Dice Roller
Roll virtual dice — d4, d6, d8, d10, d12, d20, d100 — up to 20 at a time.
Written by Anil Gautam · Updated
What does dice notation like 3d6 mean?
NdS means N dice with S sides each, and the Roll button spells out what you are about to throw, such as Roll 2d6 for the default. Totals run from N up to N times S, and the average is N times (S + 1), divided by 2, so 2d6 averages 7, 3d6 averages 10.5 and the maximum pool of 20d6 averages 70. A d10 here runs from 1 to 10, and a d100 gives a single number from 1 to 100, which saves rolling two ten-sided dice for a percentile check.
Why does 7 come up most often with two dice?
Two six-sided dice have 36 equally likely combinations. Six of them add up to 7 (1 and 6, 2 and 5, 3 and 4, each in either order), so 7 turns up about 16.7 percent of the time, while 2 and 12 each need one exact pair and appear about 2.8 percent of the time. More dice pull the totals harder toward the average. With 3d6, a total of 10 or 11 comes up a quarter of the time, and each extreme, 3 or 18, appears about once in 216 rolls.
How do you roll with modifiers, advantage or drop-lowest?
The roller has no box for modifiers, so add them to the total yourself: 1d20 + 5 rolled as a 13 is 18. For advantage, set the count to 2, roll d20 and keep the higher die; for disadvantage, keep the lower one. The odds shift sharply: the chance of 15 or more on one d20 is 30 percent, rising to 51 percent with advantage and falling to 9 percent with disadvantage.
For ability scores rolled as 4d6 drop the lowest, roll four d6 and subtract the smallest die from the total shown: 6, 4, 3 and 1 give a total of 14, minus 1, for a score of 13. Mixed pools such as 1d8 + 1d6 need two separate rolls, because each roll uses one die type. The count box accepts 1 to 20 and pulls any larger number back to 20, and the total line appears only when you roll two or more dice. Below the result, the history lists your last 10 rolls with every die's value and the sum.
For a range that no die covers, such as 1 to 37, the Random Number Generator is the better fit, and the Coin Toss Generator handles simple two-way calls.