HTML vs Rich Text: Which Format Wins for Content Creation?](https://uttir.com/blog/markdown-vs-html-vs-rich-text-which-format-wins): A practical guide to content formats: the three choices (Markdown, HTML, rich text), the trade-offs (readability, control, portability), the right format for each use case (blog, documentation, email, code, books), and the conversion workflow that keeps everything in sync. - [What Is the Name of That Color? A Field Guide to CSS Color Naming](https://uttir.com/blog/what-is-the-name-of-that-color-a-field-guide): A practical guide to CSS color naming: the difference between HEX, RGB, HSL, and named colors; why "tomato" looks the way it does; how to find the right name for a color you can see; the most useful CSS named colors by category; and how to find them in your browser without uploading anything. - [MD5 vs SHA-1 vs SHA-256 vs SHA-3: When to Use Each Hash Function](https://uttir.com/blog/md5-vs-sha-1-vs-sha-256-vs-sha-3): A practical guide to cryptographic hash functions: what a hash is for, the four real-world choices (MD5, SHA-1, SHA-256, SHA-3), the speed vs. security trade-offs, the deprecation timeline, and which one to use for each common use case. - [The 6 Password Mistakes That Cost You in 2026 (and How to Avoid Them)](https://uttir.com/blog/6-password-mistakes-that-cost-you): The six password mistakes almost everyone makes in 2026: weak passwords, password reuse, no 2FA, storing in browsers, sharing via text, and ignoring breach notifications. What actually goes wrong, the realistic cost of each, and the five-minute fix for each one. - [How to Measure the Reading Level of Your Writing (and What the Scores Mean)](https://uttir.com/blog/how-to-measure-the-reading-level-of-your-writing): A practical guide to the six most common readability formulas: Flesch Reading Ease, Flesch-Kincaid Grade, Gunning Fog, SMOG, Coleman-Liau, and ARI. The differences, the math, the right one for the right audience, and how to run all six in your browser without uploading your draft anywhere. - [How to Encrypt a Message with a Password (in Your Browser)](https://uttir.com/blog/how-to-encrypt-a-message-with-a-password): A practical guide to password-based encryption: how AES-GCM with PBKDF2 actually works, why the wire format matters for future compatibility, the common foot-guns (weak passwords, no integrity check, ECB mode), and how to encrypt a message in your browser without trusting a remote service with the plaintext. - [How to Convert SRT to VTT or SUB (and Why You Might Need To)](https://uttir.com/blog/how-to-convert-srt-to-vtt-or-sub): A practical guide to subtitle formats: the differences between SRT, WebVTT, and MicroDVD SUB, the format compatibility matrix for common players, the timing-shift and FPS-scaling cases that come up when subtitles drift, and how to convert everything in your browser without uploading your file anywhere. - [How to Build a CSS Grid Layout (with Real Examples)](https://uttir.com/blog/how-to-build-a-css-grid-layout): A practical guide to CSS Grid: when to use it (and when flexbox is the better choice), the six properties that matter, how named lines and areas work, and how to experiment with a live layout in your browser before committing it to a stylesheet. - [How to Build a CSS Flexbox Layout (with Real Examples)](https://uttir.com/blog/how-to-build-a-css-flexbox-layout): A practical guide to flexbox: when to use it (and when not to), the six properties that matter, the common gotchas with align-items and flex-basis, and how to experiment with a live layout in your browser before committing it to a stylesheet. - [How to Pick a Random Number Fairly (and Why Math.random Is Wrong)](https://uttir.com/blog/how-to-pick-a-random-number-fairly): A practical guide to random numbers: the difference between Math.random and crypto.getRandomValues, why fairness matters for giveaways and raffles, how to roll dice and shuffle a list in your browser, and the one case where randomness is genuinely hard. - [How to Calculate Permutations and Combinations (with Worked Examples)](https://uttir.com/blog/how-to-calculate-permutations-and-combinations): A practical guide to counting: the difference between permutations (order matters) and combinations (order does not), the formula for each, the common real-world cases, and how to run the calculation in your browser without pulling out a calculator or a textbook. - [How to Calculate Age Exactly (in Years, Months, and