Quick Answer: Polyhedral dice are multi-sided dice used in tabletop role-playing games. The standard set includes 7 dice: d4 (4 sides), d6 (6 sides), d8 (8 sides), d10 (10 sides), d12 (12 sides), d20 (20 sides), and d100 (percentile, using two d10s). Each face has equal probability of 1/N.
The Full Polyhedral Dice Set
| Die | Faces | Shape | P(any face) | Common Uses |
|---|---|---|---|---|
| d4 | 4 | Tetrahedron | 25% | Small weapons, magic missile, wizard hit die |
| d6 | 6 | Cube | 16.67% | All board games, rogue/fighter hit die, most common die |
| d8 | 8 | Octahedron | 12.5% | Longsword, ranger/cleric hit die, spell damage |
| d10 | 10 | Pentagonal trapezohedron | 10% | Heavy weapons, fighter hit die, percentile |
| d12 | 12 | Dodecahedron | 8.33% | Greataxe, barbarian hit die |
| d20 | 20 | Icosahedron | 5% | Attack rolls, saving throws, D&D core mechanic |
| d100 | 100 | Two d10s | 1% | Wild magic, encounter tables, critical hit charts |
The d20: The Most Iconic RPG Die
The 20-sided die is the most recognized symbol of tabletop RPGs. In Dungeons & Dragons 5th Edition, the d20 is rolled for attack rolls (vs enemy Armor Class), ability checks (vs Difficulty Class), and saving throws. Rolling a natural 20 is a critical hit — a moment of triumph. Rolling a natural 1 is a critical failure — often causing dramatic failures or fumbles.
Advantage and Disadvantage (Two d20 System)
D&D 5e introduced a mechanic called Advantage/Disadvantage: roll two d20s and take the higher (Advantage) or lower (Disadvantage) result. Advantage effectively shifts the average roll from 10.5 to approximately 13.8. Disadvantage shifts it down to approximately 7.2. This is a significant swing that makes Advantage/Disadvantage one of the most impactful mechanics in the game.
Rolling Polyhedral Dice Online
PickRandom.online's 3D Dice Roller handles d6. For all other polyhedral dice, use the Random Number Generator with a custom range: set Min to 1 and Max to the number of faces. Each result uses CSPRNG — the same cryptographic standard as internet banking security.