Pick random whole numbers between a lowest and a highest number: one or many, with or without repeats, in the order drawn or sorted. Press New draw for a fresh set; the same seed always gives the same numbers.
The formula
One number
number = lowest + floor(r × range) where range = highest − lowest + 1 and r is between 0 and 1No repeats
draw by shuffling the range and taking the first numbers, or redraw any repeatThe generator is mulberry32, a small 32-bit pseudo-random generator, started from the seed. Numbers are whole and both ends are included, so 1 to 6 can give a 1 or a 6.
Worked example
Ten dice rolls (1 to 6, seed 7) sorted smallest first read 1, 1, 2, 3, 3, 4, 4, 5, 5, 6, and six different numbers from 1 to 50 (seed 2024) are 41, 36, 34, 2, 28, 35.
When to use it, and the mistakes to avoid
Use it for games and dice, picking a name or a winner, choosing a sample, or making up test data.
- Expecting variety from the same seed. The same seed always gives the same numbers: press New draw.
- Asking for too many different numbers. With no repeats, the count cannot be more than the range.
- Using it for passwords or security. It is pseudo-random and not secure.
- Reading a repeat as a fault. With repeats allowed, they are normal.
- Forgetting that both ends are included. 1 to 10 can give a 10.
FAQ
How does the random number generator work?
It starts a pseudo-random number generator from a seed, then turns each of its outputs into a whole number between your lowest and highest, both included. The same seed always gives the same numbers, which is why a shared link shows the same draw. Press New draw to put a fresh random seed in.
Are the numbers truly random?
They are pseudo-random: produced by a formula, but spread evenly and unpredictable enough for games, raffles, picking names and sampling. They are not suitable for passwords, security keys or anything where someone guessing the seed would matter. For those, use your device's secure random generator.
What does 'no repeats' do?
It makes every number different, like drawing from a hat. 6 numbers from 1 to 50 with no repeats can never show the same number twice. You cannot ask for more different numbers than the range holds: 11 different numbers from 1 to 10 is impossible, and the calculator says so.
Why do I get repeated numbers sometimes?
Because with repeats allowed, every number is drawn on its own, so a repeat is normal. Ten rolls of a die must show at least one number twice, since a die has only six faces. Random draws are usually less evenly spread than people expect. Turn on 'No repeats' if you need all different.
Can I use it to pick a lottery or raffle winner?
For a raffle or a classroom draw, yes: number the entries from 1, set the highest number to the count, ask for one winner and share the seed so others can check it. For a regulated lottery, no: official draws have their own rules and equipment, and this page cannot guess or improve your odds.