Random Number Generator
Set a minimum and maximum and get random numbers in that range, one at a time or several at once, with or without repeats.
Numbers come from your browserโs cryptographic random source (crypto.getRandomValues). The last 50 draws are kept on this device only.
How to use the Random Number Generator
- Type your range into Minimum and Maximum. Left empty, they fall back to 1 and 100.
- Set How many for several numbers at once and tick No repeats if they must all differ. Numbers to leave out go in Exclude, separated by commas.
- Press Pick a number. The result appears in the large display and joins the numbered list below; Copy result copies every number from the last draw.
- Copy the settings link to send someone the same range and options.
Every number in the range is equally likely
Both the minimum and the maximum are included, and every whole number between them has the same chance. Set 1 to 45 and each of the 45 numbers comes up one time in 45; set 0 to 9 and each digit comes up one time in ten. Negative values work too, so a range like -10 to 10 behaves as written.
Draws are independent: by default nothing is removed from the pool, so the same number can come up again, and what appeared last time has no bearing on the next press. When you draw several numbers at once with No repeats ticked, none of them match. Numbers come from the browserโs cryptographic random source without bias. If the minimum is larger than the maximum, a short notice appears instead of a number.
How quickly repeats become likely
Repeats arrive sooner than most people expect. Over the default range of 1 to 100 it is already more likely than not that some number has appeared twice by the thirteenth draw, and a narrower range reaches that point faster still.
| Draws made | Chance of a repeat |
|---|---|
| 5 | about 10% |
| 10 | about 37% |
| 13 | about 56% |
| 20 | about 87% |
| 30 | about 99% |
Figures assume the default range of 1 to 100, drawn independently each time.
Frequently asked questions
Can I set my own minimum and maximum?
Yes. Type them into the Minimum and Maximum fields and both ends are included in the draw. Leave them empty and the generator falls back to 1 and 100.
Can I avoid repeats?
Yes. Set How many to two or more and tick No repeats, and the numbers in that draw never match. Anything listed under Exclude is left out too.
Does it handle zero and negative numbers?
Yes. Set the minimum to 0 or to a negative number and it is used as written, so a range such as -10 to 10 works.
Is it truly random?
Numbers come from your browserโs cryptographic random source (crypto.getRandomValues), with uneven leftovers discarded so every number in the range is equally likely. It is still not a certified draw for official lotteries.
What are the odds of one particular number?
One divided by the size of your range, on every press. Over 1 to 100 that is one percent, and it stays at one percent whatever came up before.
Is the history kept if I close the tab?
Yes. The last fifty draws are saved in this browser's local storage, so they survive a reload but never leave this device.
Can I pick several numbers at once?
Yes. Enter a count in How many, up to 1,000 per draw. Tick Sort ascending to list them from smallest to largest.