Random Number Generator — Cryptographically Secure, Free, No Upload

About Random Number Generator

The Random Number Generator produces batches of random numbers from a range you define, using your browser's cryptographically secure random source rather than the predictable Math.random(). You set a minimum and a maximum, choose how many numbers to generate (1 to 100), pick the number of decimal places (0 to 6), and optionally require that every value in the batch is unique. Click Generate and the results appear as a comma-separated list you can copy in one click.

Under the hood every draw reads fresh entropy from crypto.getRandomValues() into a 32-bit unsigned integer, the same CSPRNG browsers expose for generating cryptographic keys. For integers (zero decimals) the tool scales that value across the inclusive range min to max. For decimals it scales across the range and rounds to the requested number of places. When you ask for unique integers, the algorithm adapts to the range size: for ranges up to 10,000 possible values it builds the full pool and performs a cryptographic Fisher-Yates shuffle, then takes the first N, which guarantees no repeats; for larger ranges it draws values and rejects duplicates with a Set, capped at ten times the requested count to avoid an unbounded loop.

This is useful for sampling, picking lottery-style draws, seeding test fixtures with realistic spread, selecting raffle or giveaway winners, or generating dice-like rolls. Because the source is a CSPRNG, the output is suitable wherever you would distrust the bias and predictability of ordinary pseudo-random functions.

The tool validates your inputs and reports clear errors instead of producing nonsense. Min must be less than max, or you get a message saying so. Count must be between 1 and 100. If you request more unique integers than the range can hold (for example, 50 unique values from 1 to 10), it tells you the range is too small. Note that the unique guarantee applies cleanly to integers; with decimals enabled, uniqueness is not separately enforced, though collisions are extremely unlikely across a continuous range. All generation happens locally and nothing is sent to a server.