Math

Random Number Generator

What this does

Draw one to one hundred random integers within any range, optionally requiring unique picks, sorted for readability.

Enter your details

Runs in your browser

Calculator inputs

How to use it

Using the random number generator

  1. 01

    Set the range

    Minimum and maximum, both inclusive whole integers.

  2. 02

    Choose quantity and repeats

    One to one hundred numbers; uniqueness optional but common for raffles.

  3. 03

    Read your numbers

    Sorted in the “Your numbers” row; rerun for another draw whenever you like.

Good to know

Where random numbers earn their keep

Lottery lines, giveaway winners, sampling survey respondents, shuffling practice problems, picking who presents first; fair selection removes both bias and the appearance of it.

Unique versus independent

Lottery balls are drawn without replacement (unique mode); dice rolls repeat freely. Choosing the wrong style quietly changes your odds, so match the draw mechanics of whatever you are simulating.

A note on security

Math.random is fast and fine for games and demos but predictable to determined attackers. Passwords, tokens and cryptographic keys need dedicated CSPRNGs; never this tool.

How it's calculated

The math behind this calculator

Pick = min + floor(random() × (max − min + 1)) per draw

Each draw maps the platform’s uniform Math.random() onto your integer range. Unique mode keeps a set of already-drawn values and redraws collisions until the requested count is met; feasible only when the count fits inside the range, which is validated up front. Results arrive sorted ascending for easy checking.

Assumptions & limitations

  • Randomness comes from the platform’s Math.random; not cryptographically secure.
  • Both range endpoints are inclusive.
  • Unique draws require the range to contain at least as many integers as picks.

Worked example

Five unique lottery-style picks between 1 and 69; press calculate again for a fresh draw each time.

FAQ

Frequently asked questions

Can I get the same numbers twice?
Yes; every run is an independent draw; press calculate repeatedly until you like what you see.
Why did unique mode fail?
You asked for more unique numbers than the range contains integers; widen the range or lower the count.
Is this safe for passwords or keys?
No. Use a cryptographic random source for anything security-sensitive.
Are the endpoints included?
Yes; minimum and maximum can both appear among the results.

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