Dice are written in standard dice notation: NdX+M, where N is how many dice you roll, X is the number of sides, and M is a flat modifier. 2d6+3 means "roll two six-sided dice and add 3." A negative modifier such as 1d20-1 subtracts instead. Type it straight into the roller, and mix dice in one roll: 1d20+1d4+5 is an attack with Bless, 1d8+2d6+3 is a rogue's rapier with Sneak Attack.
Add keep and drop to the end of a group: kh keeps the highest dice, kl keeps the lowest, dl drops the lowest and dh drops the highest. So 2d20kh1 is advantage, 2d20kl1 is disadvantage and 4d6dl1 is the classic ability-score roll. d% is shorthand for a d100.
The d20 drives the three core rolls in 5e — attack rolls, ability checks, and saving throws. When you have advantage, roll two d20s and keep the higher result; with disadvantage, keep the lower. Advantage is worth roughly +3 to +5 on average, and it helps most when your target number is around the middle of the die.
The smaller dice (d4–d12) handle weapon damage and healing, while the d100 (percentile) is for random tables. To roll ability scores, use the 4d6 drop lowest preset: it rolls four d6, discards the lowest die, and sums the rest — averaging about 12.2 per score instead of the 10.5 you get from rolling 3d6.
Roll a d4, d6, d8, d10, d12, d20 or d100
Tap any die at the top of the page to roll it once, or type the roll you need: 1d4 for a dagger, 1d12 for a greataxe, 8d6 for a fireball. Tap the small + on a die to stack dice into one roll, like 1d8+2d6 for a rapier with Sneak Attack. Every roll lists each die, so you can check a crit or a reroll at a glance.
Advantage and disadvantage odds
Enter the DC or AC you need in the Chance to hit box and the roller works out your odds, including with advantage and disadvantage. The swing is biggest in the middle of the die: needing 11 or higher on the d20 is 50% normally, 75% with advantage and 25% with disadvantage. Needing 15 or higher is 30% normally, 51% with advantage and only 9% with disadvantage. On attack rolls a natural 20 always hits and a natural 1 always misses, whatever the total.
Rolling ability scores
Tap Roll all 6 ability scores to roll 4d6dl1 six times. Each score averages about 12.24, so a rolled set totals about 73.5 on average, a little above the 72 of the standard array (15, 14, 13, 12, 10, 8) — but any one set can land well above or below it. If your table wants even characters, use the point buy calculator instead.