Flip a coin

Heads or tails, and nothing else

Call it, then tap. The coin is our own design: a crown on the heads side and a five on a die for tails, so there is never a doubt which side came up. Your counts and history stay in this browser so a running tally survives a reload; clear them with the button under the history.

For a game, best of 3 is the usual way to settle a dispute that a single toss would leave someone grumbling about. Pick a mode and toss until the page names a winner.

How each toss is decided

The result is chosen before the coin starts to turn. Your browser's cryptographic random generator (crypto.getRandomValues, the source used for security keys) hands over a large random number. The page keeps it only if it falls in a range that divides evenly into two halves, which rules out the small lean a plain remainder can cause, and draws again otherwise. The spin you see then lands on the side already picked. If your device asks for reduced motion, the coin shows the result straight away.

A real coin is very slightly biased. Researchers who recorded 350,757 hand tosses found the coin landed on the side it started on 50.8% of the time (Bartoš and others, 2023). For a close call, a toss with no starting side is the fairer one.

The automated tests behind this page toss 100,000 coins and check heads stays within 1% of half, and that streak lengths look like a fair coin's.

Coin flip questions

Is this coin really 50/50?

Yes. Each toss reads a fresh number from your browser's cryptographic random source and keeps only values that split evenly into two, so heads and tails have exactly the same chance every time. Earlier results have no effect on the next one.

Is a real coin toss fair?

Close, but not quite. In a 2023 study of 350,757 recorded hand tosses, the coin landed on the side it started on 50.8% of the time. That is a tiny edge, but it is there. This page has no starting side, so it does not have that lean.

I got heads six times in a row. Is something wrong?

No. Runs like that are normal. In 100 tosses of a fair coin, the longest run of one side is usually somewhere around six or seven. Watch the "longest run" numbers under the coin: they grow just as a fair coin's should.

How does best of 3 work?

Choose best of 3, 5 or 7 and keep tossing. The first side to win a majority (2 of 3, 3 of 5, 4 of 7) takes the series and the page names the winner. Your next toss starts a fresh series, or press "Start a new series" to reset the score early.

Can I toss more than one coin?

Yes, up to 10 at once. Each coin is a separate fair toss, and the page totals the heads and tails for you. Multiple coins are turned off during a best-of series so the score stays simple.