Coin Flip — Heads or Tails
Flip a virtual coin and get heads or tails instantly.
- Heads
- 0
- Tails
- 0
- Total flips
- 0
- Heads %
- —
The more you flip, the closer heads should drift toward 50% — the law of large numbers.
A coin flip has two equally likely outcomes — heads or tails — each with a 50% (½) chance on a fair coin. Click Flip for a random result, flip up to ten coins at once, or keep flipping to watch the running heads count settle toward 50%, showing the law of large numbers in action.
How a fair coin works
A fair coin has exactly two outcomes, heads and tails, and each is equally likely: the probability of heads is ½, or 50%, and the same for tails. This tool draws each result from your browser’s built-in randomness, so every flip is an independent 50/50 draw. There is no bias toward the side that came up last time.
Every flip is independent
Coins have no memory. The result of one flip has no effect on the next, so the odds stay 50/50 on every single throw no matter what came before. A run of five heads does not make tails “due” — the next flip is still an even chance. Believing otherwise is the gambler’s fallacy: the mistaken idea that past results change the probability of an independent event.
The law of large numbers
Independence does not mean the totals stay lopsided. Over many flips, the share of heads tends to drift toward 50% — this is the law of large numbers. In a handful of flips you can easily see 70% heads, but after hundreds of flips the percentage usually hugs 50% closely. Watch the running tally above climb: with more flips the heads % settles down, even though any one flip is still a coin toss.
Flipping several coins at once
Because flips are independent, the chance of a specific sequence multiplies. Two heads in a row is ½ × ½ = ¼ (25%), three in a row is (½)³ = 12.5%, and in general the chance of getting n heads in a row is (½)ⁿ. The table below shows how quickly a clean streak becomes unlikely.
Probability of a run of heads
Each result is independent, so the odds of n heads in a row multiply as (½)ⁿ.
| Outcome | Probability | As a fraction | Percent |
|---|---|---|---|
| 1 head | (½)¹ | 1 in 2 | 50% |
| 2 heads in a row | (½)² | 1 in 4 | 25% |
| 3 heads in a row | (½)³ | 1 in 8 | 12.5% |
| 4 heads in a row | (½)⁴ | 1 in 16 | 6.25% |
| 5 heads in a row | (½)⁵ | 1 in 32 | 3.125% |
| 10 heads in a row | (½)¹⁰ | 1 in 1024 | ≈ 0.098% |
The same maths works for tails, or for any exact ordered sequence of heads and tails of length n — each specific sequence has probability (½)ⁿ. What changes is how many sequences give the same count: there is only one way to get all heads, but several orderings that give, say, three heads out of five, which is why mixed results are more common than a perfect streak.