Heads or Tails

A fairer coin than a coin

A real coin flip is not quite 50/50. It lands very slightly more often on the face it started on, because it wobbles as much as it tumbles — an effect measured repeatedly in physics papers and, in 2023, in a study of 350,757 real flips.

This wheel has no such bias. Two slices, one draw from crypto.getRandomValues(), exactly 50% each. The result window shows the raw number and the arithmetic that turned it into a side.

It is a small thing, and for calling a coin toss between friends it does not matter at all. It is quite satisfying that the digital version is the more honest one.

What's on the Heads or Tails wheel

All 2 options are on the wheel to start with. Edit, delete or add to them — the wheel redraws as you type.

• Heads
• Tails

Streaks are supposed to happen

Six heads in a row feels broken. It is not — it happens about once every 64 attempts, so if you flip idly for a couple of minutes you should expect to see it.

The flips are independent: the wheel has no memory of the last result and no mechanism that could nudge the next one. A generator that avoided long runs would be less random, not more, because real randomness produces clusters.

This is worth remembering any time you look at a wheel result and think it looks suspicious. Runs are evidence of randomness, not evidence against it. There is a 10,000-draw simulation you can run yourself on how randomness works.