Coin flip
Heads or tails? Click the coin for one toss, or flip a whole batch and watch the counts and streaks grow.
Ready to flip
Tally
HeadsTails
- Flips
- 0
- Heads
- 0
- Tails
- 0
- Current streak
- –
- Longest heads run
- 0
- Longest tails run
- 0
Flip a few coins to compare your longest streak with what chance usually gives.
Latest flips, oldest first
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One flip or thousands
Click the coin or press Flip once for a single toss with a short spin. For an experiment, set how many flips you want (up to 10,000 at a time) and flip them all at once: the counts, percentages and streaks update straight away and the coin shows the last result. The tally keeps adding up until you press Reset, so you can flip in batches.
Every flip takes a value from crypto.getRandomValues, your browser's cryptographic random generator, and turns it into heads or tails with exactly even odds.
Streaks are normal
People expect a fair coin to switch sides more often than it does. In 100 flips the longest run of one side averages about 7, so runs of five or six are what chance looks like, not a sign that something is broken. Under the tally you see the exact average longest streak for your number of flips, worked out by counting every possible sequence, so you can compare your run with pure chance.
Sources
- Schilling MF. The longest run of heads. The College Mathematics Journal 1990;21(3):196–207.
- Bartoš F, et al. Fair coins tend to land on the same side they started: evidence from 350,757 flips. arXiv:2310.04153 (2023).
Questions
Is an online coin flip really 50/50?
This one is: each flip has exactly even odds. Real coins come very close too, although a 2023 study of 350,757 hand flips found they land on the side that started face up slightly more often, about 50.8% of the time.
Why did I get six heads in a row?
Because it happens a lot. Any six flips in a row are all heads with a chance of 1 in 64, so over a hundred flips a run like that turns up often.
Does the coin remember earlier flips?
No. After five heads the next flip is still exactly 50/50. The streak counter only describes what has already happened.
Can I flip more than 10,000 coins?
Yes, in batches: the tally keeps adding up until you reset it. The CSV download holds the latest 100,000 flips.