Days)](https://uttir.com/blog/how-to-calculate-age-exactly): A practical guide to age math: the difference between calendar years and elapsed time, why "years old" is fuzzier than you think, how to handle leap years and time zones, and how to get an exact result in your browser without uploading your birth date to anyone. - [How to Read EXIF Data from a Photo (and Why It Matters)](https://uttir.com/blog/how-to-read-exif-data-from-a-photo): A practical guide to EXIF metadata: what is in it, what it reveals about you, the difference between EXIF and IPTC and XMP, the common cases where you want to strip it, and how to read it in your browser without uploading the photo anywhere. - [How to Make a Barcode for Your Product (the Right Way)](https://uttir.com/blog/how-to-make-a-barcode-for-your-product): A practical guide to barcodes for small business and product teams: the differences between UPC, EAN, Code 128, and QR, when you need a real GS1-issued code, and how to generate a working barcode in your browser in seconds. - [How to Calculate a Tip (and Split the Bill Fairly)](https://uttir.com/blog/how-to-calculate-a-tip-and-split-the-bill): A practical guide to tipping: the standard rates by country, the math for splitting uneven orders, the difference between pre-tax and post-tax tipping, and how to do the whole thing in your browser without a calculator app or a back-of-the-napkin argument. - [How to Calculate Loan Payments and Amortization (the Right Way)](https://uttir.com/blog/how-to-calculate-loan-payments-and-amortization): A practical guide to loan math: the formula, what amortization actually means, the difference between APR and APY, what extra payments really save, and how to get a full amortization schedule in your browser without sending your numbers to a bank. - [How to Convert HTML to PDF in Your Browser (No Upload, No Server)](https://uttir.com/blog/how-to-convert-html-to-pdf-in-your-browser): A practical guide to HTML-to-PDF conversion: when to use it, the difference between the browser print path and a real PDF library, the formatting gotchas that trip people up, and how to get a clean PDF in your browser without sending the source to anyone. - [How to Convert Currency Without Sending Your Data Anywhere](https://uttir.com/blog/how-to-convert-currency-without-sending-data): A practical guide to currency conversion: the data sources, the common pitfalls (bank vs. mid-market rate, fees, daily drift), and how to get a fast, accurate conversion in your browser without uploading your amounts to anyone. - [How to Calculate BMI the Right Way (and What It Actually Means)](https://uttir.com/blog/how-to-calculate-bmi-the-right-way): A practical guide to BMI: the formula, the four standard categories, why the number is rough, what to use alongside it, and how to calculate it in your browser without sending your data anywhere. - [How to Check Keyword Density (and Why It Matters Less Than You Think)](https://uttir.com/blog/how-to-check-keyword-density): A practical guide to keyword density: what it is, what numbers actually matter, the difference between modern keyword analysis and the 2010 stuffing era, and how to run the check in your browser in 10 seconds. - [How to Write Headlines That Get Clicks (and Rank)](https://uttir.com/blog/how-to-write-headlines-that-get-clicks): A practical guide to writing headlines that earn both search rankings and click-throughs. The eight dimensions that actually matter, the mistakes that quietly cost you traffic, and a self-check you can run in your browser before publishing. - [How to Split Startup Equity Fairly (and Why 50/50 Is Usually Wrong)](https://uttir.com/blog/how-to-split-startup-equity-fairly): A practical guide to splitting equity between co-founders: the four factors that actually drive a fair split, the standard 4-year vesting with 1-year cliff, why equal splits are usually wrong, and how to use a simple calculator to test your split before it is too late to change. - [How to Write Clear Prose (the Hemingway Way, Without the Robot Edits)](https://uttir.com/blog/how-to-write-clear-prose-hemingway): A practical guide to writing prose that reads cleanly on the first pass: cut the adverbs, switch to active voice, shorten the long sentences, and know when to ignore every rule. With a self-check you can run in your browser before publishing. - [How to Name Your Business or Startup (Without Regretting It in Year Two)](https://uttir.com/blog/how-to-name-your-business-or-startup): A practical guide to