How to flip the coin
Tap the coin or press Flip once. The coin spins and lands on H for heads or T for tails. Press Flip 10 times or Flip 100 times to run a batch in one go and see how the results spread out.
Every flip is added to the tally: the number and percentage of heads and tails, the total number of flips, your current streak and the longest streak so far. The strip at the bottom shows your last 100 flips in order. Reset clears everything.
The odds of a coin flip
A fair coin has two equally likely sides, so each flip is a 1 in 2 chance, or 50%. The coin has no memory. After five tails in a row, the next flip is still exactly 50/50. Believing that heads is now "due" is called the gambler’s fallacy, and it is one of the most common mistakes people make with chance.
Streak math
To get the chance of a run, multiply one half by itself once for each flip:
| Heads in a row | Chance |
|---|---|
| 2 | 1 in 4 (25%) |
| 3 | 1 in 8 (12.5%) |
| 5 | 1 in 32 (about 3.1%) |
| 7 | 1 in 128 (about 0.8%) |
| 10 | 1 in 1,024 (about 0.1%) |
Those numbers are for a run starting right now. Over a long series, streaks are much more common than most people expect. In 100 flips, a run of six or seven of the same side somewhere in the sequence is normal. Try Flip 100 times a few times and watch the longest streak: it rarely stays below 5.
Why the percentages wobble
After 10 flips, 7 heads and 3 tails is not unusual at all. As the number of flips grows, the share of heads moves closer to 50%. This is the law of large numbers. The gap in raw counts can still grow, though: after 1,000 flips you might be 20 heads ahead and still be at 51%.
Real coins vs this coin
Real coin tosses are close to fair but not perfect. Researchers who studied hand tossed coins in detail found a slight tendency to land on the side that started facing up, roughly 51 times in 100. A virtual flip has no starting side and no thumb, so it stays at an even 50%.
Ways to use a coin flip
- Decide who goes first or who picks the side in a game.
- Break a tie between two equally good choices.
- Teach probability: have a class predict the longest streak in 100 flips, then check.
- Settle a friendly bet quickly and fairly.
Want a third option or a best of 3? Try the Yes or No Wheel. Need more than two outcomes? The Dice Roller covers anything from 4 to 100 sides.
Questions
Is this coin flip really 50/50?
Yes. Each flip uses your browser’s cryptographic random number generator, so heads and tails each have exactly a 50% chance, and no flip depends on the one before.
What are the odds of getting 5 heads in a row?
The chance of 5 heads in a row is 1 in 32, about 3.1%, because you multiply one half by itself five times. Ten heads in a row is 1 in 1,024.
Why don’t I get exactly 50 heads in 100 flips?
Exactly 50 heads in 100 fair flips happens only about 8% of the time. Results between 40 and 60 heads are normal. The share of heads gets closer to 50% as you flip more, but the raw counts can still drift apart.
Is my tally saved?
Your counts are saved in your own browser so they survive a page reload. Press Reset to start a new tally.