Random Number Generator — Crypto Strong

When you need a random number generator

Random numbers underpin everything from password generation to lottery draws, game design to scientific simulations. This tool gives you cryptographically secure random integers in any range — suitable for raffles, prize draws, randomised testing, sampling, or just picking a number between 1 and 10.

Math.random vs. crypto.getRandomValues

JavaScript's Math.random() is a pseudo-random generator suitable for non-security uses but has detectable patterns that make it inappropriate for anything where randomness matters cryptographically. This tool uses window.crypto.getRandomValues() instead — the same source used by password generators, UUID generators and cryptographic libraries.

No-repeat mode

For raffles, lottery draws, or any case where you need unique winners, tick "No repeats". The tool generates numbers without replacement — once drawn, a number isn't drawn again. The count can't exceed the range size in this mode (you can't draw 100 unique numbers from 1 to 50).

Common uses

• Raffle and prize draws (transparent, reproducible-ish if you screen-share the result).
• Randomly picking a team from a list (assign each member a number).
• Generating test data for software.
• Statistical sampling — selecting random records from a dataset.
• Picking a number for a game (1-d20 dice roll = min 1 max 20).
• Random ordering — generate a random number per item then sort by it.

Tips

• For fair raffles, screen-share the page during the draw and announce the inputs (min, max, count).
• For reproducible "random" sequences (testing), use a seeded PRNG instead. This tool is unseeded.
• For very large ranges (more than 2^53), this tool can't represent the values exactly — use BigInt-aware tools.

FAQs

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