naming a business: what makes a name good in the first place, the test that catches 80% of bad names, how to find an available .com, and the check you should do before you commit. With a free in-browser name generator for brainstorming. - [Best Free UTM Builders That Actually Respect Your Privacy](https://uttir.com/blog/best-free-utm-builders-that-respect-privacy): A practical guide to building UTM campaign links that track accurately in Google Analytics: what the five UTM parameters do, the naming conventions that keep your reports clean, and the privacy-first alternatives to the popular SaaS UTM builders that log your campaigns. - [How to Make a Handwritten Signature Online (and Why It Is Almost Always Wrong)](https://uttir.com/blog/how-to-make-a-handwritten-signature-online): A practical guide to creating a digital signature: when a real drawn signature is the right pick, when a typed name is fine, and the 60-second test that tells you which you need. With a free in-browser drawing tool that produces a transparent PNG. - [How to Make a Meme Online (Free, No Watermark, No Signup)](https://uttir.com/blog/how-to-make-a-meme-online): A practical guide to making a meme in your browser: pick a template, write the top and bottom text, and download a clean image. No watermark, no signup, no upload. The right approach for a quick shareable. - [How to Create an Invoice Online Free (and Get Paid Faster)](https://uttir.com/blog/how-to-create-an-invoice-online-free): A practical guide to making a professional invoice as a freelancer or small business. What to include, the common mistakes, the right format, and a free browser-based tool that generates a clean PDF without signup, watermarks, or sending your client data to a third party. - [How to Compress an Image to a Specific File Size (Without Losing Quality)](https://uttir.com/blog/how-to-compress-an-image-to-a-specific-file-size): Need an image under 100 KB, 500 KB, or 2 MB for a form, a CMS, or an email attachment? This guide covers the practical techniques that work: quality-based compression, dimension resizing, and format conversion. Includes a free in-browser tool that does all three with a target size. - [How to Zip and Unzip Files Without Uploading Them](https://uttir.com/blog/how-to-zip-files-without-uploading-them): A practical guide to making and opening zip archives in your browser. When the in-browser approach is the right pick, when a desktop tool is better, and how to handle a multi-file batch without sending the files to a third-party server. - [How to Check if Your Password is Strong (and What "Strong" Actually Means)](https://uttir.com/blog/how-to-check-if-your-password-is-strong): A practical guide to password strength: what makes a password weak, what makes one strong, how password crackers actually work, and how to generate and remember passwords that survive a real attack. Includes a free in-browser password strength checker that never sends your password to a server. - [How to Explore a JSON File Visually (and Stop Scrolling)](https://uttir.com/blog/how-to-explore-a-json-file-visually): JSON files get long fast. A 5,000-line config file or a 50 KB API response is unreadable as raw text. This guide covers the right way to navigate a JSON document: tree views, search, path navigation, and the moves that turn a wall of text into something you can actually work with. - [How to Extract Text from Any Image (Screenshots, Scans, Photos)](https://uttir.com/blog/how-to-extract-text-from-any-image): A practical guide to pulling text out of screenshots, scanned documents, photos of signs, and PDFs. What works, what does not, when to use a browser tool, and the accuracy tips that actually matter. - [How to Make a Favicon from Any Image (in 2 minutes)](https://uttir.com/blog/how-to-make-a-favicon-from-any-image): Turn any logo, photo, or icon into a working favicon — the small image browsers show in tabs, bookmarks, and home-screen shortcuts. Free browser tool, no upload, every size and format you need. - [How to Validate an Email Address the Right Way](https://uttir.com/blog/how-to-validate-an-email-address-the-right-way): Why a regex like ^[a-zA-Z0-9._%+-]+@[a-zA-Z0-9.-]+\.