Everyday Utilities

Random Number Generator

Three modes: a range of numbers, a unique lottery-style set with no duplicates, or decimals with adjustable precision. Everything runs in your browser, nothing is sent to a server.

This isn’t Math.random(). Every number here comes from your browser’s cryptographically secure RNG (crypto.getRandomValues), the same source used for encryption keys — and the range logic re-rolls any value that would introduce bias toward the low end of a range, a step most quick online generators skip entirely. Good enough for raffles, giveaways, and anything where fairness actually matters.

Pick one or several numbers within a range. Repeats are allowed within a single batch (like rolling a die more than once) — the toggle below only governs repeats across separate generations.

Click Generate to see your number(s).

Frequently asked questions

Is this “true” randomness or pseudo-random?

Cryptographically secure pseudo-random (CSPRNG) — not a physical entropy source like atmospheric noise. For virtually every practical use (raffles, games, sampling, testing) this is indistinguishable from true randomness and is what security software itself relies on; it’s a different thing from services that harvest physical noise, not a lesser one.

What is “modulo bias” and why does it matter?

A naive way to generate “a random number from 1 to 10” takes a random 32-bit number and uses the remainder after dividing by 10 — but 2³² doesn’t divide evenly by 10, so some remainders come up very slightly more often than others. This tool avoids that by discarding and re-rolling any value that would fall on the uneven part of the range, so every outcome has a truly equal chance.

Which mode should I use for a raffle or giveaway?

Unique Set — it draws distinct numbers with no duplicates in one batch, which is what you want when assigning entries or picking multiple non-repeating winners. Number Range allows repeats within a batch (like rolling a die more than once), which is the wrong tool for a raffle.

Does this generator remember or log the numbers it gives me?

No — everything runs client-side in your browser; nothing is sent to a server or stored anywhere.

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