Is this coin flip fair?

Yes. Heads and tails are each chosen from a single secure random bit, so each has a 50% chance on every flip.

What are the odds of getting heads several times in a row?

The chance of n heads in a row is 1 in 2^n: 25% for two, 12.5% for three, about 3.1% for five and about 0.1% for ten.

Why do I see long streaks if it is 50/50?

Streaks are normal in random sequences. In 100 flips a run of five or more of the same side is likely. That is variance, not a sign of a broken coin.

Can I flip more than one coin?

Yes. Choose up to 10 coins per flip, and up to 1000 flips per click.

Random · Decision

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Need heads or tails? Flip one coin or up to ten at once, then see the result, streak and running history immediately.

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Result

Press Flip coin to begin.

How this coin flip works

Each coin takes one random bit from crypto.getRandomValues(), the browser's cryptographically secure generator: 0 is tails, 1 is heads. Each flip is independent, with no bias and no memory, so a streak never makes the opposite side “due”. Everything runs in your browser and nothing is sent anywhere. Your tally is kept in this browser's local storage until you press Reset stats.

Worked examples

Settling a choice: call heads or tails first, then flip one coin. Best of three is just three single flips.
Several coins at once: set Coins per flip to 3 and you get three results together. All three landing heads has a chance of (1/2)×(1/2)×(1/2) = 1 in 8, or 12.5%.
Watching the average settle: set Flips per click to 1000. The split usually lands near 50/50, typically within a few percentage points, though the raw gap in counts tends to grow.

Frequently asked questions

Is this coin flip fair?: Yes. Heads and tails are each chosen from a single secure random bit, so each has a 50% chance on every flip.
What are the odds of getting heads several times in a row?: The chance of n heads in a row is 1 in 2ⁿ: 25% for two, 12.5% for three, about 3.1% for five and about 0.1% for ten.
Why do I see long streaks if it is 50/50?: Streaks are normal in random sequences. In 100 flips a run of five or more of the same side is likely. That is variance, not a sign of a broken coin.
Can I flip more than one coin?: Yes. Choose up to 10 coins per flip, and up to 1000 flips per click.

Need something other than two outcomes? Try the dice roller, the random number generator or the wheel spinner.