Dice Notation Explained: What "2d6+3" Means
The little codes on every spell and weapon, in plain English.
Open any tabletop rulebook and you'll trip over strings like 2d6+3, 1d20 or 4d8. They look cryptic, but the format is simple and always the same. Once it clicks, you can read any weapon, spell or trap at a glance — and roll it instantly on the dice roller.
The format: NdX+M
Every dice expression follows one pattern: NdX+M.
- N — how many dice to roll.
- d — just means "dice".
- X — how many sides each die has.
- +M — a flat modifier added (or subtracted) from the total.
So 2d6+3 reads as: "roll two six-sided dice, add them together, then add three." If you rolled a 4 and a 5, that's 9, plus 3, for a total of 12. The modifier is added once to the whole pool, not to each die.
Common dice and what they're for
- d20 — the big one. Almost every attack roll, saving throw and skill check is "1d20 + your bonus".
- d4, d6, d8, d10, d12 — damage and effects. A dagger might be 1d4, a greatsword 2d6, a fireball 8d6.
- d100 (also written d%) — percentile dice, for "roll under" tables and random results from 1 to 100.
Reading modifiers
A modifier can be positive or negative. 1d20+5 adds five (a skilled attack); 1d20−1 subtracts one (a penalty). When a character sheet says your attack bonus is +7, your roll is simply 1d20+7. You can also chain pools together: 1d20+2d6+5 is a hit (the d20) plus sneak-attack damage (2d6) plus a bonus (5) — though in practice you usually roll the to-hit and the damage separately.
Where advantage fits
"Advantage" isn't part of the notation — it's a rule layered on top. It means roll two d20s and keep the higher; disadvantage keeps the lower. It only ever applies to a single d20 check, never to damage pools. Our dice roller has a one-tap Advantage/Disadvantage toggle so you don't have to track both dice yourself.
- What does "d%" or "d100" mean?
- Percentile dice — a roll from 1 to 100. Physically it's two ten-sided dice (one for tens, one for ones); digitally it's just a single 1–100 result.
- Is 1d6 the same as d6?
- Yes. When N is left off, it's assumed to be 1. "d6" and "1d6" are identical.
- Does the modifier apply per die?
- No. In 2d6+3 you roll both d6s, total them, and add 3 once — not 3 to each die.