Polyhedral RPG Dice
Gaming Supplies · 11 specs
Direct Answer
Polyhedral dice are standardized 7-die sets used in tabletop role-playing games (TTRPGs) including Dungeons & Dragons and Pathfinder. A standard set consists of D4 (tetrahedron), D6 (cube), D8 (octahedron), D10 (pentagonal trapezohedron), D% (percentile tens), D12 (dodecahedron), and D20 (icosahedron), manufactured in standard 16 mm to 22 mm millimeter heights based on Platonic solids.
Source: Chessex / TTRPG Industry Polyhedral Standards · Last reviewed Aug 28, 2026
Specs
| Standard Set Composition | 7 Dice (D4, D6, D8, D10, D% tens, D12, D20) |
| D4 Shape & Height | Tetrahedron (4 triangular faces) 16 to 18 mm (vertex to base) |
| D6 Shape & Height | Cube (6 square faces) 16 mm (0.63 inches face-to-face) |
| D8 Shape & Height | Octahedron (8 triangular faces) 15 to 16 mm (face-to-face) |
| D10 / D% Shape & Height | Pentagonal Trapezohedron (10 kite faces) 16 mm (vertex-to-vertex) |
| D12 Shape & Height | Dodecahedron (12 pentagonal faces) 18 mm (face-to-face) |
| D20 Shape & Height | Icosahedron (20 triangular faces) 20 to 22 mm (face-to-face) |
| Opposite Faces Sum (D6) | 7 (1+6, 2+5, 3+4) |
| Opposite Faces Sum (D8) | 9 (1+8, 2+7, etc.) |
| Opposite Faces Sum (D12) | 13 (1+12, 2+11, etc.) |
| Opposite Faces Sum (D20) | 21 (1+20, 2+19, etc.) |
The 7-Die Standard RPG Set
Tabletop RPGs utilize Platonic solids (polyhedra with identical regular polygonal faces):
- D4 (4-sided): Caltrop tetrahedron. Numbers read either at the top apex or base edge.
- D6 (6-sided): Standard numbered cube.
- D8 (8-sided): Octahedron used for weapon damage (e.g., longsword, rapier).
- D10 & D% (10-sided): Pentagonal trapezohedrons. Rolled together as percentile dice (00–90 + 0–9 = 1 to 100%).
- D12 (12-sided): Dodecahedron used for barbarian hit dice and heavy greataxe damage.
- D20 (20-sided): Icosahedron, the core resolution die for attack rolls, saving throws, and skill checks in d20 systems.
Standard vs. Spindown D20 Dice
- Standard D20: Opposing faces always sum to 21 (1 is opposite 20), with high and low numbers distributed evenly around the sphere to prevent rolling bias.
- Spindown D20 (Life Counter): Used in Magic: The Gathering to track life totals. Adjacent faces are numbered sequentially (20 is adjacent to 19, 18, 17). Spindowns are NOT suitable for RPG rolling because imperfections can heavily bias the die toward high or low clusters.