Plainwren

Wheel spinner and random name picker

Type one name or option per line and press Spin. Use it to pick who goes first, choose a student to answer, decide where to eat, or split people into an order. Your list is saved in this browser only.

How the winner is picked

The winner is chosen before the wheel moves, using your browser's cryptographically secure random number generator (crypto.getRandomValues). With n entries, each one has exactly the same chance, 1 in n. The pick uses "rejection sampling", which throws away the few random values that would make some entries slightly more likely than others.

The spin is just an animation: the wheel turns five full times and then stops on a random point inside the winner's slice, so what you see always matches the result. Speed, mouse position or how often you press Spin have no effect on who wins.

Worked example

With the six names above, each has a 1 in 6 chance (about 16.7%). If you tick "Remove the winner" and spin again, the next pick is from the five who are left, each with a 1 in 5 chance. Spin five times this way and you have put all six people in a fair random order.

If an entry appears twice in the list it gets two slices, so it is twice as likely to be picked. You can use this on purpose to give an option more weight.

Assumptions and limits

  • Up to 500 entries; each is cut to 80 characters. With many entries, the labels on the wheel get small, but the result text always shows the full name.
  • Your list is stored in your browser's local storage on this device, so it is there next time you open the page. It is never sent anywhere. "Clear saved list" deletes it.
  • This is a picker for everyday decisions, classrooms and games with friends. It is not meant for prize draws that have legal rules.

FAQ

Is it really random?

Yes. It uses the same secure random source browsers use for encryption keys, and the code is tested so that each entry wins equally often over tens of thousands of spins.

Can I share my wheel with someone else?

Copy the list from the box and send it; they can paste it into their own copy of the page. Nothing is stored on a server, so there is no share link.

Does it work on a projector or phone?

Yes. The wheel resizes to the screen. If your device is set to reduce motion, the wheel jumps straight to the result instead of spinning.