Random number generator
- 50 tools
- No watermark
- No daily limit
Pick numbers from any range, roll dice, flip a coin, or draw a set with no repeats. All of them are the same draw underneath, which matters more than it sounds: the mistake that makes a die favour low faces is subtle, invisible to anybody looking at the output, and is fixed here once rather than in four places. Every draw comes with a seed, so a number with anything riding on it can be checked afterwards.
Choose a range, or press one of the presets.
A seed makes a draw repeatable: put the same one back in with the same range and the same numbers come out. Announce it beforehand and anybody can check the result.
Frequently asked questions
Is it actually random?
When you leave the seed empty, the seed itself comes from the operating system's own random source, the one used to make encryption keys. `Math.random` is not used here at all: it is not built to be unpredictable, and it cannot be seeded, which would make the checking below impossible.
What does the bias you keep mentioning look like?
The usual way to squeeze a random value into a range is to take the remainder after dividing. When the range does not divide evenly into the generator's output, the lower numbers come up slightly more often than the higher ones. On a die that is completely invisible to anybody watching, and over a few thousand rolls it is unmistakable. This uses a rejection loop instead, and the distribution is tested: six thousand rolls, every face between nine hundred and eleven hundred.
Why would I want a seed on a random number?
Because sometimes something depends on the number. If you are picking a winner, assigning who goes first, or drawing an audit sample, the people affected have only your word for it. Announce a seed beforehand and anybody can put it back in afterwards and get the same numbers. Without a seed a draw is an assertion; with one it is a fact.
Is anything sent to a server?
No, and there is no server to send it to. The site’s security policy sets connect-src ‘none’, so the browser blocks network requests from these pages. Every number is generated in this tab.
What does the no repeats box do?
Drawing six numbers from 1 to 49 without any of them coming up twice, which is what a lottery slip or a raffle needs. Without it a number can appear more than once, which is what you want for dice and not for a draw.