Polyhedral dice

In a wide variety of role playing games, a number of polyhedral dice are used. The commonest are in the shapes of the five Platonic solids.

Typically, these dice are referred to by the number of faces they have: a 'd6' is a regular cubic die, pronounced 'dee-six'.

Common Dice:

Sides Shape Notes Platonic

d4 tetrahedron Each face has three numbers: they are arranged such that the top number is the same on all three visible faces. Yes

d6 cube A common die. Opposite faces must add to seven. Yes

d8 octahedron Each face is triangular; looks something like two Egyptian pyramids attached at the base. Yes

d10 Irregular decahedron;
see Dice/10-sided dice Each face is kite-shaped; the smallest angle of five faces point to one edge, the smallest angle of the other points to the opposite. Not a regular polyhedron. Often, all odd number are on one half of the die and all even faces are on the other half. No

d12 dodecahedron Each face is a regular pentagon. Yes

d20 icosahedron Faces are equilateral triangles. Typically, opposite faces add to twenty-one. Yes

Sides	Shape	Notes	Platonic
d4	tetrahedron	Each face has three numbers: they are arranged such that the top number is the same on all three visible faces.	Yes
d6	cube	A common die. Opposite faces must add to seven.	Yes
d8	octahedron	Each face is triangular; looks something like two Egyptian pyramids attached at the base.	Yes
d10	Irregular decahedron; see Dice/10-sided dice	Each face is kite-shaped; the smallest angle of five faces point to one edge, the smallest angle of the other points to the opposite. Not a regular polyhedron. Often, all odd number are on one half of the die and all even faces are on the other half.	No
d12	dodecahedron	Each face is a regular pentagon.	Yes
d20	icosahedron	Faces are equilateral triangles. Typically, opposite faces add to twenty-one.	Yes

Uncommon Dice:

Sides Shape Notes

d7 A very uncommon die type, it's shaped as a pentagonal prism, thick enough to land either on its "edge" or "face". When landing on an edge, the topmost edge has pips for 1 through 5. The pentagonal faces are labeled with the digits 6 and 7.

d30 Each face is in the shape of a rhombus (diamond-shaped).

d100
d% Trade name: Zocchihedron Usually modelled by rolling two d10, one labelled 00,10,20..90, the other normal. Examples do exist of 'true' d100's, but these are rare, and given the nickname death stars due to a passing resemblance to the Star Wars ship. Other d100s may be in the shape of a golf ball.

Sides	Shape	Notes
d7		A very uncommon die type, it's shaped as a pentagonal prism, thick enough to land either on its "edge" or "face". When landing on an edge, the topmost edge has pips for 1 through 5. The pentagonal faces are labeled with the digits 6 and 7.
d30		Each face is in the shape of a rhombus (diamond-shaped).
d100 d%	Trade name: Zocchihedron	Usually modelled by rolling two d10, one labelled 00,10,20..90, the other normal. Examples do exist of 'true' d100's, but these are rare, and given the nickname death stars due to a passing resemblance to the Star Wars ship. Other d100s may be in the shape of a golf ball.

Often the names of the dice appear in formulas for calculating game parameters: e.g., hit points. '6d8+10', for example, will yield a number between 16 (6×1+10) and 58 (6×8+10) with a bell curve distribution, as it means 'Roll an eight-sided die six times and add ten to the total of all the rolls'. Occasionally they may be written '10×d6+20' or '1d6×10+20'; this means 'roll one six-sided die. Multiply it by ten and add twenty', and avoids boring repetitive dice-rolling at the expense of generating a bell curve distribution.