Free tool
Random Number Generator
Pick a number between any two values, or draw a whole set at once. Optional unique results for raffles, teams and orderings.
Set a range, then generate
Pick a number between 1 and 100
That is the default above, because it is by far the most common thing people want: a single number in a familiar range, used to settle a guessing game or to pick from a numbered list. Change the two boxes and the same mechanism covers a lottery-style draw, a random page of a book, or a number between minus fifty and fifty.
Each draw is independent and every number in the range has the same chance. If you generate five numbers between 1 and 10 with unique results switched off, seeing the same number twice is not a fault; with only ten possibilities and five draws, a repeat is more likely than not. That is the birthday problem in miniature, and it catches people out constantly.
When to switch on unique results
Unique results turn the generator from a series of independent draws into a draw without replacement, which is the difference between rolling a die repeatedly and pulling names out of a hat. Use it whenever the same result appearing twice would be wrong: allocating twelve people to twelve slots, picking six raffle tickets from two hundred, or shuffling a numbered running order.
Leave it off when each draw genuinely stands alone. Simulating dice, sampling with replacement for a statistics exercise, or generating a string of numbers where repeats are meaningful all need independent draws.
What "random" means here, and where it stops
The numbers come from your browser’s built-in generator, which is a pseudo-random algorithm: a deterministic sequence that passes statistical tests for randomness but is ultimately produced by a formula from a starting seed. For choosing who does the washing up, that distinction has no practical consequence. The output is uniform, unpredictable in any way you could exploit, and unbiased across the range.
It becomes a real limitation in two situations. Anything where money or a legal obligation rides on the result needs certified randomness and an audit trail, which this page deliberately does not provide, since it stores nothing. And anything cryptographic needs a generator designed for that purpose. For a fuller account of the difference, see are online random generators actually random?