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Random Integer Range Generator

Draw one number or thousands from any range, with an option to forbid repeats. Asking for more unique numbers than the range contains is reported rather than looping forever. Values come from the browser cryptographic random number generator using rejection sampling, so every number in the range is exactly as likely as every other — which matters when the draw decides something. Everything is generated in your browser; nothing is uploaded and no result is recorded anywhere.

How it works

Draws whole numbers from a range you set, optionally without repeats. Asking for more unique numbers than the range contains is reported rather than looping forever.

Numbers come from the cryptographic random number generator, so they are suitable for drawing lots or picking a winner as well as for filling test data.

Values are generated in your browser and never sent anywhere.

Generated numbers

Adjust the settings above and values appear here.

Frequently asked questions

Is every number in the range equally likely?

Yes. The generator draws from a cryptographic source and rejects the values that would make the mapping uneven, rather than taking a remainder — which would make the low end of the range fractionally more common.

What happens if I ask for more unique numbers than the range holds?

It is reported as an error rather than attempted, because it is impossible: drawing eleven unique numbers from a range of ten cannot succeed, and a naive implementation would loop forever trying.

Can I use this for a prize draw?

The randomness is sound enough for that. If you are drawing from a list of names rather than numbers, the name picker does it directly and shows the result more clearly.

Are negative numbers supported?

Yes — the range can start below zero, and the bounds can be given in either order.

Why did I get the same number twice?

Unless "no repeats" is on, each draw is independent, so repeats are expected — with a range of ten and ten draws, seeing a repeat is more likely than not. That is what independence means, not a fault in the generator.

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