[a-z]{2,}$ is not enough, what to validate server-side vs client-side, and how to catch the typos that lose you real signups. - [How to Convert an Image to Base64 (and When You Actually Should)](https://uttir.com/blog/how-to-convert-an-image-to-base64): Base64-encoded images travel as text — useful in CSS, HTML emails, JSON APIs, and anywhere you cannot ship a real image file. The trade-offs, the practical limits, and a free browser tool that does the conversion without uploading anything. - [How to Make a CSS Gradient (Linear, Radial, and Conic)](https://uttir.com/blog/how-to-make-a-css-gradient): CSS gradients are images without files. The three types, the syntax that actually matters, how to pick the right color stops, and the patterns that make any gradient look professional. - [Best Free Postman Alternatives That Run in Your Browser](https://uttir.com/blog/best-free-postman-alternatives-that-run-in-your-browser): Postman, Insomnia, Bruno, and the new wave of API clients — compared for features, privacy, and price. Includes a free in-browser API tester for one-off requests. - [TinyPNG vs In-Browser Image Compression: Privacy, Quality, and Speed](https://uttir.com/blog/tinypng-vs-browser-image-compression): TinyPNG, Squoosh, Compressor.io, and the new wave of in-browser image compressors — how they compare on quality, privacy, batch size, and price. Plus a free in-browser image compressor that never uploads your photos. - [How to Merge PDF Files Without Uploading Them Anywhere](https://uttir.com/blog/how-to-merge-pdf-files-without-uploading-them): Smallpdf, iLovePDF, Adobe Acrobat, and the in-browser alternatives — how they compare on privacy, quality, file-size limits, and price. Plus a free in-browser PDF merger that never uploads your documents. - [How to Choose the Right Image Resolution for the Web](https://uttir.com/blog/how-to-choose-the-right-image-resolution-for-the-web): Image resolution is the most common performance lever on a website. Too low and images look bad; too high and pages load slowly. This guide covers the right resolution for every use case, the math, and the format trade-offs. - [How to Validate JSON Against a Schema (And Why You Should)](https://uttir.com/blog/how-to-validate-json-against-a-schema): JSON Schema is the standard for describing the structure of JSON data. This guide covers what it is, when to use it, the basic syntax, and how to validate your data in your browser. - [How to Merge Multiple CSV Files (And Common Pitfalls)](https://uttir.com/blog/how-to-merge-multiple-csv-files): Merging multiple CSV files is a daily task for data analysts, accountants, and anyone who gets data in pieces. This guide covers the right way to do it, the common pitfalls (mismatched columns, encoding, headers), and the tools. - [How to Take a Full-Page Screenshot (Scrolling, Long Pages, Apps)](https://uttir.com/blog/how-to-take-a-full-page-screenshot): A full-page screenshot captures the entire scrollable area of a page, not just the visible viewport. This guide covers the right tool for every browser, every device, and the edge cases (sticky headers, lazy-loaded content, infinite scroll). - [How to Create a Stopwatch or Countdown Timer (Free, In Your Browser)](https://uttir.com/blog/how-to-create-a-stopwatch-or-countdown-timer): Stopwatches, countdown timers, and interval clocks are daily tools for cooking, fitness, studying, and meetings. This guide covers when to use which, the right tool, and how to build one yourself in JavaScript. - [How to Merge Multiple Images Into One PDF (And When You Should)](https://uttir.com/blog/how-to-merge-multiple-images-into-one-pdf): Combining multiple images (JPG, PNG, WebP) into a single PDF is a daily task for receipts, scans, photo albums, and document workflows. This guide covers the right way to do it, in your browser, without uploading anything. - [How to Find and Fix Broken URLs on Your Website](https://uttir.com/blog/how-to-find-and-fix-broken-urls): Broken URLs hurt SEO, frustrate users, and break the web. This guide covers how to find them (free tools, logs, search console), how to fix them (redirects, rewrites, removals), and how to prevent them in the first place. - [How to Build a Color Scheme Around Your Brand (The Practical Guide)](https://uttir.com/blog/how-to-build-a-color-scheme-around-your-brand): A brand color is one color. A color scheme is 5-10 colors that work together. This guide covers how to expand a single brand color into a complete palette using color theory, with practical examples. - [How to Test Color Contrast for Accessibility (WCAG 2.2 Explained)](https://uttir.com/blog/how-to-test-color-contrast-for-accessibility): Color contrast is the most-measured accessibility metric on the web. This guide explains the WCAG 2.2 contrast