How to Generate a QR Code for WiFi, vCard, and URLs (The Practical Guide)

QR codes used to be a novelty. Now they're the fastest way to hand someone a WiFi password, a contact card, or a link to your business — without anyone typing anything. This guide covers the five practical uses that replace real typing, the right QR version and error correction for each, and a free browser-based generator that handles them all.

If you just need to generate a QR code right now, the Uttir QR Code Generator does it in your browser. The codes never touch a server.

The five QR codes that actually matter

Most "QR code uses" lists are padded with trivia. In real life, five formats cover almost every useful case.

1. URL QR codes (the default)

The most common QR code is a URL. When scanned, the phone opens the link in the browser. Use it for:

• Business cards — link to your portfolio, LinkedIn, or booking page.
• Restaurant menus and table tents.
• Flyers, posters, and product packaging.
• WiFi networks (yes, this is its own format, but you can also just put a WiFi-setup-URL).

The format is just the URL itself: https://example.com/your-page. No wrapping, no protocol prefix other than https://. Most QR generators treat anything starting with http as a URL automatically.

2. WiFi QR codes

The format for a WiFi network is:

WIFI:T:WPA;S:network-name;P:password;H:false;;

Where:

• T:WPA — the security type (WPA, WEP, or nopass for open networks).
• S:network-name — the SSID, exactly as it appears in the network list.
• P:password — the WiFi password.
• H:false — whether the network is hidden (usually false).

When scanned, the phone prompts the user to join the network. No typing the password, no mis-typed characters. This is the single most useful QR code for any business that offers guest WiFi — cafes, salons, co-working spaces, Airbnbs.

Special characters in the SSID or password need to be escaped: becomes \\, ; becomes \;, , becomes \,, : becomes \:, and " becomes \". Most QR generators handle this automatically — including the Uttir QR Code Generator.

3. vCard QR codes

A vCard is a standard format for contact information. When scanned, the phone offers to add the contact. The format (vCard 3.0) looks like:

BEGIN:VCARD VERSION:3.0 FN:Ada Lovelace ORG:Analytical Engine Co. TITLE:Programmer TEL;TYPE=WORK,VOICE:+44-20-1234-5678 EMAIL:[email protected] URL:https://example.com END:VCARD

All the fields are optional except FN (formatted name) and VERSION. The phone stores whatever fields you include.

Use it on business cards so a recipient can add you as a contact in one scan instead of typing each field. The Uttir QR Code Generator has a vCard mode that produces this format with a simple form.

4. Email QR codes

The format for pre-filling an email is:

mailto:[email protected]?subject=Hello&body=Message%20here

When scanned, the phone opens the user's mail app with the recipient, subject, and body pre-filled. Useful for "email us to subscribe" or "report a problem" links that you want to remain a single scan.

5. SMS QR codes

The format is:

sms:+15551234567?body=Hello

Phone opens the SMS app with the recipient and body pre-filled. Used for "text us to win" campaigns and similar.

Error correction: pick the right level

QR codes have four error-correction levels, from lowest to highest resilience:

Level	Name	Recovery	Use when
L	Low	~7%	Clean digital display, pristine print, no logo overlay.
M	Medium	~15%	Default for most uses. Good balance of size and resilience.
Q	Quartile	~25%	Outdoors, possible smudges, or you want a small logo in the middle.
H	High	~30%	Harsh environments, dirty surfaces, or large center logo.

Use H when you'll print the code and want to overlay a logo in the center. The logo replaces some of the modules, and H ensures the code still scans even with up to 30% of the pattern obscured.

Size and print: the right minimum

The rule for scannable print is: the smallest module in the QR code should be at least 0.4 mm (1/64 inch) at print size. Anything smaller fails on cheap cameras.

Practical minimums:

• Business card — 2 × 2 cm (0.8 × 0.8 in). Works fine.
• Poster (A2) — 10 × 10 cm. Plenty of margin.
• Billboards — scale up so that the viewing distance is at least 10× the QR's height.
• Phone screen — 200 × 200 px minimum for an on-screen code (bigger is better).

The Uttir QR Code Generator lets you set the pixel size, the error-correction level, and the foreground/background colors. All combinations produce a scannable code as long as contrast is high.

Common mistakes

Low contrast colors

QR codes need high contrast between foreground and background. Black on white is the safe default. If you want a colored code, the foreground must be much darker than the background — a light-gray-on-white code often fails in bad lighting. Avoid red-on-black or any combination where the two colors are similar in brightness.

Center logos that are too big

You can put a small logo in the center of a QR code, but it covers some of the modules. With error correction H, you can lose 30% of the modules and still scan. Keep the logo under 25% of the code's width to be safe.

Trying to encode a huge URL

QR codes have a maximum capacity (~3 KB binary, ~7 KB alphanumeric). Long URLs work but require a higher version (more modules), which makes the code denser and harder to scan. If your URL is over 100 characters, consider using a short link first (bit.ly, yourdomain.com/s/abc), then encoding the short version.

Forgetting to test the printed code

Always test the printed QR code with multiple phones before mass-printing. Different phones have different cameras and different default zoom behaviors. The QR may scan on your phone but fail on older models.

Privacy and tracking

Static QR codes (like the ones the Uttir QR Code Generator produces) are just images. They don't phone home, they don't track scans, and they don't require any service to work after generation.

Dynamic QR codes (from services like Bitly, Beaconstac, or QR Code Generator Pro) are different — they encode a redirect URL, and the service tracks every scan. Convenient for analytics, but it means the service must stay online forever for the code to keep working, and the operator can see who's scanning and when.

For business cards, WiFi, and vCards, static is the right answer. The codes work forever, with no third party involved.

FAQ

Do QR codes expire?

Static QR codes (which the Uttir QR Code Generator produces) never expire. The data is encoded in the image itself, so it works as long as the image is intact. Dynamic QR codes (from paid services) can expire if the service shuts down or your subscription lapses.

Can I put a logo in the center?

Yes, with the right error-correction level. Use H (30% recovery) and keep the logo under 25% of the code's width. The Uttir QR Code Generator outputs the code; you can overlay a logo in any image editor.

What's the best size for a phone screen?

200 × 200 px minimum, but 400 × 400 px is more reliable across devices. If the code is part of a webpage and you control the layout, make it at least 1.5 × 1.5 inches (38 × 38 mm) on screen.

Can a QR code store an entire vCard with a photo?

Yes, but the photo eats capacity fast. A vCard with a 50 KB photo can push the code to version 20 or higher, which makes it dense and harder to scan. For visual recognition, use the photo on the card itself and let the QR handle the data fields.