Dungeons & Dragons uses seven dice – d4, d6, d8, d10 (two of them for percentiles), d12 and d20 – and a compact notation to describe how to roll them. “2d6+3” means roll two six-sided dice and add 3; “8d6” is a fireball; “1d20+7” is an attack with a +7 bonus. Character creation often uses “4d6 drop lowest”, written 4d6kh3: roll four d6s and keep the highest three.
This roller reads that notation directly. Type one or more expressions separated by commas – a whole turn’s attack and damage, or six ability scores – and it rolls them all, showing the individual dice, the dice kept, each result, the exact average and the possible range. Supported forms include NdS, d% for a percentile die, plus and minus modifiers, combinations of dice such as 1d8+1d6+2, and keep or drop rules: kh (keep highest), kl (keep lowest) and d (drop lowest).
The chart shows the exact probability distribution of the first expression with your result highlighted, and the tool reports the chance of rolling your result or higher – handy for knowing just how lucky that 18 on 4d6kh3 was (about 1.6%).
How to use the DnD Dice Roller
- Roll
- Dice expression(s), separated by commas
Everything is calculated in your browser, so results appear instantly and nothing you type is sent to a server.
How it works
Each expression is parsed into dice groups and constants. Dice are rolled with the secure random generator; keep and drop rules sort the group and keep the requested dice. The exact distribution is built by enumerating keep-rule groups and convolving all the parts, which gives the exact average and the chart.
Worked example
Rolling “1d20+5, 2d6+3”: the attack came up 13 + 5 = 18 and the damage 4 + 6 + 3 = 13. The attack averages 15.5 (range 6–25) and the damage averages 10 (range 5–15). For 4d6kh3 the exact average is 15,869/1,296 ≈ 12.24, noticeably higher than the 10.5 of plain 3d6.
Supported notation
| You type | Meaning |
|---|---|
| d20 or 1d20 | one twenty-sided die |
| 3d8+2 | three d8 plus 2 |
| 1d8+1d6+3 | mixed dice plus a modifier |
| d% | a percentile die (1–100) |
| 4d6kh3 | keep the highest 3 of 4d6 |
| 4d6d1 | drop the lowest 1 die |
| 2d20kl1 | disadvantage – keep the lower d20 |
Formula
NdS + M: average = N(S + 1)/2 + M, range N + M to NS + M · 4d6kh3 (keep highest 3) averages 12.24 · 2d20kh1 = advantage
Worked example
Inputs — Roll: Type your own dice expression; Dice expression(s), separated by commas: 1d20+5, 2d6+3.
Results — Result (first expression) = 8; Dice rolled (first expression) = [3] + 5; Sum of all expressions = 18; Average of the first expression = 15.5; Chance of rolling this result or higher = 90 %; All rolls = Roll Dice Result Average Range
────────────────────────────────────────────────
1d20+5 [3] + 5 8 15.5 6 to 25
2d6+3 [2, 5] + 3 10 10 5 to 15.
Key terms
- Dice notation
- A shorthand such as 3d8+2: number of dice, d, number of sides, then modifiers.
- Keep highest (kh)
- Roll several dice and keep only the highest ones, e.g. 4d6kh3.
- Hit dice
- Dice used for hit points, e.g. d10 for fighters and d12 for barbarians.
Frequently asked questions
What does 2d6+3 mean?
Roll two six-sided dice and add 3. It averages 10 and ranges from 5 to 15.
How do I roll ability scores?
Use 4d6kh3 six times (preset "Ability scores"): roll four d6, drop the lowest. Each score averages about 12.24.
What dice are in a D&D set?
d4, d6, d8, two d10s (one for tens), d12 and d20.
How much damage does Fireball do?
8d6 fire damage: 28 on average, 8 to 48, with a standard deviation of about 4.8.
How do I write advantage in dice notation?
2d20kh1 – roll two d20s and keep the highest. Disadvantage is 2d20kl1.
What is the chance of rolling 18 on 4d6 drop lowest?
21 of the 1,296 outcomes give 18, about 1.62%.
Can I subtract dice?
Yes, for example 1d8-1d4; the result can be negative.