What Does d20 Mean? Dice Notation Explained
Nov 7, 2026 · The Editors
What d20 means: the twenty-sided die, what 'd' stands for, dice notation like 2d6+3, how the d20 is used in Dungeons & Dragons, natural 20s and natural 1s, and d20 in online roleplay.
d20 means a twenty-sided die. The "d" stands for die, and the number after it is how many sides it has. So a d6 is an ordinary six-sided die, a d8 has eight sides, and a d20 has twenty.
Dice notation
Roleplaying games write dice rolls in a simple code:
| Notation | Means |
|---|---|
| d20 | Roll one twenty-sided die |
| 2d6 | Roll two six-sided dice and add them |
| 1d8+3 | Roll one eight-sided die and add 3 |
| 4d6, drop lowest | Roll four d6, ignore the lowest, add the rest |
| d% or d100 | Roll for a number from 1 to 100 |
The number before the d is how many dice to roll. The number after is how many sides. Anything after a plus or minus is added or subtracted.
The d20 itself
A d20 is an icosahedron: twenty identical triangular faces. Opposite faces add up to 21 on a standard die — 20 is opposite 1, 19 opposite 2 — so high and low numbers are spread evenly round the die.
What does d20 mean in D&D?
In Dungeons & Dragons and the many games built on the same system, the d20 is the most important die on the table. Whenever the outcome of something is uncertain, a player rolls a d20:
- Attack rolls — does your blow land?
- Ability checks — can you pick the lock, climb the wall, persuade the guard?
- Saving throws — do you resist the poison, dodge the fireball?
You add a modifier for your character's skill, and compare the total to a target number. Meet or beat it, and you succeed.
The other dice decide how much — damage, healing, the size of an effect. What each RPG die is for.
Natural 20 and natural 1
A natural 20 is a 20 on the die itself, before modifiers. In D&D an attack on a natural 20 is a critical hit, doing extra damage. Many tables treat a natural 20 as an automatic success on everything, and a natural 1 as an automatic failure — often a spectacular one. (The official rules apply this only to attacks and certain saves, but tables vary.)
"Nat 20" has become shorthand far beyond the game for a moment of perfect luck.
What does d20 mean in roleplay?
In online and text-based roleplay, "roll a d20" means letting chance decide what happens: roll a twenty-sided die (or a dice bot), and high numbers mean things go well, low numbers badly. It is the same idea, without the rules.
Why players love their d20s
The d20 is the die players have feelings about. Many keep a "lucky" d20, retire dice that roll too many 1s, and bring several to every session. A heavy metal d20 lands with a satisfying thud on a tray and reads clearly across the table — and a full set is one of the best gifts for a roleplayer. Choosing a set of dice.
