CalcArcade.

Random Number Generator

Set the smallest and largest number and how many you want. You get a list of random numbers with their sum, average, smallest and largest, and a seed that gives the same set again.

Your numbers

Result

How we calculate it

The numbers come from a pseudo-random generator (mulberry32). Each draw gives a number from 0 up to but not including 1, built from 53 random bits, and it is scaled to your range. For whole numbers the result is the smallest plus the draw times the number of values in the range, rounded down, so every value is equally likely. For decimals the choice is made among all the values with the places you chose. When you ask for unique numbers, a number is never used twice.

The seed is the starting value of the generator. The same seed with the same settings always gives the same numbers, and if you leave it empty a new seed is picked every time and shown as Seed used. Type that seed back in to get the same list again. With the seed 42 and the defaults the first number is 61.

Assumptions and limits

  • This is not suitable for passwords, keys or anything that must be unpredictable. The generator is meant for games, samples and teaching.
  • The numbers change whenever you change a setting. With a seed they only change when the seed or the settings change. To get a new set with an empty seed, change any value.
  • With unique numbers you cannot ask for more numbers than the range holds. The range is limited to −1,000,000,000 to 1,000,000,000 and 1000 numbers at a time.

Frequently asked questions

How do I pick a random number between 1 and 100?

Set the smallest number to 1, the largest to 100 and the count to 1, and leave the type on whole numbers. Both ends are included.

How do I get random numbers with no repeats?

Choose Yes for unique numbers. Each number is then drawn from those not yet used, so 1 to 10 with a count of 10 gives every number from 1 to 10 once in a random order.

What is a seed?

A seed is the number the generator starts from. Using the same seed gives the same list, which is useful when you want to repeat a draw or check someone else's.

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Worked example (a fixed example using the starting numbers, it does not change as you type)

Inputs: Smallest number = 1; Largest number = 100; How many numbers = 5; Type of number = Whole numbers; Unique numbers only = No, repeats are allowed; Order = As drawn; Seed = 42.

  • Numbers 61, 86, 18, 28, 87
  • Count 5
  • Sum 280
  • Average 56
  • Smallest 18
  • Largest 87
  • Seed used 42

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Last reviewed: . Formulas and assumptions are described on our methodology page. For information only; not professional advice.