Random number generator
Fair random numbers in any range.
About this calculator
Set a range and how many numbers you want. Use it for raffles, picking a winner, games or sampling.
Turn on No repeats when each number should come up only once, as in a raffle draw.
How it works
Uses your browser's secure random source, with rejection sampling so that every number is equally likely.
The story behind it
Getting truly fair numbers has always been harder than it looks. In 1955, the RAND Corporation published A Million Random Digits with 100,000 Normal Deviates, an actual book of random numbers for scientists to look up. Today your browser has a secure random source built in. This generator uses it, with a technique called rejection sampling so that no number is more likely than another.
Why you can trust this calculator
- It runs in your browser. Nothing you type into it is sent anywhere.
- The method is explained on this page, so you can check it yourself.
- Free to use, with no sign-up.
- Results are estimates, so please double-check anything important.
- Spotted a mistake? Tell us and we'll look into it.
After 15 years as a mathematics educator, I built CalculStore to give students, teachers, professionals and anyone working with numbers simple, reliable tools.
Meet the founder