Random Number Generator

Generate random numbers.

Pick one or many random numbers in a range, with optional duplicate prevention.

How it works

Numbers are generated locally from a browser random source and formatted as a line-separated list.

Useful for lists, drawings, and quick picks.

Practical examples

  • Range 1–10 with count 10 and duplicates disabled returns every integer once, in random order unless sorting is enabled.
  • Range 1000–9999 with count 5 creates five quick sample IDs; leave duplicates enabled if repeated values are acceptable.
  • Range −5–5 works like a positive range and includes both endpoints.

How to read the result

  • Minimum and maximum are inclusive, and reversed inputs are automatically swapped.
  • Disabling duplicates rejects requests whose count is larger than the number of integers in the range.
  • The summary reports the smallest value, largest value, and sum of the generated list.

Limits and privacy notes

  • This is not a certified lottery drawing or cryptographic-key generator.
  • Very large unique requests become slower because each new value is checked against earlier results.
  • Numbers are generated locally in your browser and are neither uploaded nor saved.

Method used

  • When available, Web Crypto supplies an unsigned 32-bit value that is scaled to a number from 0 inclusive to 1 exclusive.
  • Each result uses floor(random × range size) + minimum, so both integer endpoints can be selected.
  • If Web Crypto is unavailable, the page falls back to Math.random and should not be used for security-sensitive work.
Sampling

With or without duplicates

  • Allow duplicates for independent draws.
  • Disable duplicates for unique picks.
  • Unique count cannot exceed the range size.
Review

Use the summary

  • Sorted output is easier to scan.
  • Min and max catch out-of-range expectations.
  • Sum helps with quick classroom or planning checks.
Randomness

Browser source

  • Browser crypto randomness is used when available.
  • This is not a certified lottery tool.
  • Generated lists are not stored.

Frequently asked questions

Are the minimum and maximum included?

Yes. Every integer from the lower endpoint through the upper endpoint can be selected.

Why was my unique-number request rejected?

With duplicates disabled, the requested count cannot be larger than the number of integers in the range.

Is the output suitable for passwords or cryptographic keys?

No. Use a dedicated security tool with unbiased key-generation rules for those tasks.

Does sorting change which numbers were picked?

No. Sorting only changes their display order after generation.

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