Dice Roller

Roll one die or a handful, add a modifier, and keep a running history. Every face is drawn with the same rejection-sampling engine as the main generator, so a d20 here has no loaded side.

Fair dice, provably boring

A fair die gives every face the same probability: 1 in 6 on a d6, 1 in 20 on a d20. Software dice break that promise when a random byte is mapped onto the faces with a bare modulo — 256 is not divisible by 6 or 20, so a few faces pick up an extra share. This roller rejects the leftover values instead (for a d20, bytes 240–255 are redrawn), leaving exactly 12 complete sets of faces per byte. Before launch we rolled a d20 60,000 times through this engine: the most-rolled face and the least-rolled face differed from the expected 3,000 by at most 3.90% (counts ran from 2,883 to 3,087), which is normal sampling noise for that many rolls.

Dice notation like 2d6+3 means "roll two six-sided dice and add 3". The modifier here is flat — added once to the total, not to each die — the same convention tabletop games use.

FAQ

What is a d100?

A percentile die: a single roll from 1 to 100. Some games roll two ten-sided dice and read them as tens and units; the result is the same distribution.

Is the modifier added to every die?

No — once, to the total, matching standard tabletop notation such as 2d6+3.

How many dice can I roll at once?

Up to 50 per roll. The history keeps your most recent rolls on this page only; nothing is saved or sent anywhere.

Are these rolls as fair as physical dice?

Arguably fairer: physical dice have microscopic manufacturing flaws, while this engine's distribution is mathematically even by construction.