formula, the AA and AAA thresholds, and how to make sure your site is usable for people with low vision. - [What Is a URL Slug and Why It Matters for SEO](https://uttir.com/blog/what-is-a-slug-and-why-it-matters-for-seo): A URL slug is the part of a web address that identifies a specific page. This guide covers what makes a good slug, what to avoid, and how the Uttir Slug Generator handles the most common edge cases. - [What Is a PDF File and How Does It Work?](https://uttir.com/blog/what-is-a-pdf-file): A PDF (Portable Document Format) is a file format that preserves the exact appearance of a document across every device and operating system. This guide covers how it works, when to use it, and how to work with PDFs without uploading them to a server. - [What Is a Unix Timestamp and Why Do Programmers Use It?](https://uttir.com/blog/what-is-a-unix-timestamp): A Unix timestamp is the number of seconds (or milliseconds) since January 1, 1970, UTC. This guide explains why it exists, how it works, and the practical consequences — including the Y2038 problem and the 2038 bug. - [How to Compare Two Text Files (and What to Do With the Diff)](https://uttir.com/blog/how-to-compare-two-text-files): Comparing two text files is a daily task for developers, writers, and anyone who edits the same document twice. This guide covers the algorithms, the tools, and how to read a diff once you have one. - [How to Make a Color Palette from a Photo (and Why You Should)](https://uttir.com/blog/how-to-make-a-color-palette-from-a-photo): A photo is a great source for a color palette — the colors already work together. This guide covers the visual approach, the algorithmic approach, and the right tools for designers and developers. - [How to Create a Favicon for Your Website (And Why It Matters)](https://uttir.com/blog/how-to-create-a-favicon-for-your-website): A favicon is the small icon that appears in browser tabs, bookmarks, and search results. This guide shows the exact sizes, file formats, and HTML needed to add one to any site — plus a free generator that does it in your browser. - [How to Take a Screenshot on Mac, Windows, Linux, iPhone, and Android](https://uttir.com/blog/how-to-take-a-screenshot): The exact keyboard shortcuts, gesture, and tools for capturing a screenshot on every major platform. Includes scrolling screenshots, region captures, and how to annotate or extract text from a screenshot. - [How to Calculate Days Between Two Dates (and Add or Subtract Days)](https://uttir.com/blog/how-to-calculate-days-between-dates): Calculating the days between two dates, or adding days to a date, looks simple but has edge cases. Learn the rules for days, weeks, months, and years, and how to avoid the month-end and leap-year traps. - [How to Format Markdown — A Visual Cheatsheet With Examples](https://uttir.com/blog/how-to-format-markdown): Markdown is the universal plain-text format for writing on the web. Learn the syntax for every common element, see the rendered output side by side with the source, and bookmark this as a quick reference. - [How to Calculate Compound Interest (The Formula and a Spreadsheet That Works)](https://uttir.com/blog/how-to-calculate-compound-interest): Compound interest is what makes your savings grow and your debt grow faster. Learn the exact formula, how often compounding matters more than the rate, and the spreadsheet layout that lets you model any investment or loan. - [What Is CIDR Notation? A Plain-English Guide for IP Networks](https://uttir.com/blog/what-is-cidr-notation): CIDR notation (the /24 in 192.168.1.0/24) is the standard way to write IP network ranges. Learn what the slash means, how to read any CIDR block, and the practical rules for IPv4 and IPv6. - [URL Encoding Explained — What %20 and Other Percent Codes Mean](https://uttir.com/blog/url-encoding-explained-percent-encoding): URLs can only contain a small set of characters. Everything else gets percent-encoded as %XX. Learn which characters are reserved, when to encode, and the practical rules for query strings, paths, and form data. - [robots.txt Explained — A Practical Guide for Site Owners](https://uttir.com/blog/robots-txt-explained): Your robots.txt file controls which pages search engines are allowed to crawl. Learn the syntax, the most common patterns, the mistakes that can hide your site from Google, and how to write one in 60 seconds. - [How to Create an XML Sitemap (and Why You Need One)](https://uttir.com/blog/how-to-create-an-xml-sitemap): A