# Coin Flip

> Flip a virtual coin or roll dice. Cryptographically fair randomness, runs in your browser, history tracked per session.

URL: https://uttir.com/coin-flip
Categories: generators, math-tools
Privacy: Every flip and roll uses your browser's cryptographically-secure random number generator. Nothing is sent to a server.

## About

A virtual coin flip and dice roller that uses the browser's cryptographically-secure random number generator. The result is unpredictable until the moment of the flip — no time-based trick, no pre-computed sequence. The session tracks how many heads vs tails you have seen, so you can verify the distribution over many flips.

For coin flips, the answer is heads or tails with equal probability. For dice, the supported types are d4, d6, d8, d10, d12, d20, and d100. You can roll multiple dice at once and the tool shows each individual result plus the total.

## How to use

1. **Click "Flip the coin"** — The coin rotates for a moment, then lands on heads or tails with equal probability.
2. **Pick dice type and count** — Choose the number of dice and the number of sides (d4, d6, d8, d10, d12, d20, d100).
3. **Roll and read the result** — Each die shows its face. The total appears next to the individual rolls.

## Examples

### Quick decision

Heads we eat out, tails we cook at home.

Output:

```
Heads — you eat out tonight.
```

### Tabletop RPG attack roll

Roll 1d20 + 5 to hit.

Output:

```
Roll the d20, add 5. 18+ hits most AC values.
```

### Multiple dice

Roll 3d6 for a D&D ability score.

Output:

```
Sum the three results. The total is between 3 and 18, with an average of 10.5.
```

## FAQ

### Is the coin flip really random?

Yes. The result is drawn from the browser's cryptographically-secure random number generator, which is the same API used for TLS connections and password generation. The result is not based on the time of the click or any other predictable signal.

### What dice types are supported?

d4, d6, d8, d10, d12, d20, and d100. You can roll 1-20 dice at a time. The result for each die is independent; rolling 3d6 is equivalent to rolling one d6 three times and summing the results.

### Why is the distribution not exactly 50/50?

Over a small number of flips, the heads/tails split is unlikely to be exactly even. Over 100 flips, the split is almost always between 40/60 and 60/40; over 1,000 flips, the split is almost always between 47/53 and 53/47. The expected split is 50/50, but the observed split converges to that only over many trials.

### Is the result sent anywhere?

No. The flip runs entirely in your browser. The history (heads/tails count) is in the page and resets when you close the tab.

## Related tools

- [Random Number Generator](https://uttir.com/random-number-generator) — Pick a random number, roll dice, or shuffle a list. Cryptographically secure, runs locally.
- [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.
- [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.

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For the full HTML page with the live tool, visit https://uttir.com/coin-flip.
This file is the markdown rendering at https://uttir.com/coin-flip.md. See https://uttir.com/llms.txt for a site-wide summary.