Flip a virtual coin for decisions, games, or probability experiments. Flip once for a single result or flip multiple times to see how often heads vs. tails appears.
| Streak | Probability |
|---|---|
| 2 heads in a row | 25% |
| 3 heads in a row | 12.5% |
| 5 heads in a row | 3.125% |
| 10 heads in a row | 0.098% |
Each flip is independent: the coin has no memory. After five heads in a row, the next flip is still 50/50. The coin does not know what it did before and is not "due" for tails.
Believing otherwise is the gambler's fallacy, and it is remarkably persistent — it underpins a great deal of bad betting and some bad investing.
Streaks feel surprising but are statistically expected. In 100 flips, a run of six or seven identical results is more likely than not.
People asked to fake a random sequence almost always alternate too much, producing fewer long runs than genuine randomness does. This is how fabricated data is often detected — it looks too tidy.
The proportion of heads approaches 50% as flips accumulate. The absolute difference between heads and tails tends to grow, not shrink.
After 10,000 flips you might be 60 ahead on heads — a larger gap than after 100 flips, yet a proportion of 50.6%, much closer to half. Averages converge; counts drift. Mixing these up is behind the belief that results must "even out" in absolute terms.
| Outcome | Probability |
|---|---|
| 2 heads in a row | 25% |
| 3 heads in a row | 12.5% |
| 5 heads in a row | 3.1% |
| 10 heads in a row | 0.098% |
Each additional flip halves the probability, since outcomes multiply: 0.5 raised to the number of flips.