sitemap.xml file tells search engines which pages on your site exist. Learn what to include, what to leave out, how to write one by hand or generate one, and how to submit it to Google and Bing. - [HTTP Status Codes Explained — The Full List (1xx to 5xx)](https://uttir.com/blog/http-status-codes-explained): Every HTTP status code, what it means, and what to do about it. A practical reference for the codes you actually see in production, with examples for 200, 301, 404, 500, 503, and the obscure ones you have not met yet. - [How to Read a WHOIS / RDAP Record (and What Each Field Means)](https://uttir.com/blog/how-to-read-a-whois-record): A WHOIS or RDAP record tells you who owns a domain, who runs it, and when it expires. Learn what every field means, how to look up any domain in seconds, and what to do with the information. - [What Is My IP Address — And What Does It Reveal About Me?](https://uttir.com/blog/what-is-my-ip-address-and-what-it-reveals): Your IP address is a public identifier that any website you visit can see. Learn what it exposes (city, ISP, ASN, sometimes a VPN), what it does not expose, and how to check yours without uploading anything. - [How to Compress Images Without Losing Visible Quality (2026 Guide)](https://uttir.com/blog/how-to-compress-images-without-losing-quality): Learn when JPG, PNG, WebP, and AVIF are the right choice, what quality setting to use, and the exact settings that cut file size by 70–90% with no visible difference. - [How to Merge PDF Files in the Right Order (Without Uploading)](https://uttir.com/blog/how-to-merge-pdf-files-in-the-right-order): Combine multiple PDFs into one, in any order, without uploading them to a server. Covers drag-to-reorder, bookmarks, page removal, and common pitfalls. - [How to Convert PDF to JPG (Without Losing Quality or Uploading)](https://uttir.com/blog/how-to-convert-pdf-to-jpg-the-right-way): When to convert a PDF to JPG, the right DPI setting for each use case, and how to do it for free without uploading your files. Covers whole documents and single-page extraction. - [How to Calculate Percentage Change (With Real Examples)](https://uttir.com/blog/how-to-calculate-percentage-change): The percentage change formula, worked examples for prices, grades, salaries, and growth, plus the three mistakes almost everyone makes. Includes a free calculator. - [How to Generate a QR Code for WiFi, vCard, and URLs (The Practical Guide)](https://uttir.com/blog/how-to-generate-a-qr-code-for-wifi-or-vcard): QR codes aren't just for URLs. The five practical uses that replace typing, the right QR version and error correction for each, and a free browser-based generator. - [JPG vs PNG vs WebP vs AVIF: The Right Format for Every Situation](https://uttir.com/blog/how-to-choose-the-right-image-format): A decision tree for picking the right image format, when each one wins, and the conversion paths that actually lose no quality. Includes a free browser-based converter. - [How to Validate JSON Before Deploying (The 5 Mistakes That Crash Apps)](https://uttir.com/blog/how-to-validate-json-before-deploying): JSON is forgiving to write and brutal to debug. The five validation mistakes that cause runtime crashes, the right tools to catch them, and a free browser-based validator and formatter. - [How to Calculate Reading Time (and Why 200 WPM Is a Lie)](https://uttir.com/blog/how-to-calculate-reading-time): The real reading time formula, why 200 WPM underestimates most readers, the difference between reading and speaking time, and how to use this for content planning. - [Morse Code Translator: The Complete Guide (with the Full Alphabet Chart)](https://uttir.com/blog/morse-code-translator-guide): How to read and write Morse code, the full international alphabet chart, common abbreviations, and a free browser-based translator. Plus the surprising places Morse is still used in 2026. - [How to Count Words, Sentences, and Paragraphs (and Why Each Matters)](https://uttir.com/blog/how-to-count-words-sentences-and-paragraphs): Three different counts, three different purposes. The formulas, the edge cases that trip people up, and the free tools that do it without uploading your text. - [How QR Codes Work and When to Use Them (vs Barcodes, NFC, and Links)](https://uttir.com/blog/how-qr-codes-work-and-when-to-use-them): QR codes are everywhere now, but most people do not know how they work or when to use them over a regular barcode. This guide covers the structure, the error