To get unique, non-repeating numbers, enable the “unique numbers” option. The generator then performs sampling without replacement over your range using a partial Fisher–Yates shuffle, so each value appears at most once and every possible combination is equally likely. The only rule is that you cannot draw more unique numbers than the range contains — you can’t pick 10 unique numbers from 1 to 5, for example. Picking 6 unique numbers from 1 to 49 simulates a classic lottery draw.

The default mode draws from the Web Crypto API (crypto.getRandomValues) using rejection sampling to remove modulo bias, so every number in the range is exactly equally likely and the output is cryptographically unpredictable — excellent for fair everyday draws, raffles and giveaways. It is the browser’s CSPRNG rather than a certified true-random service seeded from physical noise such as atmospheric radio, so for regulated lotteries or gambling you should still use a certified source. AnyTool never uses the predictable Math.random for the crypto mode.

Seeded mode runs a deterministic Mulberry32 pseudo-random generator initialised from your seed text. Because it is fully determined by that seed, the same seed plus the same range, count and options always produce the identical sequence of numbers, which is ideal for unit tests, demos, procedural game content and sharing a result others can verify. This mode is reproducible but predictable, so it is not suitable for security-sensitive use — for that, keep the default crypto-secure mode.

AnyTool Random Number Generator runs entirely in your browser using JavaScript and the Web Crypto API. No range, option or generated number is sent to a server, saved, or tracked — close the tab and the numbers are gone. The page even works offline after the first load, so your randomness never leaves your device.