GeneratorsFree
Free coin flip tool. Flip a virtual coin once or many times and see heads/tails counts.
Last updated 9 October 2026
This page does not use Math.random() if it can avoid it. It asks the browser for one cryptographically random byte through crypto.getRandomValues() and reads the lowest bit. Even, tails. Odd, heads.
That detail matters more than it sounds. Taking a remainder is the usual way to squeeze a random number into a small range, and it introduces a small bias whenever the range does not divide evenly into the source. Here the source is one byte, 256 values, and 256 divides by 2 exactly. There is no bias in this coin at all, not a small one. Every flip is 0.5, to the limit of the browser’s random generator.
If a browser somehow lacks crypto.getRandomValues, the page falls back to Math.random(). Every current browser has the first one, so in practice you are getting the good source. The fallback is fine for a coin and is explicitly not suitable for anything secret.
After nine heads in a row the next flip is 50/50. Not 51, not "due" for a tail. The coin cannot remember, and this page builds every flip from a fresh random byte with nothing carried between them.
What trips people up is that both of these are true at once. Ten heads in a row is unlikely before you start: 0.5 to the tenth power, which is 1 in 1,024. But once nine have landed, the tenth is an ordinary coin flip. The unlikely part already happened.
Runs are also far more common than people expect once you flip enough times. Flip 100 times and the chance of seeing five heads in a row somewhere is about 81%. Flip 1,000 times and the chance of seeing ten in a row somewhere is about 39%. Both are simulated estimates rather than exact figures. If a sequence from this page looks suspiciously streaky, that is what random actually looks like, and a sequence with no runs in it would be the strange one.
crypto.getRandomValues(). developer.mozilla.orgMath.random(). developer.mozilla.orgThe figures on this page were computed from this tool’s own code on 9 October 2026. Where a probability is marked as simulated, it came from 20,000 simulated runs and is an estimate, not an exact value.
It is the browser’s cryptographic random source, read one byte at a time. There is no seed, no cycle you could observe and no pattern carried from one flip to the next.
No. It is 50/50, exactly as the first flip was. Each flip is built from a fresh random byte and nothing is carried over. The belief that a result becomes "due" is the gambler’s fallacy, and it is the single most common mistake made with a tool like this.
Because that is normal. In 100 flips there is roughly an 81% chance of a run of five somewhere, and in 1,000 flips roughly a 39% chance of a run of ten. Those are simulated estimates. A sequence that alternates neatly would be the suspicious one.
No. The bias that affects most random-range code comes from taking a remainder, and appears when the range does not divide the source evenly. This page reads a single bit from a 256-value byte, and 256 divides by 2 exactly, so there is nothing left over to skew.
The count is capped at 1,000 and the cap is applied silently. Run it five times if you need more.
Only if nobody needs to verify it. The page keeps no record, produces no seed and gives you nothing to show afterwards. For anything with a prize or a dispute attached, use a method that leaves evidence.
Yes. Once the page has loaded, the flipping happens in your browser. Nothing is sent anywhere and nothing is stored.