RunTheTests

Random Number Generator

Generate random numbers in a range, without modulo bias.

System verdict

RESULT

71

Generated with crypto.getRandomValues using rejection sampling, so every value in range is equally likely — no modulo bias toward the lower numbers.

Diagnostic telemetry
Number
71
Range
1 to 100 inclusive

What this cannot tell you

  • Uses the browser’s cryptographic randomness (crypto.getRandomValues). Suitable for general use; for security tokens use the dedicated password tools.
  • Bounds are inclusive.

How this calculation works

Numbers are drawn with crypto.getRandomValues and rejection sampling, so every value in the range is equally likely — a naive modulo would subtly favour the smaller numbers.

What the results mean

No modulo bias
Taking a raw random value modulo the range size skews toward lower numbers when the range does not divide evenly. Rejection sampling avoids that.

Frequently asked questions

Is this random enough for a lottery or draw?

For a casual draw, yes — it uses the browser’s cryptographic randomness, which is far better than Math.random. For anything with money or legal weight at stake, use a purpose-built, auditable system rather than a web page.

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