Flip a coin online: a fair heads or tails, and the odds behind it
By the Minigames team ·
The short answer
Our online coin flip gives heads or tails with exactly 50/50 odds. Each toss is decided by your browser’s secure random number generator, and a running tally counts heads and tails so you can play best of three or best of five. Every toss is independent: a streak of heads doesn’t make tails more likely.
- Odds
- Exactly 50% heads, 50% tails
- Randomness
- Browser’s secure random number generator
- Extras
- Running tally, resettable
- Cost
- Free, no app or account
How to flip
- 1Open the coin. Open the coin flip on any phone or computer.
- 2Call it. Have someone call heads or tails before the toss.
- 3Flip. Tap the coin or the Flip button. The result shows when the coin lands.
- 4Check the tally. The tally at the top counts every result. Reset it in the settings.
Is an online coin flip fair?
Ours is. Each toss takes a random byte from the browser’s cryptographic random number generator, the same source used for security keys. A byte has 256 possible values, exactly half even and half odd, so heads and tails are precisely 50/50 with no rounding bias.
A real coin is very close to fair, but not perfectly. A large 2023 study of more than 350,000 hand-flipped tosses found coins landed on the side that started facing up about 51% of the time. A virtual coin has no starting side.
Coin flip odds
Each toss is independent, so past results never change the next one. Streaks are more common than most people expect:
| Event | Chance |
|---|---|
| Heads on one toss | 50% |
| Two heads in a row | 25% |
| Five heads in a row | 1 in 32 (3.1%) |
| Ten heads in a row | 1 in 1,024 (0.1%) |
| A run of 3 or more of the same side in 10 tosses | About 83% |
Thinking tails is “due” after a run of heads is called the gambler’s fallacy. The coin has no memory.
Best of three, best of five
For a bigger decision, use the tally. In best of three, the first side to two wins; in best of five, the first to three. Longer matches don’t change who is favoured, since each side still has an even chance, but they feel fairer to the loser.
When to use a coin, and when not to
A coin is perfect for two options: who goes first between two players, which team kicks off, or settling a choice between two restaurants. With three or more players, a coin needs several rounds of elimination; the finger chooser picks one person in a single go.
Frequently asked questions
Is an online coin flip really 50/50?
Ours is exactly 50/50. Each toss uses a random byte from the browser’s secure random number generator, and half of the 256 possible values give heads.
After five heads in a row, is tails more likely?
No. Every toss is independent, so the next toss is still 50/50. Believing otherwise is the gambler’s fallacy.
How do you do best of three with a coin?
Flip until one side has won twice. The running tally at the top of the coin flip keeps count.
Can I flip a coin without an app?
Yes. The coin flip runs in any browser, free and without an account.