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Coin Flip

Flip a virtual coin for heads or tails.

Tap to flip

Press Space or Enter to flip again.

Your flips

Heads
0
Tails
0
Streak
0

Flip many at once

When to use it

Use this coin flip when you need a quick, fair 50/50 decision: who goes first in a game, which restaurant to pick, who does the dishes, or settling a tie. Teachers also use it to show probability in class, and the many-coins option makes it easy to see how results even out over thousands of flips.

How to use it

  1. Tap the coin or press Flip coin. The coin spins and lands on Heads or Tails.
  2. Press Space or Enter to flip again.
  3. Check Your flips to see the totals for heads and tails and the current Streak.
  4. Press Reset to start counting again.
  5. To flip lots at once, enter the Number of coins under Flip many at once and press Flip.

Worked example

Two friends cannot decide who drives. They agree heads means Alex and tails means Sam, then tap the coin. It lands on tails, so Sam drives.

In a maths lesson, a teacher flips 10 coins with the many-coins option and gets 7 heads and 3 tails, which surprises the class. Then she flips 10,000 coins, and the result is very close to half and half, perhaps 5,031 heads and 4,969 tails. This shows that small samples vary a lot, while large samples settle near the true probability.

Probability facts

  • Every flip has a 1 in 2 chance of heads, no matter what came before.
  • The chance of 3 heads in a row is 1 in 8, and 10 in a row is about 1 in 1,024.
  • Over many flips, the share of heads gets close to 50%, but the difference in raw numbers can still grow.

Tips

  • Agree the outcome first. Decide out loud what heads and tails mean before flipping.
  • Use best of three for big decisions. It feels fairer if someone does not like the first result.
  • Notice your reaction. If you hope for one side while the coin spins, that tells you what you really want.

Common mistakes

  • Believing a result is “due”. After five tails, heads is still only 50% likely. This mistake is called the gambler’s fallacy.
  • Changing the rules after the flip. Agree beforehand, and stick to it.
  • Using a small sample to test fairness. Ten flips tell you very little. Flip a few thousand coins at once to see the real pattern.

Frequently asked questions

Is the coin flip really random?

Yes. It uses your browser's cryptographic random number generator, which gives heads and tails an equal 50% chance on every flip. Each flip is independent of the ones before it.

I got heads five times in a row. Is something wrong?

No. Streaks are a normal part of randomness. Five heads in a row has about a 1 in 32 chance, so over many flips it happens quite often. The Streak counter shows how long the current run is.

Can I flip many coins at once?

Yes. Under Flip many at once, enter a number of coins from 1 to 10,000 and press Flip to see how many came up heads and tails.

Can I use the keyboard?

Yes. Press Space or Enter to flip again.

Is it fair to use for real decisions?

It is as fair as a real coin, and arguably fairer, since a real coin can be slightly biased by how it is tossed. Agree what heads and tails mean before you flip.

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