About this tool
The Random Number Generator produces truly random numbers within a range you choose, using your browser's cryptographic random source. Set the minimum, maximum and how many numbers you need, and optionally allow or forbid duplicates. It is perfect for raffles, games, sampling, giveaways and any decision that needs a fair random pick.
How to use
- 1Set the minimum and maximum.
- 2Choose how many numbers and duplicate rules.
- 3Generate and copy the results.
Benefits
- Cryptographically random.
- Unique or repeatable numbers.
- Generate many at once.
Run a fair draw with reproducible rules
A random result is only fair when the eligible range and duplicate policy are fixed before the draw. This tool uses the browser's cryptographic random source and rejection sampling to avoid the small distribution bias caused by simply applying a remainder to arbitrary random bytes. That makes it suitable for ordinary selections and games, but it does not create an auditable public lottery: the page does not publish a seed, preserve a signed draw record or verify who was eligible.
Practical uses
- Assign an unbiased starting order to a small group.
- Draw unique identifiers from a known range without replacement.
- Generate test values for interface checks where reproducibility is not required.
Checklist before relying on the result
- 1Publish the minimum, maximum and number of draws first.
- 2Decide whether duplicates are allowed before generating.
- 3Make sure the requested unique count does not exceed the range.
- 4Use a regulated or independently audited system for prizes, gambling or legal selections.
How secure browser randomness becomes a range value
The generator requests random bytes from the Web Crypto API, converts an accepted value into an integer inside the inclusive minimum-to-maximum range and repeats until the requested count is reached. When duplicates are disabled, selected values are tracked and cannot be drawn again. This is stronger than Math.random for ordinary browser use, although the page does not provide a reproducible seed or independent audit log.
Common mistakes to avoid
- Changing the rules after seeing an unwanted draw.
- Requesting more unique values than the range contains.
- Presenting a private browser draw as a regulated or independently witnessed lottery.
Frequently asked questions
Are the numbers truly random?+
They use crypto.getRandomValues, which is far more random than typical pseudo-random functions.
Can I get unique numbers only?+
Yes. Enable 'no duplicates' to draw each number at most once (within the range size).