Coin Flip
Tap the button to flip a virtual coin with a cryptographically random result and a running tally of heads and tails.
Press Flip to toss the coin
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Heads · 0.0%
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Tails · 0.0%
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Total flips
Results use crypto.getRandomValues and never leave your browser.
How it works
- Press the Flip button to toss the coin and watch it spin to heads or tails.
- Use Flip 10 or Flip 100 to run many tosses at once and see the aggregate result.
- Check the tally below for counts and percentages, and press Reset stats to start over.
Frequently asked questions
- Is this coin flip really random?
- Yes. Each toss uses your browser’s crypto.getRandomValues function, the same cryptographic random source used for generating encryption keys. Unlike Math.random, it draws from operating-system entropy, so results are unpredictable and unbiased at exactly 50/50 odds.
- Can I flip more than one coin at a time?
- Yes. The Flip 10 and Flip 100 buttons run that many independent tosses instantly and add them all to your running tally. This is handy for probability experiments, classroom demonstrations, or simply checking that the results converge toward 50% over many flips.
- Does the coin flip work offline or send data anywhere?
- Everything runs entirely in your browser with no network requests. Once the page has loaded, you can flip coins without an internet connection, and none of your results are recorded or sent to any server.
- Why isn’t my heads/tails split exactly 50/50?
- Short runs naturally drift from the theoretical average — getting 7 heads in 10 flips is common. This is normal statistical variance, not bias. As your total number of flips grows into the hundreds, the percentages will settle much closer to 50% for each side.
- What can I use a coin flip for?
- Anything that needs a fair binary decision: settling who goes first in a game, breaking a tie, choosing between two options, or teaching probability. Because the result is cryptographically random, neither party can predict or influence the outcome.
About this tool
This coin flip tool gives you a fair heads-or-tails result in one tap, with a simple animated coin so you can see the toss happen rather than just reading a word on the screen. It keeps a running tally of every flip in your current session, showing counts and percentages for heads and tails so you always know how your run is going.
Under the hood, each toss calls crypto.getRandomValues, the cryptographically secure random number generator built into every modern browser. It pulls entropy from your operating system, which makes each result genuinely unpredictable — a meaningful step up from the pseudo-random Math.random function most virtual coins rely on. All of this happens locally on your device: no network request is made, nothing is logged, and your flip history disappears when you close the tab.
The batch buttons make the tool useful beyond quick decisions. Flip 10 or Flip 100 runs that many independent tosses at once and folds them into your totals, which is ideal for probability lessons: students can watch a small sample swing wildly — say, 65% heads after 20 flips — then see the split tighten toward 50/50 as the sample grows. It is a hands-on demonstration of the law of large numbers that takes seconds instead of an afternoon of tossing real coins.
For everyday use, keep it simple: one tap settles who kicks off, who picks the restaurant, or which of two options wins. If a decision matters enough that you would argue about a real coin landing on its edge, agree beforehand which side means what, flip once, and accept the result — the randomness here is as fair as it gets.