Coin Flip

Flip a coin online

Press the refresh button for a fresh flip. Set How many coins above one and the tool flips that many independently and shows the whole sequence in order.

Everything happens in your browser. Nothing is uploaded, stored or logged, and no flip is written into the page address — a result restored from a link would not be a flip.

Where the randomness comes from

Each flip is a single draw from your browser’s cryptographically secure random number generator, the same facility that backs encryption keys. It produces one of exactly two outcomes, both equally likely.

That is a deliberately different design from the common approach of generating a decimal and asking whether it is above or below 0.5. Drawing one of two values directly leaves no rounding behavior to argue about and no edge case at the midpoint.

The gambler’s fallacy

Four heads in a row, and the next flip feels overdue for tails. It is not. The coin has no memory, the flips are independent, and the chance of tails is still exactly one half.

What confuses people is that the ratio really does settle toward even over many flips — so the intuition is picking up something real and drawing the wrong conclusion from it. The correction is dilution, not compensation. After 10 flips a 7–3 split is a 40-point gap in percentage terms; after 1,000 flips, seven extra heads is barely visible. The imbalance was never canceled out; it was swamped by everything that came after.

The raw difference between heads and tails can in fact keep growing as you flip more. It is the proportion that converges, and only the proportion.

Why 10 coins rarely gives 5 and 5

An even split is the single most likely outcome, and it is still uncommon — it happens under a quarter of the time across ten flips. There are simply more ways to arrange six heads and four tails, or four and six, than there are to arrange exactly five of each.

Flip a hundred coins here a few times and you will typically see something in the mid-forties to mid-fifties rather than a clean 50–50. That spread is the fairness, not a departure from it. A tool that produced exactly half heads every time would be doing something other than flipping coins.

How fair is a real coin?

Close to even, but not exactly. A tossed coin that is caught in the hand lands slightly more often on the face that started upward, because a real coin wobbles about its axis as well as spinning — so it spends marginally more time with its starting face up. Careful experiments put the effect at around 51 to 49 rather than anything a person could exploit casually.

Letting a coin land and bounce, or spinning it on a table instead of tossing it, introduces larger and less predictable effects: a spun coin can be noticeably biased by uneven wear on its faces. None of that applies here, because there is no physical object to be asymmetric.

Using a flip to decide

A coin flip is a good way to settle a choice you are genuinely indifferent about, and a surprisingly good way to discover that you are not. The useful part is often the moment after the coin lands, when you notice whether you are relieved or disappointed — which tells you what you actually wanted before the flip.

Frequently asked questions

Is this coin flip actually 50/50?

Yes. Each flip is a single draw from your browser's cryptographically secure random number generator, with exactly two equally likely outcomes — not a comparison against 0.5, which invites rounding arguments. Flip a hundred coins a few times and you will see the split hover near even without landing exactly on it.

After four heads, are tails more likely?

No. Each flip is independent, so the chance of tails is still exactly one half. The belief that a run must "even out" is the gambler's fallacy. What actually happens is that later flips dilute an early run rather than correcting it — the ratio drifts toward even while the raw difference can keep growing.

Why does flipping 10 coins rarely give exactly 5 and 5?

Because an exact split is only one of many possible outcomes. Across ten flips there are more ways to land on 6–4 or 4–6 combined than on 5–5, so the even split turns up under a quarter of the time. That is what fairness looks like in small samples.

Can I flip more than one coin at a time?

Up to 100. Each is flipped independently, and the tool shows every result in sequence so you can copy the complete run.

Is a real coin toss 50/50?

Very nearly, but not perfectly. A physical coin caught in the hand shows a small bias toward the side that started facing up, because coins wobble as well as spin. A coin allowed to land and bounce introduces other effects. This tool has no physical asymmetry to inherit.

Is anything stored or sent anywhere?

No. Flips happen in the page and are never uploaded, stored or logged — and they are deliberately kept out of the page address, since a flip restored from a link would not be a flip.