Is this coin flip truly random?
Yes — and in one specific way it is more random than flipping a real coin. Each flip draws a random byte from your browser's cryptographically secure random number generator (the same Web Crypto API used for encryption keys) and keeps its lowest bit. Of the 256 possible byte values, exactly 128 are even and 128 are odd, so heads and tails each have a mathematically exact 50% probability. There is no pattern, no memory of previous flips, and no way to predict the next result.
Real coins are (slightly) biased
Physical coin flips are not a perfect 50/50. Research by Persi Diaconis and colleagues predicted — and a 2023 study of over 350,000 recorded flips confirmed — that a caught coin lands on the same side it started on about 51% of the time, because of the slight wobble in a human toss. It is a small edge, but a real one: casinos would notice. A digital flip from a cryptographic generator has no starting side and no wobble, so it has no such bias.
Watching the law of large numbers
Flip a few times and the percentage split will look lopsided — 70/30 after ten flips is completely normal. Keep going and the split drifts toward 50/50: that is the law of large numbers in action. The session stats above make it visible. What it does not mean is that a streak is ever "due" to end — after five heads in a row, the next flip is still exactly 50/50. Believing otherwise is the gambler's fallacy.
Frequently asked questions
Is flipping a coin online really 50/50?
On this page, yes — exactly. Each flip takes one byte from the browser's cryptographically secure random number generator and uses its lowest bit. 128 of the 256 possible values give heads and 128 give tails, so the odds are precisely 50% with no bias and no pattern.
Is a physical coin flip truly random?
Almost, but not quite. Studies of hundreds of thousands of real flips show a caught coin lands on the side it started on roughly 51% of the time due to wobble in the toss. For everyday decisions the difference is negligible, but it is measurable — a digital flip avoids it entirely.
After several heads in a row, is tails due?
No. Every flip is independent — after five heads in a row, the next flip is still exactly 50/50. The feeling that tails is "owed" is the gambler's fallacy. Long streaks are rarer than short ones, but once a streak has happened, it has no influence on what comes next.
Are my flips saved anywhere?
No. The statistics live only in your browser tab for the current session — leave or refresh the page and they reset. Nothing is sent to a server or stored on your device.
Need more than two outcomes? The Dice Roller handles any number of dice with live probability distributions.