Random Number Generator

Generate random integers, decimal numbers, bulk unique lists or dice rolls. Uses cryptographic randomness (window.crypto) for true randomness.

random-number.tool

Cryptographic vs Pseudo-random Numbers

Most random number generators use a mathematical algorithm seeded with the current time — these are pseudo-random. They are fine for games and simulations but predictable if you know the seed. This tool uses window.crypto.getRandomValues(), which draws entropy from your operating system's hardware randomness source. It is suitable for security-sensitive applications like generating tokens or selecting winners fairly.

Dice Mode

The dice roller simulates standard tabletop RPG dice: d4, d6, d8, d10, d12, d20 and d100 (percentile). Roll multiple dice simultaneously and see each individual result alongside the total — exactly as you would with physical dice.

Frequently Asked Questions

Yes — this tool uses window.crypto.getRandomValues(), the same API used for cryptographic key generation in browsers. It draws entropy from hardware sources (mouse movement, keyboard timing, CPU noise) via the operating system. It is not predictable from previous outputs the way a seeded pseudo-random generator would be.
Common uses: selecting contest winners fairly, assigning random IDs, creating test data, simulating dice for board games, generating lottery numbers, shuffling playlists, picking random items from a list, and statistical sampling. Cryptographic applications use random numbers for key generation and nonces.
In Bulk List mode, the unique option ensures no number appears twice in the output. It samples from the range without replacement — like drawing numbered cards from a deck without putting them back. If you ask for more unique numbers than exist in the range, the list stops at the maximum possible count.
A d20 is a 20-sided die, standard in tabletop RPGs like Dungeons and Dragons. The notation dN means a die with N sides. d6 is a standard six-sided die. d100 (or percentile die) generates results from 1 to 100, often used for percentage chance rolls.
Yes — use Bulk List mode with the range set to your lottery's number range, choose the count equal to how many numbers the lottery requires, and enable the unique option. For example, for a 6-from-49 lottery: min=1, max=49, count=6, unique=on.

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