Tabletop RPG Dice: Types, Uses, and How to Read Them

A standard polyhedral dice set contains 7 individual dice, each with a distinct shape, a different number of faces, and a specific job at the table. Understanding what each one does — and when it gets rolled — is one of the first practical skills any new player needs, and one that experienced players still reference when switching between systems. This page covers the full set of standard dice, explains how probability and notation work, and maps out which dice appear in which game contexts.

Definition and scope

The polyhedral dice used in tabletop RPGs are not a single tool but a coordinated system. The standard set, first popularized through Dungeons & Dragons after its 1974 publication by Gary Gygax and Dave Arneson, includes 7 dice designated by the letter d followed by their face count: d4, d6, d8, d10, d12, d20, and d00 (the percentile die). That final pair — a d10 numbered 0–9 and a d00 numbered 00–90 in tens — works together to generate a result from 1 to 100.

Each die is a specific Platonic or Archimedean solid. The d4 is a tetrahedron, the d6 a cube, the d8 an octahedron, the d12 a dodecahedron, and the d20 an icosahedron. The d10 is technically a pentagonal trapezohedron — not a Platonic solid, which is why it rolls so dramatically across the table when given half a chance.

Dice notation follows a consistent format: [number of dice]d[faces] + [modifier]. So "2d6+3" means roll two six-sided dice and add 3 to the total. The notation is standardized enough across games that it functions as a shared language between systems.

How it works

Every roll produces a random integer within a defined range, and the game's rules assign meaning to that number. The mechanism is simple; the design choices built around it are not.

The d20 is the resolution engine in D&D 5th Edition (Player's Handbook, Wizards of the Coast). Attack rolls, ability checks, and saving throws all use a d20. A player rolls, adds a relevant modifier (which can range from -5 to +11 at first level in 5e, depending on the stat and proficiency), and compares the result to a target number called a Difficulty Class (DC) or Armor Class (AC). Roll equal to or above: success. Below: failure.

The probability behavior of each die shapes player experience in distinct ways:

1. d4 — Produces results of 1, 2, 3, or 4 with equal 25% probability each. Used primarily for small weapon damage (daggers, magic missiles) and some healing spells.
2. d6 — The most familiar die outside RPGs. Used for medium weapons (shortswords, handaxes), the hit points of sorcerers in 5e, and as the primary resolution die in games like GURPS and many Powered by the Apocalypse titles.
3. d8 — Standard for longswords, rapiers, and cleric hit points in 5e. Also appears as the base damage die in multiple class features.
4. d10 — Used for heavy melee weapons, fighter hit points (10 per level in 5e), and paired with a d00 for percentile rolls.
5. d12 — The least-rolled die in most sessions. Greataxes deal d12 damage; the barbarian class uses d12 for hit points. It appears rarely enough that some tables call it "the lonely die."
6. d20 — The signature die of D&D. A natural 20 (the highest face result before modifiers) typically triggers a critical hit.
7. d100 / percentile — Used for wild magic surges, loot tables, and older-edition systems like Call of Cthulhu, where skill checks are resolved as percentages.

Common scenarios

A sword-and-sorcery combat round in D&D 5e might involve: a d20 for the attack roll, a d8 for the longsword's damage, a d6 added to that damage from a Sneak Attack ability, and a d4 for a Bless spell's bonus on a saving throw — all within 60 seconds of real time. Players who build characters through character creation quickly learn which dice their character uses most often.

In Pathfinder 2nd Edition (Paizo Publishing), the dice system is nearly identical in structure but introduces the concept of multiple attack penalties, changing when and how often d20s get rolled per turn.

Call of Cthulhu (7th Edition, Chaosium) is almost entirely percentile-based. A character with a 60% skill in Firearms rolls d100 and hopes to land at 60 or below. The d20 barely appears. This illustrates how the same physical object carries different weight across systems — a contrast worth understanding before choosing a first RPG system.

Dice also generate non-combat content: random encounter tables, NPC personality traits, weather conditions, and treasure rewards all typically use d6, d8, d10, or d100, depending on how many options the table contains.

Decision boundaries

Choosing which die to roll is always the game's job, not the player's — the rules specify it. The player's actual decision space involves modifiers and when to trigger abilities that change roll outcomes.

The key contrasts that matter at the table:

• High variance vs. low variance: A d20 has a flat 5% probability per face, making swings dramatic and unpredictable. Pools of d6s (as used in Shadowrun or Blades in the Dark) cluster results toward the middle through averaging, making outcomes more predictable as pool size grows.
• Single die vs. dice pool: D&D uses single-die resolution for most checks. Games like World of Darkness roll pools of d10s and count successes, which changes the math and the feel entirely.
• Advantage/Disadvantage vs. modifiers: 5e's Advantage system (roll 2d20, keep the higher) shifts the effective average from 10.5 to approximately 13.8 — a concrete mechanical benefit without touching the modifier track.

Players exploring what gear and components to bring to a session will find that a single 7-piece set covers the mechanical demands of most major systems. The full landscape of what tabletop RPG play looks like — systems, settings, and beyond — is outlined on the main reference index.