Dice Roller

Choose how many dice to roll (1 to 10) and the sides per die: d4, d6, d8, d10, d12, d20 or d100. Every die in one roll has the same number of sides. Press Roll the dice and the result appears straight away, with no animation.

• With one die you see a single number.
• With several you see each die and the total, for example 4 + 2 + 6 = 12 for 3d6.
• A d10 shows 1 to 10, not 0 to 9. A d100 shows one number from 1 to 100.
• A count above 10 rolls 10 dice, and a blank or zero count rolls one. The page doesn't warn you, so glance at how many numbers came back.

Earlier rolls appear on the History line, newest first, up to 11 of them. They disappear when you reload the page.

For each die, the page draws a 32-bit number from your browser's cryptographic generator (crypto.getRandomValues), takes the remainder after dividing by the number of sides, and adds 1. Dice are rolled independently, so one die never influences another, and nothing carries over from the previous roll.

For a d4 and a d8, the 4,294,967,296 possible values divide evenly, so every face is exactly equally likely. For the other dice a few values are left over, which gives some faces one extra value. On a d6, faces 1 to 4 each come from 715,827,883 values and faces 5 and 6 from 715,827,882. That is a gap of about 0.00000002 percentage points, far too small to show up in any game you will ever play.

Two six-sided dice have 36 equally likely combinations, which is why the middle totals come up most:

A few more, all computed exactly:

• Any single face of a d20, including a 20, is a 5% chance.
• Roll 2d20 and keep the higher die, as some games ask: the chance of at least one 20 rises to 9.75%, and the chance of 15 or more rises from 30% to 51%.
• Rolling 4d6, at least one six turns up 51.77% of the time.
• With 3d6, a total of 10 or 11 comes up 25% of the time (54 of 216 combinations).

• Modifiers. For 1d20 + 5, roll a d20 and add the 5 yourself.
• Mixed dice. For 2d6 + 1d8, roll 2d6, then switch to d8 and roll one, and add the two totals.
• Drop the lowest. For 4d6 keeping the best three, roll 4d6 and subtract the smallest number shown from the total.
• More than 10 dice. Roll in batches, for example 10 and then 5, and add the totals.