Random Number Generator

The Random Number Generator produces one or many random integers within any range you choose, with two extra controls most simple generators skip: a "no repeats" mode that draws numbers without replacement, and a cryptographically secure mode that pulls from the Web Crypto API's random number source instead of `Math.random()`. Set a minimum, maximum and how many numbers you want, toggle the options that matter, and click Generate — the result appears instantly with a one-click copy button. Whether you need a random number picker for a quick decision, want to generate random numbers in bulk for test data, or are looking for a true random number source you can trust, this covers all three cases in one tool.

The distinction between the two modes matters for different use cases. `Math.random()` is fast and statistically fine for games, raffles, sampling and everyday randomness, but it isn't specified to be cryptographically unpredictable — a determined attacker could theoretically model or predict its output in some JavaScript engines. The "cryptographically secure" mode instead uses `crypto.getRandomValues()`, the same underlying source browsers use for generating encryption keys, with rejection sampling applied so the result stays perfectly uniform across your chosen range (avoiding the subtle bias a naive modulo operation would introduce).

"No repeats" mode is a genuinely different algorithm, not just a filter: it performs a partial Fisher-Yates shuffle over every possible value in your range and takes the first N, which guarantees no duplicates and keeps every possible number equally likely to appear (unlike naively re-rolling on collision, which subtly skews probabilities). This is exactly what you want for raffle drawings, choosing multiple unique winners, or dealing out unique reference numbers — set min/max to your range, count to how many you need, and no repeats on.

Common uses span lottery number generation, picking a random participant identifier, generating test data, settling a decision with an unbiased number, and classroom or game-night activities. Every number is generated locally in your browser — nothing about your range, count or the results themselves is ever sent anywhere.