Decision Wheel Spinner

What is a decision wheel?

A wheel you fill with your own options and spin to pick one of them at random. It settles the questions that are too small to be worth arguing over and too annoying to leave open: who presents first, where lunch is from, which of the three ideas gets built.

The draw happens in your browser. Nothing you type is uploaded, so real names and real projects are fine to put on it. There is no account and nothing to install.

How to use it

1. Type your options into the box, one per line, between 2 and 100 of them
2. The wheel redraws as you type, so you can see the segments before committing
3. Press Spin the wheel
4. To build an order rather than pick one thing, pressSpin again without the winner and keep going

How is the winner chosen?

The winner is drawn first and the animation is fitted to it. The moment you press the button, the browser's random number generator picks one segment, and the stopping angle is then worked backwards so that segment lands under the pointer. The spin you watch is a rendering of a decision that has already been made.

This matters because it rules out the thing people suspect about physical wheels: there is no momentum, no weighting of the disc, no skill in the flick. Every option listed once has exactly the same chance — 25% with four options, about 16.7% with six.

How do I weight one option?

Enter it more than once. Each line is its own segment, so an option on two of four lines takes up half the wheel. Same four lines, different breakdown:

How do I pick a whole order instead of one winner?

After a result, press Spin again without the winner. That option is removed from the list and the wheel spins on what is left, so nobody can be drawn twice. With 4 names you press it 3 times and end up with a complete running order.

This is the difference between a wheel and a dice roll, and it is usually what people actually want. Drawing a presentation order by spinning the same wheel four times gives you repeats; removing each winner gives you a permutation.

Is the browser's random number generator fair?

Fair enough for deciding lunch, and not fair enough for anything with money on it. The generator behind Math.random() is a pseudo-random one: Chrome, Safari and Firefox all use xorshift128+, which produces sequences with no bias any person could detect or exploit in normal use.

What it is not is cryptographically secure. The internal state can in principle be recovered from enough observed output, which means you should not use this wheel — or any wheel in a web page — to award prizes of real value, allocate money, or run anything a participant has a motive to game. For those, draw in front of everyone with a method nobody controls.

Will repeated spins even out?

Slowly, and much more slowly than people expect. With four options each at 25%, the spread you should expect after 20 spins is about 10 percentage points, so seeing one option come up 8 times out of 20 instead of 5 is ordinary. After 500 spins that spread narrows to roughly 1.9 points.

Short runs look lumpy for the same reason. One option failing to appear at all across 10 spins happens 5.6% of the time, and the same option winning three times in a row happens 1.6% of the time — about one run in 64. A streak is evidence of nothing. If it bothers the group, remove each winner instead.

When should you not let the wheel decide?

When the options are not actually equivalent. A wheel is a good way to break a tie between choices you would be content with either way, and a bad way to avoid a decision you have the information to make. If you find yourself hoping for a particular segment as it slows down, that is the answer — close the tab and go with it.

It is also the wrong tool where the outcome has to be auditable: legal draws, prize allocation, or anything a participant might later dispute. Nothing here is recorded, so there is no trail to show afterwards.

Notes

• Between 2 and 100 options. Duplicate lines are allowed and act as weights
• Long labels are shortened on the wheel face; the full text is shown in the result
• Labels are hidden above 40 options, where the segments are too narrow to read
• If your system is set to reduce motion, the wheel jumps straight to the result instead of animating
• Options and results stay in your browser and are never sent to a server