Random Number Generator
Random numbers in any range.
Random Number Generator at a glance
Random Number Generator is a free online developer tool you can use right now to random numbers in any range โ no account, no install and no usage limit. It runs entirely inside your browser, so whatever you enter stays on your own device.
- Price
- Free โ no trial, no paid tier, no watermark
- Sign-up
- Not required
- Where it runs
- In your browser โ nothing is uploaded to a server
- Works on
- Chrome, Safari, Firefox and Edge โ desktop, tablet and phone
- Category
- Developer Tools
Set a range and generate.
About Random Number Generator
Pick a minimum and maximum and generate one number or many. Useful for draws, sampling, assigning turns, or seeding test data.
The range here is inclusive at both ends, which is worth stating because it is a genuine source of confusion. Asking for 1 to 10 can return both 1 and 10. Many programming functions are exclusive of the upper bound โ JavaScript's Math.random() scaled to 10 never returns 10 โ and the mismatch is a classic off-by-one bug.
For a draw or anything where a repeat would be unfair, use the unique option. Without it each number is drawn independently, so duplicates are not just possible but expected: drawing ten numbers from 1 to 10 independently will almost never produce all ten. That is correct behaviour for dice and wrong behaviour for a raffle, and the distinction catches people out.
On fairness: results come from your browser's random source, which is uniformly distributed โ every value in the range is equally likely. Human intuition disagrees with what that looks like. Genuine randomness produces clusters and short runs, and a sequence with no repeats at all would actually be evidence against randomness rather than for it.
How to use Random Number Generator
- Set the minimum and maximum for your range.
- Choose how many numbers you want, and whether they must be unique.
- Generate and copy the result.
Frequently asked questions
Are the minimum and maximum included?
Yes, the range is inclusive at both ends โ 1 to 10 can return 1 and can return 10. This differs from many programming functions, which exclude the upper bound.
Why did I get the same number twice?
Because each draw is independent by default, so duplicates are expected rather than surprising. For a raffle or any draw without replacement, switch on the unique option so each number appears at most once.
Is this random enough for a prize draw?
For an informal draw, yes โ it uses the browser's random source and is uniformly distributed. For anything with legal or financial consequences, use a process that can be independently audited, since no client-side generator can prove to a third party that a result was not re-rolled.
The results do not look random โ is something wrong?
Probably not. Genuine randomness produces clusters and short runs far more often than intuition suggests, and evenly spread results with no repeats would actually be suspicious. Small samples look lumpy; that is what random looks like.