Coin Flip

How to use

1. Press Flip or click the coin. The coin spins and lands on Heads or Tails.
2. Need a series? Flip ×10 resolves ten flips in one press and adds all of them to the counters and the history.
3. Read the three counters underneath: heads so far, tails so far, and the longest streak — the longest run of the same side in this session, whichever side it was.
4. The strip at the bottom lists your last 60 results as H and T, newest on the right, so you can read a run at a glance.
5. Reset clears counters, streak and history and starts a fresh session. Nothing survives a page reload either.

Heads or tails: what to settle with a flip

A coin flip is the fastest way to end a two-option argument, and it works because both people accept the odds before the result. Typical uses in a gaming session:

• Who picks the map or the side in a casual scrim, when neither team wants to start the veto.
• Who goes first in a 1v1, a chess game, a board game or a Free Fire custom room.
• Which of two games you play tonight, when the lobby has been arguing for twenty minutes.
• Who buys the drop / who plays support — the small decisions that stall a five-stack.
• Best of three or best of five: flip until one side reaches two or three wins instead of a single toss.
• Tabletop and D&D: a coin is a clean d2 for a fifty-fifty in-world choice.

One honest limit: official esports matches decide sides in the game itself — CS2 plays a knife round, most titles run their own in-client toss — so treat a browser flip as the tool for casual and community play, not as something an admin will accept as a result.

Streaks: five heads in a row is normal

The complaint "this thing is broken, it gave me five heads in a row" is the most common thing said about any coin tool. Runs are not evidence of a broken coin; they are what fair coins do. The maths is exact, so here it is.

Read the last column again: in a hundred flips a run of six or more appears four times out of five, and the average longest streak is about seven. So if you press Flip ×10 ten times and the streak counter shows 7, the coin is behaving exactly as expected.

The flip side of the same fact is the gambler's fallacy. After four heads, tails is not "due" — the next flip is still 50/50, because the coin has no memory of the previous four. What does even out is the ratio: at 20 flips a 13–7 split is unremarkable, at 1000 flips you will usually sit within a couple of percent of half and half. The counts drift apart in absolute numbers while the percentage tightens.

How the flip is generated

Each flip asks the browser's crypto.getRandomValues() for fresh unpredictable bits — the same Web Crypto API that generates encryption keys — and maps them onto two outcomes. Because two divides 2^32 evenly, a coin needs no correction at all: every raw value maps cleanly onto heads or tails, and the rejection sampling the other randomizers on this site use for ranges like 1–6 or 1–100 never has to fire here. The result is a clean 50/50 with no seed and no repeating sequence.

The order matters too: the side is decided first, then the coin animates. The spin, the timing and how long you hold the button change nothing — there is no hidden physics simulation to game, and no way to "flip harder" for a better result.

A real coin is slightly messier. Minting is never perfectly symmetric, and the way a coin is tossed and caught can nudge the odds a little away from a perfect half. A software coin has no such physical quirks: the only thing behind it is a uniform draw of two equally likely outcomes.

Reading the counters like a stats page

The three numbers under the coin turn a toy into a small experiment, which is why teachers and streamers use it more than gamers do.

A quick classroom-style run: press Flip ×10 ten times to get 100 flips, then compare. Heads should land near 50 but rarely on exactly 50; the longest streak should usually be between 5 and 9. Both of those are far more convincing than being told that a coin is fair.

Three flips, eight options: using a coin for more than yes/no

One flip splits a question in two, but a short series splits it much further, because every extra flip doubles the number of outcomes: two flips give four, three give eight, four give sixteen. Flip three times, read the last three letters of the history strip left to right, and look the sequence up.

That covers a map pool of eight, a numbered list of eight challenges, or eight people deciding who goes first. If you only have five options, agree in advance that sequences 6, 7 and 8 mean "flip again" — which is exactly the rejection sampling the code uses internally to keep a range fair.

The same trick gives you odds smaller than a half. Two heads in a row is a 25% event, three in a row is 12.5%, four is 6.25% and five is 3.125%. So a house rule like "one time in eight, the loser picks the map" needs three flips, not a die.

And for splitting a group: flip once per person, heads goes to team A, tails to team B. Teams come out uneven fairly often, so decide beforehand what happens then — usually the last person flipped moves over to the smaller side.

What makes ours different

• Cryptographic randomness rather than Math.random(), with the reason spelled out above.
• Flip ×10 for series, so you can build a hundred flips in ten presses instead of a hundred.
• A longest-streak counter and a 60-result history — most coin pages show one result and forget it.
• The whole coin is clickable, which makes it usable one-handed on a phone during a match.
• No sign-up, no ads over the coin, no waiting for an animation you cannot skip.

What it does not do: it does not save your session anywhere, does not support weighted or three-sided coins, and does not claim any kind of external certification of fairness. The fairness argument here is the code path described above, not a badge.

Privacy

The flip happens entirely inside your browser. Nothing is sent to a server, there is no account, and no log of your results exists anywhere — so no one can look up what you flipped or change it after the fact. Reset clears the counters instantly, and closing the tab does the same.

FAQ