Dice Fairness

A fair die should have an equal likelihood of rolling each number. Only one number comes up on each roll, though, so how can you tell if your die is fair?



The most straightforward way to determine if a die is fair is to roll it many times and see if some numbers come up more often than others. But mathematically, streaks are expected in any series of random events, so how do you know if your die is unfair or if you're just lucky – "on a roll", as they say?

This app provides graphical and statistical tools to assess the fairness of any standard die (d4, d6, d8, d10, d12, d20). You can save multiple dice to compare them, and you can analyze both raw counts and cumulative probabilities. Fast, easy, free!