Random number generator
Pick a random number between any two numbers, or generate a whole list.
How to use the random number generator
- Enter the lowest and highest numbers you want (both are included).
- Choose how many numbers to generate, and whether repeats are allowed.
- Tap Generate. Copy the results with one click.
How the numbers are chosen
flipj uses your browser's built-in cryptographic random number generator (crypto.getRandomValues), the same source browsers use for encryption keys. We also avoid "modulo bias", a subtle flaw where some results come up slightly more often than others. Every result is generated on your device, so nothing you enter is sent to us.
With "no repeats" turned on, flipj shuffles the full range with the Fisher–Yates method and takes the first numbers, so every combination is equally likely, just like drawing numbered balls from a bag.
Uses
- Giveaways and raffles: number your entries, then pick the winner.
- Classrooms: pick a student by register number.
- Games: "guess the number" or choosing who goes first.
- Sampling: choose random rows from a list for a survey or audit.
Questions
Are the minimum and maximum included?
Yes. A range of 1 to 10 can produce both 1 and 10.
Can I generate numbers without repeats?
Yes. Turn off "Allow repeats" and each number appears at most once, as long as the range is big enough.
Can I use negative numbers or big numbers?
Yes, any whole numbers from about minus 9 quadrillion to plus 9 quadrillion.