At One Place

Dice roller

Roll any dice notation — 2d6, 4d6 drop lowest, d20 with advantage.

How it works

Rolls standard dice notation: 3d6 for three six-sided dice, 2d8+4 for a modifier, 4d6d1 to drop the lowest. Individual results are shown, not just the total.

The distribution is the part worth understanding. A single d20 is flat — every value equally likely. 3d6 is not: 10 and 11 come up about eight times as often as 3 or 18, because there are many ways to sum to the middle and only one way to reach either extreme. Systems that use multiple dice are choosing a bell curve deliberately.

Advantage and disadvantage roll twice and take the better or worse. Advantage is worth roughly +3.3 on average on a d20, but the effect is largest in the middle of the range and smallest at the extremes.

Every roll uses the browser’s cryptographic random number generator with rejection sampling, so there is no modulo bias — a naive implementation makes low faces very slightly more likely, which matters over thousands of rolls.

This tool runs entirely in your browser. Nothing you enter is sent to a server, logged or stored, and the page keeps working with the network disconnected.

Common questions

What does 4d6 drop lowest mean?
Roll four six-sided dice and discard the lowest, summing the remaining three. It is the common ability-score method and averages about 12.24 rather than 10.5.
How much is advantage worth?
About +3.3 on average on a d20, but the benefit is largest around the middle of the range and smallest at either extreme.
Why is 3d6 different from 1d18?
The sum of several dice clusters around the middle. On 3d6, a 10 is about eight times more likely than a 3.

Related pages

Sources

  1. Calculated on this page — At One Place

How these figures are compiled and checked