Coin Flip - Heads or Tails with a Tally, Streaks and up to 1,000 Coins
Flip a coin and get heads or tails, with a running tally of both, the percentage of each and a streak counter that shows the current run and the longest run.
Maintained by Hirantha Sandaruwan Lakshan. Updated 15 October 2026.
About this tool
Flip up to 1,000 coins at once to see how a fair coin really behaves. Every flip comes from your browser's secure random number generator and gives each side exactly a 50% chance.
How it works
Each coin is one draw of 0 or 1 from crypto.getRandomValues: 0 is heads and 1 is tails. A range of two divides the 4,294,967,296 possible 32-bit values exactly, 2,147,483,648 for each side, so no random value has to be thrown away and the way the number is turned into a flip favours neither side.
A real coin is not exactly 50/50. Diaconis, Holmes and Montgomery (SIAM Review, 2007) showed that vigorously flipped coins tend to come up the same way they started, and their abstract puts the chance of coming up as started at about .51 for natural flips. A 2023 experiment by Bartoš and colleagues, with 350,757 real flips, measured 50.8% with a 95% credible interval of 50.6% to 50.9%. This tool has no starting side, so it has no such tilt: heads and tails each get exactly one half.
The tally counts every flip in order, and the coins of a multi-coin flip count as that many flips one after another. The current streak is how many of the same side have come up in a row up to the latest flip. The longest streak is the longest so far, and the first one to reach a length keeps the record on a tie. Streaks are normal in a fair coin: any 5 chosen flips all land heads with chance 1 in 32, which is 3.125%.
With more than one coin you get the heads and tails counts, the percentages, the longest run in the batch and every coin in order as a line of H and T that you can copy. A single coin gets the flip animation. The side is chosen first and the spin only turns the coin to show it. If your device asks for reduced motion, the coin turns over at once with no spin.
Worked examples
Settle a decision with one coin
Press Flip. The coin spins and lands on heads or tails. To play first to two wins, flip until one side has two and use the tally as the score.
Flip 100 coins at once
Set the number of coins to 100. A fair coin gives exactly 50 heads only about 8% of the time (7.96%), and between 40 and 60 heads about 96.5% of the time (96.48%). So 46 or 57 heads is no sign of a bad coin.
Watch a streak form
Flip 20 or 30 times with one coin and watch the streak counter. Runs of three or four of the same side are ordinary in a fair coin. After a streak the next flip is still 50/50: the coin has no memory.
Ten coins: how often are exactly 5 heads?
Set the number of coins to 10 and flip many times. Exactly 5 heads happens in 252 of the 1,024 equally likely outcomes, which is 24.6%. It is the most common single result, yet it still happens only about one time in four.
How many heads fair coins give: exactly half is rare, but the count stays close to half
| Coins | Chance of exactly half heads | Likely range of heads | Chance of landing in that range |
|---|---|---|---|
| 10 | 24.6% (5 heads) | 3 to 7 | 89.06% |
| 100 | 7.96% (50 heads) | 40 to 60 | 96.48% |
| 1,000 | 2.52% (500 heads) | 469 to 531 | 95.37% |
Frequently asked questions
Is an online coin flip really 50/50?
Yes. Each flip is one fair draw of 0 or 1 from your browser's secure random number generator, so heads and tails each have a chance of exactly one half. There is no starting side, no spin and no throw to bias it.
Is a real coin toss 50/50?
Not quite. Diaconis, Holmes and Montgomery found that a coin flipped and caught by hand tends to land the way it started, about 51 times in 100. A 2023 study of 350,757 flips measured 50.8%. The bias is small, and it depends on how the person flips.
Why do I get streaks of heads or tails?
Random sequences contain streaks, and a sequence with none would be suspicious. The chance that 5 chosen flips all land the same chosen side is 1 in 32, so over many flips runs of 5 or more are expected to turn up.
If I get five heads in a row, is tails more likely next?
No. The chance that a run continues for one more toss is always 0.5 for a fair coin. Thinking tails is due is called the gambler's fallacy.
How many heads should I expect in 100 flips?
About 50, but not exactly. Exactly 50 heads happens about 8% of the time. Between 40 and 60 heads happens about 96.5% of the time. For 1,000 coins, 469 to 531 heads happens about 95.4% of the time.
Can I flip more than one coin at once?
Yes, up to 1,000. You get the heads and tails counts, the percentages, the longest run in the batch and the whole sequence of H and T to copy. The coins also count towards the running tally and streaks, in order.
Does the animation change the result?
No. The side is chosen before the coin starts to spin, and the animation only turns the coin so it lands showing that side. With reduced motion turned on in your device settings there is no spin at all.
Can I use a coin flip to decide a prize draw?
It is a fair flip, but this page keeps no proof that anyone else can check, and it is not an approved or audited draw. If the draw has rules, follow them, and flip in front of the people affected if they need to trust the result.
Sources & references
Updated Oct 15, 2026