Online dice roller for D&D

What each die is for in D&D 5E

A standard D&D set has seven dice: d4, d6, d8, d10, d12, d20 and the percentile pair that makes a d100. The d20 decides whether you succeed; almost every other die measures how much: damage, healing, hit points or a result on a random table. These are their typical uses, each with a real example from the 5E SRD.

Hit dice follow the same ladder: a wizard rolls a d6 for each level, a fighter a d10 and a barbarian a d12, so the size of the die alone tells you how sturdy a class is. Damage dice work the same way for weapons, from the dagger's d4 to the greataxe's d12.

How to read dice notation

Dice notation packs a roll into a few characters. The number before the d is how many dice to roll, the number after it is how many sides each die has, and anything after a plus or minus sign is a flat modifier added once to the total. So 2d6+3 means roll two six-sided dice, add them, then add 3. A missing first number means one die: d20 is the same as 1d20.

Two suffixes cover rolls that keep only some of the dice: kh (keep highest) and kl (keep lowest). Advantage is 2d20kh1, two d20s keeping the higher; disadvantage is 2d20kl1; and the classic way to roll an ability score is 4d6kh3, four d6s keeping the best three. The table shows the range and the average result of each roll.

The formula box in the roller accepts the plain form: one kind of die and an optional modifier, such as 1d20+5, 8d6 or 1d8-1, with up to 20 dice of d4, d6, d8, d10, d12, d20 or d100. For a mixed roll, such as a rapier hit plus Sneak Attack (1d8+3 and 2d6), roll the two parts one after the other and add them; advantage, disadvantage and 4d6 drop lowest have their own buttons.

Advantage and disadvantage, in numbers

When a rule gives you advantage, you roll two d20s and use the higher; with disadvantage you use the lower. Advantage does not stack: two sources still mean two dice, and if you have both advantage and disadvantage they cancel out and you roll a single d20.

The odds change more than one extra die suggests. Against a target of 15, a straight d20 succeeds 30% of the time, advantage raises that to 51% and disadvantage drops it to 9%. The table shows the chance of rolling at least each number on the die itself, before modifiers.

Advantage helps most in the middle of the die. Needing an 11, your chance goes from 50% to 75%, the same as a +5 bonus would give. Needing a 20 it barely moves, and needing a 5 you were already likely to succeed. On average a straight d20 rolls 10.5, advantage 13.83 and disadvantage 7.18.

In the roller, the advantage and disadvantage buttons throw two d20s and strike out the die that does not count. Add your modifier to the total yourself, exactly as you would at the table.

Worked example: one attack, roll by roll

Here is a complete melee attack under the 5E SRD rules: a level 1 fighter with a longsword against a goblin. You can follow along with the roller above.

1. Work out the attack bonus. The fighter has Strength 16 (a +3 modifier) and a +2 proficiency bonus, so the attack roll is 1d20+5. The goblin's stat block gives it Armor Class 15 and 7 (2d6) hit points.
2. Find the roll you need. To hit AC 15 with +5, the d20 must show 10 or more: 55% of the time, or 79.75% with advantage. Under the rules for making an attack, a natural 20 always hits and a natural 1 always misses.
3. Roll to hit. The d20 shows 12, and 12 + 5 = 17, which meets or beats 15, so the attack hits.
4. Roll damage. A longsword deals 1d8 slashing damage plus the Strength modifier: 1d8+3. The d8 shows 6, for 9 damage. The goblin had 7 hit points, so it drops. On average this attack deals 7.5 damage when it hits.
5. Had the d20 shown a natural 20, it would be a critical hit: under Damage and Healing you roll the attack's damage dice twice and add the modifier once, so 2d8+3 instead of 1d8+3. That is 5 to 19 damage, 12 on average.
6. Had the goblin survived, it would strike back with its scimitar: +4 to hit against the fighter's chain mail, AC 16. It needs a 12 or more on the d20, a 45% chance, and a hit deals 1d6+2 slashing damage. That averages 5.5, which the stat block rounds down to 5.

Every step is one roll: 1d20+5 and 1d8+3 for the fighter, and 1d20+4 and 1d6+2 if the goblin gets its turn. Type each formula into the roller to play it out, or use the plain d20 button and add the bonus in your head.

Rolling ability scores with 4d6 drop lowest

The traditional way to roll a character's six ability scores is to roll four d6, drop the lowest die and add the other three, then repeat five more times and assign the totals as you like. The 4d6 drop lowest button in the roller does exactly that and strikes out the dropped die, so the whole table can see the roll was fair.

Rolling is generous on average but swingy. Across all 1,296 ways four d6s can land, the average score is 12.24, well above the 10.5 of a plain 3d6. An 18 comes up 1.62% of the time for each score, and 23.15% of scores are 15 or higher.

The alternative is the standard array, 15, 14, 13, 12, 10 and 8, assigned to the six abilities in any order, so every character starts on an equal footing. Many groups settle it in session zero: rolling makes memorable characters, while the array keeps the party balanced. Either way, agree before anyone rolls.

Rolling dice in a Nat20 session

This page is a solo roller: the rolls exist only in your browser tab, nobody else sees them and they are gone when you reload. When the whole table plays online, Nat20 throws the same 3D dice inside a shared session, with a few things a solo roller cannot do.

Shared rolls. Every roll in a session goes into a shared log with the roller's name, and anyone with the dice tray open watches other people's dice tumble and land on the real total. The log keeps the last 50 rolls, and the server checks that every total matches its dice before recording it.

Secret rolls for the DM. The DM can switch on secret rolls, which reach only the DM and never appear in the players' log: that is how you roll a hidden Perception check or a monster's saving throw without giving anything away. Advantage, disadvantage and keeping the highest or lowest die work the same way as here.

Check requests and initiative. The DM can ask chosen characters for an ability check: each player rolls the d20 on their own screen and Nat20 adds that character's modifier from their sheet, while the difficulty stays hidden unless the DM chooses to reveal it. In combat, players throw their d20 for initiative straight from the combat panel. For a single evening without accounts, the free initiative tracker keeps turn order in your browser.

Joining a session needs a free account, for the DM and for each player; there is no subscription. If you are still choosing where to play, see our comparison of free virtual tabletops.