Heads or tails?

How it works

Every number between your limits is equally likely, and each draw is independent of the one before. Your device's built-in secure random generator supplies the randomness, the same one used for encryption keys, so nobody can predict or steer the result.

Making the draw exactly fair takes care. Squeezing a large random value into a smaller range with a plain remainder favours the low numbers a little. This tool throws away the few values that would cause that, so a range of 1 to 6 gives each number exactly one chance in six (Lemire, ACM Transactions on Modeling and Computer Simulation, 2019).

Without repeats, the numbers are dealt like cards from a shuffled deck, using the Fisher–Yates shuffle (Knuth, The Art of Computer Programming, vol. 2): every possible ordered selection is equally likely. A coin flip is a draw between two values, so heads and tails each have a one in two chance.

The result is made in your browser and never sent anywhere. It is not part of the shared link, so a link repeats your settings, not your numbers.