How to flip a coin online
Leave the number of coins at 1 and press Flip: the big box shows Heads or Tails. Press Flip again for a new toss. To settle something fairly, agree who has heads before anyone presses the button. Set the number to 10, 100 or 1,000 to toss many coins at once — the result shows the heads and tails counts, the longest run of the same side, and a list of every flip.
Is it really 50/50?
Each virtual coin is the lowest bit of a random byte from crypto.getRandomValues, the secure generator built into your browser, so heads and tails have exactly equal chances and no toss depends on the one before. That is fairer than a real coin. In 2007, Persi Diaconis, Susan Holmes and Richard Montgomery showed that a hand-flipped coin wobbles in the air and tends to land on the side that was facing up when it was tossed, and predicted about a 51% bias. A 2023 experiment led by František Bartoš at the University of Amsterdam tested it with 350,757 real flips by 48 people and found coins landed on their starting side 50.8% of the time. The bias is small, but this page has none.
What results are normal?
Fair does not mean perfectly even. With 10 coins, getting exactly 5 heads happens only about 25% of the time; anything from 2 to 8 heads is ordinary. The calculator works out the exact binomial range that holds at least 95% of outcomes for your number of coins, so you can see whether a run is unusual:
- 10 coins: 2 to 8 heads (97.9% of the time)
- 100 coins: 40 to 60 heads (96.5%)
- 1,000 coins: 469 to 531 heads (95.4%)
As the number of coins grows, the heads share settles closer to 50% — the law of large numbers — even though the raw difference between heads and tails usually grows.
Streaks are more common than you think
People expect coins to alternate, but long runs are normal. In 100 tosses the longest run of the same side is usually about 7. The chance that the next k tosses all come up heads:
| Heads in a row | Odds | Chance |
|---|---|---|
| 2 | 1 in 4 | 25% |
| 3 | 1 in 8 | 12.5% |
| 4 | 1 in 16 | 6.25% |
| 5 | 1 in 32 | 3.13% |
| 7 | 1 in 128 | 0.781% |
| 10 | 1 in 1,024 | 0.098% |
After five heads in a row, the next toss is still 50/50. Believing tails is “due” is the gambler’s fallacy: the coin has no memory.
Fair ways to use a coin toss
- Best of three: if a single toss feels too abrupt, the first to win two tosses takes it.
- Fair result from a biased coin: John von Neumann’s trick — toss twice; heads-tails means A wins, tails-heads means B wins, and a double result means toss twice again. It works because both mixed outcomes are equally likely even for a lopsided coin.
- More than two options: use the spin the wheel picker, or roll a die with the dice roller.
Frequently asked questions
Is heads or tails more likely?
Neither. On this page each side has exactly a 50% chance. With real coins there is no heads-versus-tails preference either; the only measured effect is a slight tendency (about 50.8%) to land on the side that started face up.
Can I flip more than one coin?
Yes — enter any number from 1 to 1,000. You get the heads and tails counts, the longest streak, the normal range and the full list of results in groups of ten.
Why did I get so many heads in a row?
Streaks are a normal part of randomness. Three heads in a row happens 1 time in 8, and in 100 tosses a run of 6 or more is typical. Each toss is independent of the ones before.
Is an online coin flip as good as a real one?
For fairness, it is better: a real coin carries a small physical bias, while this one is an exact 50/50 from a cryptographically secure generator. It just isn’t as satisfying to catch.
Last updated: October 14, 2026