Random Number Generator
Generate one or more random numbers in any range, using your browser's cryptographically secure random number source.
How the randomness works
Numbers are generated using the Web Crypto API's crypto.getRandomValues(), the same cryptographically secure randomness source used for encryption keys, with rejection sampling to avoid the small statistical bias that a naive Math.random() % range approach can introduce.
Common uses
- Picking a winner from a numbered list of entries
- Generating sample data for testing
- Settling a decision or assigning random order
Frequently asked questions
Is this fair for picking a raffle or contest winner?
Yes — it uses the Web Crypto API's cryptographically secure random source with rejection sampling to avoid statistical bias, so every number in your range has an equal chance of being picked.
What happens if I ask for more unique numbers than the range allows?
The tool shows an error rather than silently repeating numbers — for example, you can't get 20 unique numbers from a range of only 10.