Click Flip for an animated coin toss. The outcome is decided by your browser's cryptographic RNG, so it's exactly 50/50 — no thumb-bias possible. Batch flip 10 or 100 to see the law of large numbers in action.
Physical coin flips have a small but measurable bias — about 51% in favour of the side that started face-up, due to wobble and tumble physics (Diaconis et al., 2007). For low-stakes decisions, that doesn't matter. For anything where fairness is contested, a digital flip with a CSPRNG removes any possibility of cheating.
This tool uses crypto.getRandomValues to draw a single bit and map it to heads or tails. The animation is decorative; the underlying RNG is the same as the password generator and dice roller on the rest of this network — uniformly random, unbiased, unpredictable. Nothing leaves your browser.
Yes — exactly. We map the lowest bit of a 32-bit cryptographic random integer to heads/tails. The bit is uniformly distributed by construction. Real coins have a tiny bias toward the starting face; the digital coin doesn't.
The mistaken belief that past flips affect future ones. After 5 heads in a row, the next flip is still 50/50, not 'due for tails'. Each flip is independent. The big-batch mode lets you see streaks of 5-7 happen naturally with no bias.
Because the result is decided cryptographically before the spin starts; the animation is just a visual effect. Designing the animation to actually settle on the chosen face would be more work for zero functional benefit.
No. There's no 'cheat' button, no settings to nudge probability. The only way to influence the outcome is to refuse to flip — which doesn't help anyone. If you suspect cheating from the other party, ask them to flip; the result is unbiased regardless of who clicks.
Yes — for any binary decision where both options are acceptable, a coin flip is the most rationally fair method. Cognitive science research suggests that the moment of the flip often reveals which outcome you actually wanted (you feel relief or disappointment). Use that information.
Where a coin flip beats arguing.
Two people, one parking spot, one slice of cake. Flip a coin instead of negotiating. Quick, fair, no bruised egos.
Football, rugby, tennis — the first move is decided by coin flip. The digital version works in any spectator-friendly setting (school PE, casual pickup games).
Stuck between two layouts and your team is split? Flip the coin. Whichever wins, ship it for a week and measure. Indecision costs more than a coin flip's worth of suboptimality.
Show students the law of large numbers — flip 100 times, observe convergence to 50/50, then 1000 times to see the curve smooth out. The batch mode handles the demo in two clicks.
Habits for getting value from a coin flip.
Decide BEFORE flipping that you'll honour the outcome. Flipping then refusing to accept defeats the purpose. The flip is a commitment device.
When the coin shows the side you secretly didn't want, your gut feeling is more honest than your stated indifference. Use that signal — it often clarifies the right answer.
Coin flips are for low-stakes ties. For 'should I take this job?' or 'should we have kids?' — actually deliberate. The coin can't model second-order consequences.
If both parties feel the stakes are real, agree on best-of-three or best-of-five. Statistically the same as a single flip but feels more 'earned'. The batch mode tracks results.