When you think of dice, you probably picture a little cube with dots from one to six. That's the best-known one, but certainly not the only one. In board games, role-playing games, and casinos, people use dice with four, eight, ten, twelve, or even twenty faces. On this page I'll explain which types exist, what codes like D6 and D20 mean, and why some dice are Platonic solids while others aren't.
On this page
What does the "D" mean?
The codes D4, D6, D8, and so on come from the world of role-playing games. The "D" stands for dice, and the number after it is simply the number of faces. So a D6 is a die with six faces, a D20 one with twenty. Players also use the notation to write down rolls: 2D6 means "roll two six-sided dice and add them up".
The number of faces directly determines the range of outcomes. A D6 gives a number from 1 to 6, a D20 a number from 1 to 20. The more faces, the wider the range and the smaller the chance of any one specific outcome.
The standard die: the D6
The classic die you'll find in almost every board game is the D6: a cube with six faces and pips from one through six. This is the die you use to play Yahtzee, Parcheesi, Monopoly, and countless other games. Our online dice roller is a D6 too — and you can roll up to twelve at once.
The D6 is so popular because the cube shape is easy to make, sits stable, and rolls nicely across the table. Opposite the two you'll always find five pips: on a fair die, the pips on two opposite faces always add up to seven.
The polyhedral set: D4 through D20
In role-playing games like Dungeons & Dragons, one kind of die isn't enough. There you use a complete polyhedral set ("many-faced set") with different shapes, each for a different purpose. Such a complete set is also called a polydice set or simply DnD dice. The classic set consists of these dice:
- D4 — a four-faced die or tetrahedron, the pyramid-shaped one. Often used for light damage in a role-playing game.
- D6 — the familiar cube, indispensable in role-playing games too.
- D8 — an eight-faced die or octahedron, two pyramids joined base to base.
- D10 — a ten-faced die, often numbered 0 through 9.
- D12 — a twelve-faced die or dodecahedron with pentagonal faces.
- D20 — a twenty-faced die or icosahedron, the showpiece of every set.
The D20 is the most important in D&D: virtually every attack or skill roll starts with a throw of the twenty-sider. The D4 through D12 are mainly used to determine damage or effects. The D6 serves in role-playing games too, often in groups at a time.
The D100 or percentile roll
A set usually includes a second D10, numbered in tens (00, 10, 20 … 90). Together, those two ten-siders form the D100, also called the percentile roll. One die gives the tens, the other the units, so you get a number from 1 to 100. Two zeros together count as 100. You use it, for example, to determine a percentage chance in the game.
Reference table
Below are all the common dice with their shape, number of faces, and typical use.
| Type | Shape | Faces | Typical use |
|---|---|---|---|
| D4 | Four-faced (tetrahedron) | 4 | Damage and effects in role-playing games |
| D6 | Cube (six-sided) | 6 | Most board games |
| D8 | Eight-faced (octahedron) | 8 | Damage in role-playing games |
| D10 | Ten-faced (trapezohedron) | 10 | Tens and effects, 0–9 |
| D12 | Twelve-faced (dodecahedron) | 12 | Heavier damage in role-playing games |
| D20 | Twenty-faced (icosahedron) | 20 | Attack and skill rolls |
| D100 | Two D10s together | 100 | Percentages and probabilities, 1–100 |
Shape and fairness: the Platonic solids
A die is only fair if every face has exactly the same chance of landing face up. That's only possible if the die is fully symmetrical, so that no face gets favored. That's why most dice are based on the five Platonic solids: three-dimensional shapes in which all faces are identical and the same number of faces meets at every vertex.
Of the set, exactly five are Platonic solids: the D4 (tetrahedron), D6 (cube), D8 (octahedron), D12 (dodecahedron), and D20 (icosahedron). There are also no more than five Platonic solids — mathematically, no others are possible.
The exception: the D10 is not a Platonic solid but a trapezohedron — two crowns of five faces joined together. Its vertices and faces are not all alike. Even so, the D10 is a fair die, because all ten faces are the same size and shape and therefore have the same chance.
Want to know exactly how likely each outcome is? On the dice probability page I work it all out for the standard D6, including adding up multiple dice.
Special dice
Beyond the standard shapes, countless special dice exist. A few you'll run into more often:
- Fudge or Fate dice — six-sided dice whose faces aren't numbered but marked with a plus (+), a minus (−), or left blank (0). You usually roll four at once and add them up, for an outcome from −4 to +4.
- Averaging dice — D6s with modified pips (often 2-3-3-4-4-5) that produce less extreme outcomes and so stay closer to the average.
- Casino precision dice — sharp-edged, transparent dice with perfectly drilled pips, made to be as fair as possible for games like craps.
- Novelty dice — non-cubic dice with pictures, colors, or words instead of pips, for party games and kids' games.
No physical dice on hand? You don't need to buy or install anything: with the free online dice roller you can roll real 3D dice right in your browser. Curious where dice come from? Then also read the history of dice, or browse the best dice games to play.
Frequently asked questions about types of dice
What does D20 mean?
The "D" stands for "dice" and the number for the number of faces. So a D20 is a die with twenty faces — a twenty-sided solid, or icosahedron — that gives outcomes from 1 through 20.
How many dice are in a D&D set?
A standard polyhedral set contains seven dice: a D4, D6, D8, D10, D12, and D20, plus a second D10 for the tens. Together those two D10s form the D100, or percentile roll, from 1 to 100.
Is the D10 a Platonic solid?
No. The D4, D6, D8, D12, and D20 are the five Platonic solids, but the D10 is not — it's a trapezohedron. Still, the D10 is fair, because all ten faces are the same size and shape, so every face has the same chance.
Which die do you use for board games?
For most board games you use the ordinary six-sided die, the D6. It's the cube-shaped die with pips from 1 through 6 that you'll find in games like Parcheesi, Yahtzee, and Monopoly.