Heads or Tails
Press the coin for heads or tails. Below it: the exact odds on a called run, why a streak of six proves nothing, and the small real-world bias measured over 350,757 tosses.
Flip it
Each flip is an independent 50/50 draw from your browser's random number generator. A run of five or six the same way is normal in 100 flips — that is what surprises people most.
Read this before you settle anything with it
This result decides nothing official. It is a number from your browser, not a witnessed toss – there is no record of it, no timestamp, and nothing a second person could check afterwards. If the outcome settles a bet, a dispute, or anything with money on it, toss a real coin in front of everyone involved.
The odds, exactly
One flip is heads 50%, tails 50%. Calling the same side repeatedly gets long fast: each extra flip halves the chance.
| Called in advance | Chance |
|---|---|
| Heads twice | 1 in 4 (25%) |
| Heads three times | 1 in 8 (12.5%) |
| Heads four times | 1 in 16 (6.25%) |
| Heads six times | 1 in 64 (1.56%) |
| Heads ten times | 1 in 1,024 (0.098%) |
A streak is normal, and tails is never due
Those odds are for a run you name beforehand. A run turning up somewhere in a session is far more ordinary: across twenty flips, four or more identical results in a row appear 76.8% of the time, and five or more 45.8%. Six heads does not make tails due. The next flip is still 50/50.
What a real coin does that this one cannot
A physical coin, tossed and caught in the hand, leans very slightly towards the side facing up when it left the thumb. A 2023 experiment logged 350,757 tosses and found it landed the same side it started 50.8% of the time. Heads against tails stayed level, so the bias sits in the starting position, not the coin.
Where to go next
For the same flip read as an answer, use yes or no. To watch streaks build, flip a coin 100 times, or pick a count from the coin flip page.