Is a Spin Wheel Really Random? How NameWheels Picks a Fair Winner

"Is this thing rigged?" is the first question a class, a stream chat or a group of friends asks when the same name comes up twice. It's a fair question. A spinning wheel looks random, but whether it actually is depends entirely on how the software decides where the wheel stops. This article explains, in plain language, how NameWheels picks a result, why repeats happen even on a perfectly fair wheel, and how you can check fairness yourself.

The short answer

Yes. On NameWheels every entry on the wheel has exactly the same chance of being picked on every spin: with 20 names, each one has a 1 in 20 (5%) chance. The winner does not depend on where a name sits on the wheel, how long the wheel spins, or what was picked last time.

How NameWheels picks a winner

1. The winner is chosen first. When you press Spin, the page asks your browser's cryptographic random number generator (crypto.getRandomValues, the same source browsers use for security purposes) for a random number, and turns it into a whole number between 1 and the number of entries.
2. No "modulo bias". Converting a large random number into a small range can slightly favour some results if done carelessly. NameWheels uses rejection sampling: the rare random values that would cause that bias are thrown away and redrawn, so each entry's chance is exactly equal.
3. The animation follows the result. The page then calculates a landing point at a random spot inside the winning segment and animates the wheel to it, with a few full turns for suspense. The spin is just the presentation; it can't change the outcome.
4. Everything happens in your browser. No server is involved in choosing the winner, and nobody (including us) can steer the result.

Why the same name can come up twice

A fair wheel has no memory. Each spin is independent, so the name that just won has the same chance as everyone else on the next spin. Repeats feel suspicious, but they're expected:

• With 25 names and 10 spins, the chance that at least one name is picked twice is about 88%.
• With 30 names and just 5 spins, it's still about 30%.

This is the same maths as the famous "birthday problem": it takes surprisingly few draws before some repeat becomes likely. And from any one person's point of view, being picked at least once in 10 spins from 25 names happens about 34% of the time—so plenty of people will also go several spins without being chosen.

If you don't want repeats: remove the winner

When fairness means "everyone gets exactly one turn"—cold-calling in class, presentation order, a raffle with several prizes—you want sampling without replacement. On NameWheels:

1. Spin the wheel.
2. In the winner pop-up, click Remove & Spin. The winner is taken off the wheel and the wheel spins again for the remaining names.
3. When the round is over, click Restore removed under the name list to put everyone back for the next round.

Each spin is still uniformly random among the names that are left, so the final order is a fair random ordering of the whole list.

Giving some entries extra chances

Sometimes you want unequal odds—say, raffle tickets where one person bought three. NameWheels has no hidden weighting, so the transparent way to do this is to add that name three times. Each copy has the same chance as any other entry, so a name listed 3 times on a 30-entry wheel has a 3 in 30 (10%) chance.

How to check fairness yourself

You don't have to take our word for it. A simple test:

1. Put a small list on the wheel, for example A, B, C, D.
2. Set Spin length to Short and turn the sound off.
3. Spin 100 times and tally the results.

Each letter should come up roughly 25 times. Don't expect exactly 25—random results wobble. With 100 spins, counts anywhere between about 16 and 34 for a letter are well within normal variation. If one letter came up 60 times, something would be wrong. The more spins you do, the closer each share gets to 25%.

Showing fairness to an audience

• Show the list before you spin. On stream or in class, let people see every entry on the wheel.
• Share the wheel. The Share button creates a link containing the exact list, so anyone can open the same wheel.
• Decide the rules first. Announce before spinning whether winners are removed and what happens if someone isn't present.
• Record it. For giveaways, a recording or VOD of the live spin is the best proof that the draw happened as shown.

The bottom line

A wheel is only as fair as the code behind it. NameWheels decides the result with an unbiased, cryptographically strong random number and gives every entry an equal chance, then animates to that result. Repeats are normal; when you need everyone to get a turn, use Remove & Spin.