About the Coin Flip
Flipping a coin is the simplest fair way to choose between two options โ picking ends at kick-off, deciding who goes first or settling where to eat. Results come from your browser's cryptographic random generator (crypto.getRandomValues), so heads and tails each have exactly a 50% chance.
Rename the sides, for example to "Pizza" and "Tacos", and the result shows those names. Your stats are stored only on this device.
How to use
- Press Flip a coin or tap the coin. On a computer you can also select the coin and press the space bar.
- When the coin stops spinning, the side facing up is the result.
- Want to see probability in action? Use Flip 10 times or Flip 100 times and watch the ratio.
- Rename heads and tails below if you like. Reset stats starts the counts from zero.
Chances of a heads streak
A coin has no memory, so every flip is 50% heads. But the chance of the same side several times in a row drops fast.
| Streak | Math | Chance |
|---|---|---|
| 2 heads in a row | (1/2)ยฒ | 25% |
| 3 heads in a row | (1/2)ยณ | 12.5% |
| 5 heads in a row | (1/2)โต | 3.125% |
| 10 heads in a row | (1/2)ยนโฐ | about 0.098% |
Still, in 100 flips it's common to see a run of 5 or more of the same side at least once. A long streak isn't suspicious.
Why more flips get closer to 50%
With only 10 flips, results like 7 heads and 3 tails are common. As the number of flips grows, the share of heads moves closer to 50% โ the law of large numbers. In 100 flips, the chance of getting between 40 and 60 heads is about 96%. Press Flip 100 times a few times to see it yourself.
FAQ
Can the result be rigged?
No. The result is decided by your browser's cryptographic random generator the moment you press the button; the spin is only animation. Nothing goes through a server, so no one else can change it.
Is a real coin exactly 50/50?
Almost, but not perfectly. Research shows a hand-flipped coin lands on the side that started face up slightly more often (about 51%). This tool is exactly 50% with no bias.
Which side of a US coin is heads?
Heads is the side with the portrait (for example Lincoln on the penny or Washington on the quarter); tails is the reverse. In this tool the gold side is heads and the silver side is tails.
Where are my stats stored?
Flip counts and recent results are stored only in your browser and never sent to a server. Reset stats deletes them.