ToolBirch

Random Number Generator

Cryptographically secure integers in any range, unique if needed.Generators

Random Number Generator

Cryptographically secure integers in a range you define, with an optional unique mode.

About this tool

Most online randomisers use Math.random, which is fine for games and wrong for anything that matters. This generator draws from crypto.getRandomValues with rejection sampling, so every value in your range is equally likely — and unique mode guarantees no repeats.

How to use the Random Number Generator tool

  1. Set the range and count. Any integer range, drawing 1–1000 values.
  2. Enable unique mode (optional). Guarantees no value repeats; impossible requests are explained.
  3. Generate and copy. Results appear as a copyable list.

Supported formats

Input

  • Minimum and maximum integers
  • A count between 1 and 1000

Output

  • A list of random integers

Inputs are validated before anything is processed. Invalid values and unsupported files are rejected with a clear error instead of failing silently.

Frequently asked questions

Are draws uniform?

Yes. Rejection sampling removes the modulo bias that plagues naive modulo approaches.

What does unique mode guarantee?

Exactly the requested count of distinct values, provided the range is large enough — the tool says how many exist otherwise.

Can I use this for giveaways?

Yes; the crypto-grade draw is as fair as a local machine can be. Record a hash of the output if you need provability.

Are decimals possible?

No. This tool draws integers; for decimals use a scripting environment.

Privacy

Everything you enter stays in this browser tab. There is no upload endpoint for tool inputs, no account, and no server-side copy of your text or files. Results are produced locally and disappear when you close the page.

No account is required and no file is ever uploaded. See the privacy policy for details about analytics and the limited data this site stores.

Known limitations

  • Integers only; no float mode.
  • Unique mode caps out when the range is smaller than the count.
  • Results are not committed or auditable beyond copying them.

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