Random Number Generator Wheel

A random number generator wheel you can watch

A button that prints a number asks you to take it on faith. A wheel shows you the whole set of possibilities and where the pointer landed, which is why classroom draws and giveaways use them. The result is identical; the credibility is not.

That matters most when someone else is watching. A number appearing in a box is an assertion. A wheel stopping on a slice is evidence, and everyone in the room saw the same thing at the same time.

Random number generator 1 to 10, 1 to 100, and every range in between

The quick-range buttons above the list load the ranges people ask for most: 1 to 2, 1 to 3, 1 to 4, 1 to 5, 1 to 6, 1 to 10, 1 to 20, 1 to 50 and 1 to 100. One tap replaces the list and redraws the wheel. The default is 1 to 10.

Any other range works the same way, because the wheel is just a list with one number per line. For a random number between 1 and 7, or 1 and 13, type those numbers in. For 1 to 1,000, paste the full list; the wheel accepts up to 1,000 entries.

Ranges that are not 1 to N are fine too. Even numbers only. Ticket numbers with a prefix, like A-101 to A-150. Prices like 5, 10, 20, 50. Past about 40 slices the labels stop being drawn because they would be illegible, but the slices and the draw are unaffected, and the result panel always shows the full winning entry.

Random number generator with no repeats

A raffle with three prizes needs three different numbers. Switch on “Remove the winner after each spin” and spin three times: each winner leaves the wheel, so the same ticket cannot win twice. The results list keeps the order they came out in, which is the order most draws need for first, second and third prize.

Leave the switch off when repeats are the point. Rolling a die twice is meant to be able to land on the same face, and a wheel used as a die should behave the same way.

How does a random number generator work?

Each spin asks your browser for a cryptographically secure random value, the same source used for encryption keys, and maps it onto the slices. The winning number is fixed before the wheel starts moving, and the animation is then calculated to stop on it.

Because the draw comes first, the number you get is the number your browser drew: nothing about the animation, the speed of your device or where a slice edge falls on screen can change it. After a spin, open “How this spin was drawn” under the result to see the 32-bit value the browser produced, whether any values were thrown away, and the arithmetic that turned it into your slice.

Is a random number generator truly random?

Not in the philosophical sense, and it does not need to be. A browser’s generator is seeded from unpredictable hardware events and is designed so that nobody can predict the next value from the last ones. For picking a number that is exactly what “random” has to mean.

The subtler risk is bias in how the random value becomes a slice. Plain remainder arithmetic gives the first few slices a slightly better chance whenever the slice count does not divide evenly into the generator’s range. This wheel uses rejection sampling instead, which throws those cases away and draws again, so every number has an identical chance. The draw was checked with a chi-square test over hundreds of thousands of spins, alongside a deliberately biased picker the same test is required to catch.

Compared with Google’s random number generator, dice and a hat

Google’s random number generator is convenient and invisible: nobody watching can tell whether it was clicked once or five times, and it cannot draw without repeats. Dice are fair and fast, but each one has a fixed number of faces, from 4 on a d4 to 20 on a d20, and only the people at the table see them. Numbers in a hat are transparent but slow to set up, and the person drawing can feel for a folded corner.

A wheel on a shared screen sits between them. Any range, one visible spin, no hands involved, and a result list everyone can scroll back through.

Where a number wheel fits, and where it does not

It fits small draws where being seen to be fair matters: a classroom picking who presents, a giveaway on a stream, a raffle at a club night, a family deciding who does the dishes by ticket number. It replaces a die when nobody has one, and it replaces “think of a number” when the person thinking of the number is also the person who benefits.

It does not fit anything that needs an audit trail. Nothing is recorded once the page closes, so a regulated lottery or a draw that could be disputed later should use a process that records the result. It also does not generate numbers in bulk. If you need 500 random numbers in a spreadsheet, a spreadsheet function will do that faster than 500 spins.

Quick recipes

Die: tap 1–6, leave the switch off, spin per roll. Two dice: spin twice and add. Coin with numbers: tap 1–2. Raffle: paste only the ticket numbers that were sold, switch on, one spin per prize. Classroom: number the class roster, paste the numbers, switch on, and nobody is picked twice until everyone has gone. Percentage roll: tap 1–100 and read the result as a percent. Weighted pick: repeat a number to give it a bigger slice, which everyone can see.