Coin Flip
Runs entirely in your browser. Nothing is sent to a server.
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Keep Coin Flip handy
Use your browser's Share menu, then “Add to Home Screen”.
Flip a coin online, heads or tails, in your browser.
- Choose heads or tails in your head first
- Click Flip
- Flip again as many times as you like — the tally keeps count
About this tool
A coin flip is the fairest way to settle something small, provided the coin is actually fair. This one draws from your browser's cryptographic random source and discards draws that would tilt the odds, so heads and tails are exactly as likely as each other. That sounds like a technicality until you remember what the tool is for: nobody minds losing a fair toss, and a coin that quietly favours one side is worse than no coin at all. Flip once to decide something, or flip a few hundred times and watch the tally settle towards even, which is the only way to see fairness rather than take it on trust. You can also weight the coin deliberately if you want odds rather than a decision. Everything runs locally, so no flip is transmitted, logged, or stored, and refreshing the page starts a fresh count.
Frequently asked questions
Is this coin actually fair?
Yes. It uses the Web Crypto API rather than the ordinary scripting random function, and discards the small number of draws that would otherwise make one side very slightly more likely. Over a few hundred flips you should see the tally sit close to even.
Is the result decided before I click?
No. The draw happens when you click, in your browser. Nothing is pre-generated and nothing is sent anywhere, so there is no result sitting on a server waiting for you.
Why does it show a running tally?
Because one flip tells you nothing about whether a coin is fair and a hundred tells you almost everything. It also makes re-flipping visible, which is the honest failure mode of any coin: flipping until you get the answer you wanted.
Can I flip more than one coin at a time?
Yes. Set how many flips you want and they are all drawn at once, up to a thousand. Each is independent, so a run of heads is normal rather than a sign of anything.
What is the chance-of-heads setting for?
It weights the coin on purpose, for when you want odds rather than a fair decision — a one-in-four chance, say. Leave it at 50 for an ordinary coin.
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