How to use the spin the wheel tool
Type your choices in the box, one per line, or pick a starter list. The wheel redraws as you type. Press Spin, click the wheel, or flick it and let go. It turns, slows, stops under the pointer, and the winner appears below.
Turn on "Remove winner after each spin" to draw several names in a row, such as first, second and third place. To make one choice more likely, open Weights and raise its number: weight 2 has twice the chance of weight 1. Typing a name twice does the same by giving it two slices.
How a spin is picked
The winner is chosen before the wheel moves. When you press Spin, the page asks your browser for a secure random number, the kind browsers provide for cryptography, and uses it to pick a choice. Only then does it work out how far to turn the wheel so the pointer ends up inside that slice. What you watch is a replay of a result that already exists, so a hard flick and a gentle one cannot change who wins. The flick only changes how long the show lasts.
The browser's generator is a pseudo-random one, built for security and seeded with enough unpredictable data. It is not a physical dice roll, but for picking dinner or a prize winner among friends there is no practical difference.
How a number becomes a slice
Each slice gets a share of the wheel equal to its weight divided by the total of all the weights.
chance of winning = weight ÷ total weight
Worked example. Pizza has weight 4, Tacos 2, Salad 1 and Soup 1. The total is 8. The page draws a whole number from 0 to 7. Numbers 0 to 3 mean Pizza, 4 and 5 mean Tacos, 6 means Salad and 7 means Soup. That gives Pizza 4 ÷ 8 = 50 percent and a 180° slice, Tacos 25 percent and 90°, and Salad and Soup 12.5 percent and 45° each.
A computer hands out random numbers in a fixed range, say 0 to 255. To pick one of 6 equal choices, you cannot just keep the remainder after dividing by 6, because 256 = 6 × 42 + 4. Four choices would get 43 chances and two would get 42.
| Method | Choices 1 to 4 | Choices 5 and 6 |
|---|---|---|
| Remainder only | 43 of 256 | 42 of 256 |
| Throw out 252 to 255, draw again | 42 of 252 | 42 of 252 |
The second row is called rejection sampling, and the wheel uses it, so every choice is exactly equal. The page draws from a much larger range, a 32-bit number, so the unevenness would be tiny anyway, but there is no reason to leave any in.
Is the wheel fair? The chi-square check
The Test the wheel tab spins 1,000, 10,000 or 100,000 times and counts the winners. For a fair wheel, the counts land near the expected numbers but almost never exactly on them. The chi-square statistic adds up the total gap:
Compare χ² with the critical value for (number of choices − 1) degrees of freedom. At the 5 percent level, the critical value is 3.841 for 2 choices, 7.815 for 4 choices, 14.067 for 8 choices and 18.307 for 11 choices. A result under the line looks like chance. A result over it happens about 1 time in 20 even with a fair wheel, so run it again before you worry.
Worked example. Six equal choices and 600 spins should give about 100 wins each. Say the counts are 96, 104, 99, 108, 93 and 100. Then χ² = (16 + 16 + 1 + 64 + 49 + 0) ÷ 100 = 1.46. The critical value for 5 degrees of freedom is 11.07, so this is an ordinary result.
Where the numbers come from
- Random numbers: the Web Cryptography API,
Crypto.getRandomValues(). It fills a typed array with cryptographically strong random values, and one call is limited to 65,536 bytes (MDN Web Docs). - Pseudo-random generators: NIST Special Publication 800-90A Revision 1 (June 2015), on how deterministic generators produce random bits from a seed.
- Chi-square critical values: the NIST/SEMATECH e-Handbook of Statistical Methods, table of critical values of the chi-square distribution.
No laboratory has tested or certified this wheel. Do not use it for gambling, lotteries or any drawing the law regulates. Raffle and sweepstakes rules differ by state and country.
What people use it for
Who goes first in a game, which student answers next, what is for dinner, which chore comes first, or who wins a small giveaway among friends. For a giveaway, record your screen with the full list showing, so everyone sees the list you used.
Tips and common mistakes
- To pick several winners, turn on Remove winner after each spin. Otherwise the same choice can win twice.
- To settle an argument, set Play to Best 2 of 3 (or 3 of 5, 4 of 7). The first choice to win the majority of spins wins the match. If the spins run out with a tie at the top, the tied choices go to sudden death: the next spin that lands on one of them decides it, and spins that land elsewhere do not count.
- The same choice twice in a row is normal. With 5 equal choices, a spin repeats the last winner 1 time in 5, and three in a row happens 1 time in 25.
- Twelve spins will look uneven. The Test tab shows the counts evening out as the spins pile up.
- Weights are whole numbers from 1 to 100. The wheel takes up to 100 choices of up to 60 characters, but 12 to 20 read best.
Questions
Can I make one choice more likely?
Yes. Open Weights and raise that choice's number. The chance of each choice is its weight divided by the total, and the slice grows to match.
Are my choices saved or sent anywhere?
Not unless you share. The list and the results stay in your browser. If you press Share on Facebook or Copy the link, the page sends the list, the weights and that result to AerialQuote so the link can show them; the link works for 90 days. The video is made in your browser and is not uploaded.
How do I post my spin on TikTok?
After a spin, press Share, then Make a video. The page replays your spin as a short vertical video with the clicks and the winner. On a phone, Share the video opens your share sheet, where you pick TikTok. If TikTok is not there, open the TikTok app and sign in once, or tap Save Video and then pick it from your photos with the + button in TikTok. On a computer, download it and upload it in TikTok.
Can I use it for a public giveaway?
It is fine for a casual draw among friends. If the law regulates your drawing, for example when tickets are sold or the prize is worth real money, check the rules where you live first.