correction, the right size, and the practical design rules. - [How to Build an Accessible Color Palette That Still Looks Good](https://uttir.com/blog/how-to-build-an-accessible-color-palette): WCAG contrast ratios depend on lightness, not hue. Learn the math, the AA and AAA thresholds, the “color is not the only signal” rule, and a workflow for testing every pairing before you commit to a palette. - [UUID v4 vs v7: When to Use Each (and Why It Matters in 2026)](https://uttir.com/blog/uuid-v4-vs-v7-when-to-use-each): UUID v7 is the 2024 successor to v4 for database primary keys. Learn what changed, why it exists, when to keep v4, and how to migrate without breaking anything. - [How to Convert HEIC to JPG Without Uploading (and Why You Should)](https://uttir.com/blog/how-to-convert-heic-to-jpg-without-uploading): Apple’s HEIC format saves storage but breaks the moment you try to share a photo. Learn what HEIC is, why it exists, how to convert it to JPG locally without uploading, and the trade-offs of every approach. - [Base64 vs Base64url vs Base32 vs Hex: When to Use Each](https://uttir.com/blog/base64-vs-base64url-vs-base32-vs-hex): Four encodings that all turn binary into text, but with different alphabets, sizes, and URL-safety. This guide explains the differences, the use cases, and the gotchas that trip people up. - [How to Learn Regex: A Beginner’s Guide (That Actually Sticks)](https://uttir.com/blog/how-to-learn-regex-beginners-guide): Regex looks like noise but it is just a tiny pattern language. This guide teaches the mental model, the most useful metacharacters, the traps, and a workflow for testing patterns without copy-pasting into random websites. - [How to Create Strong Passwords You Can Actually Remember](https://uttir.com/blog/how-to-create-strong-passwords-that-you-can-remember): A practical guide to creating passwords that are both uncrackable and memorable: passphrases, password managers, and the one rule that actually matters. Includes a free browser tool to check any password’s strength. - [How to Check DNS Records for Any Domain (and What They Mean)](https://uttir.com/blog/how-to-check-dns-records-for-a-domain): Learn what DNS records are, the most common record types (A, AAAA, MX, TXT, NS, CNAME, SOA, CAA), how to look them up from your browser, and how to use them to verify that a domain points where you think it does. - [How to Understand Standard Deviation (Without the Jargon)](https://uttir.com/blog/how-to-understand-standard-deviation): Standard deviation sounds intimidating but it is just a measure of how spread out your numbers are. Learn what it means, when to use it, and how to calculate it by hand and with a free browser tool. - [How to Write SEO Meta Descriptions That Get Clicked](https://uttir.com/blog/how-to-write-seo-meta-descriptions): A practical guide to writing meta descriptions that boost click-through rates, with length rules, examples, and a free browser tool to check yours against Google’s recommended range. - [What Is 2FA and How Does TOTP Work? A Plain-English Guide](https://uttir.com/blog/what-is-2fa-and-how-totp-works): Learn what two-factor authentication really does, how time-based one-time passwords (TOTP) work, why codes change every 30 seconds, and how to inspect your own codes without an authenticator app. - [How to Debug JWT Tokens: A Practical Guide for Developers](https://uttir.com/blog/how-to-debug-jwt-tokens): Learn what JWTs are made of, how to decode and verify them, the most common mistakes developers make, and how to inspect a token in your browser without sending it anywhere. - [The Best Free Image Tools Online: Convert, Compress, Resize Without Uploading](https://uttir.com/blog/best-free-image-tools): A curated list of the best free online image tools that run in your browser, no upload, no signup. Convert between JPG, PNG, and WebP, compress, resize, crop, and more. - [JSON vs YAML vs TOML: Which Should You Use in 2026?](https://uttir.com/blog/json-vs-yaml-vs-toml): A practical comparison of JSON, YAML, and TOML: syntax, features, readability, tooling support, and when each format is the right choice for config files, data exchange, and APIs. - [How to Merge PDF Files: 5 Free Ways (No Upload, No Signup)](https://uttir.com/blog/how-to-merge-pdf-files): Learn 5 free ways to merge PDF files into a single document, including the fastest browser-based method. No upload, no signup, no watermarks. - [How to Compress a PDF File Without Losing Quality (5 Free Methods)](https://uttir.com/blog/how-to-compress-a-pdf): Learn how to shrink a PDF file to 30-70% of its original size without visible quality loss. 5 free methods, including the fastest browser-based approach. - [Base64 Encoding Explained: What It Is and How It Works](https://uttir.com/blog/base64-explained): A practical guide to Base64 encoding: what it is, how it works, when to use it, and when to use something else. With examples and a free browser-based encoder. - [How to Resize an Image Without Losing Quality (5 Free Methods)](https://uttir.com/blog/how-to-resize-an-image): Learn how to resize images for web, email, and social media without losing quality. 5 free methods including the fastest browser-based approach. - [How is Mortgage Interest Calculated? A Plain-English Guide](https://uttir.com/blog/how-is-mortgage-interest-calculated): Learn how monthly mortgage payments are calculated, including the formula, an amortization example, and what the numbers mean for your loan. With a free mortgage calculator. - [HEX vs RGB vs HSL: Which Color Format Should You Use?](https://uttir.com/blog/hex-vs-rgb-vs-hsl): A practical comparison of HEX, RGB, and HSL color formats: when to use each, how to convert between them, and why one of them is the right choice for your next project. - [The Best Free Online Developer Tools You Can Use Without Signing Up](https://uttir.com/blog/best-free-developer-tools): A curated list of the best free online developer tools that run in your browser, no signup, no uploads, no tracking. 100 tools for formatting, encoding, testing, and more. - [How to Format JSON: A Visual Guide for Humans and Machines](https://uttir.com/blog/format-json-visual-guide): Learn what JSON formatting is, why it matters, and how to pretty-print, minify, and validate JSON. Includes common pitfalls, real examples, and a free browser-based JSON formatter. - [UUIDs Explained: v1 vs. v4 vs. v7, and When to Use Each](https://uttir.com/blog/uuid-guide): A practical guide to UUID versions — what v1, v4, v5, and v7 are, how they differ, and why UUID v7 is the right default for new database primary keys in 2026. - [Cron Expressions Explained: From "Every 5 Minutes" to Complex Schedules](https://uttir.com/blog/cron-expressions-explained): A complete guide to cron expressions: what each field means, common patterns, special characters (* ? / , -), day-of-week gotchas, and how to test your cron before shipping it. - [Image Formats Compared: JPEG vs. PNG vs. WebP vs. AVIF vs. SVG](https://uttir.com/blog/image-formats-compared): A practical comparison of JPEG, PNG, WebP, AVIF, and SVG: when to use each, how they handle transparency and animation, browser support in 2026, and how to pick the right format for the job. ## Content negotiation (for AI agents) Every page supports content negotiation. Send `Accept: text/markdown` to receive a clean, summarizable markdown rendering of any tool page, blog post, category page, or the home page. Send `Accept: text/html` (or omit the header) to receive the standard HTML. Example: ``` curl -H "Accept: text/markdown" https://uttir.com/word-counter ``` ## Discovery files - [Sitemap](https://uttir.com/sitemap.xml) — XML sitemap of every page - [LLMs.txt](https://uttir.com/llms.txt) — this file - [LLMs-full.txt](https://uttir.com/llms-full.txt) — full content dump - [RSS feed](https://uttir.com/blog/feed.xml) — blog post updates - [robots.txt](https://uttir.com/robots.txt) — crawler policy with Content Signals - [/.well-known/agents.json](https://uttir.com/.well-known/agents.json) — agent discovery - [/.well-known/security.txt](https://uttir.com/.well-known/security.txt) — security contact (RFC 9116) ## Privacy and data handling Every tool runs in the user's browser. Inputs are processed by JavaScript locally. No file or text is uploaded to a server. The only network requests are the initial page load, the static asset bundle, and the on-page ad impressions. You can verify this with the browser DevTools network panel. ## More information - [About Uttir](https://uttir.com/about) - [Press kit](https://uttir.com/press) (logos, boilerplate, brand guidelines) - [Blog](https://uttir.com/blog) - [Contact](https://uttir.com/contact) - [Privacy policy](https://uttir.com/privacy) - [Terms of service](https://uttir.com/terms) - [Sitemap](https://uttir.com/sitemap.xml) - [Agent discovery file](https://uttir.com/.well-known/agents.json) - [Machine-readable tool catalog](https://uttir.com/.well-known/tools.json)