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. This page covers which dice 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 letter "d" stands for die or dice, and the number after it is the number of faces. So a d6 is a die with six faces, a d20 one with twenty. You will see it capitalized here and there, but lowercase is what rulebooks and virtual tabletops print, so that is what this site uses.
Players write whole rolls in that same shorthand: 2d6 means "roll two six-sided dice and add them up". Dice notation explained →
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 many other games. Our online dice roller rolls it in 3D, along with every other type on this page: d2, d3, d4, d8, d10, d12, d20, the percentile tens die, and Fudge dice, up to twelve on the table at once. Each die gets its own type and its own color, picked one by one with the pencil button next to the roll button. Roll two d6 online →
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. It has no face pointing up when it lands, so you read it another way: most d4s repeat each number at the corners and you take the one at the top point, while others print the numbers along the edges and you read the row around the base. Roll a d4 online →
- d6: the familiar cube, indispensable in role-playing games too. Roll a d6 online →
- d8: an eight-faced die or octahedron, two pyramids joined base to base. Roll a d8 online →
- d10: a ten-faced die, often numbered 0 through 9, where the 0 counts as 10 when you roll it on its own. Roll a d10 online →
- d12: a twelve-faced die or dodecahedron with pentagonal faces. Roll a d12 online →
- d20: a twenty-faced die or icosahedron, the best-known die in the set. Roll a d20 online →
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 several at a time: the classic way to roll up an ability score is 4d6, drop the lowest. Roll 4d6 online →
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, and you use it wherever a game asks for a percentage chance.
Decide before you throw which die is which: the tens die gives the first digit, the units die the second. A 30 and a 7 is 37. A 00 and a 7 is 7. A 90 and a 0 is 90. If both your dice run 0 through 9, designate one of them as the tens die and multiply its result by ten in your head. It's the same roll with more work, which is why sets include a die already printed in tens.
Remember one case: 00 and 0 together. That pair reads as 100, the top of the range, not as 0. That's the rule in D&D and in most percentile systems. It isn't universal, though. Some games read the two dice literally as a 0-to-99 range instead, so a 00 and a 0 is 0 there. When a game uses percentile rolls a lot, check which of the two ranges its rules use.
You can throw a percentile pair here too. The roller has a real tens die with 00 through 90 on its faces, so you read the pair off the table the way you would read your own dice. Roll a percentile pair online →
Reference table
Below are all the common dice with their shape, number of faces, and typical use, plus a link that puts each one straight onto the table in the roller.
| Type | Shape | Faces | Typical use | Roll it online |
|---|---|---|---|---|
| d4 | Four-faced (tetrahedron) | 4 | Damage and effects in role-playing games | Roll a d4 → |
| d6 | Cube (six-sided) | 6 | Most board games | Roll a d6 → |
| d8 | Eight-faced (octahedron) | 8 | Damage in role-playing games | Roll a d8 → |
| d10 | Ten-faced (trapezohedron) | 10 | Tens and effects, 0–9 | Roll a d10 → |
| d12 | Twelve-faced (dodecahedron) | 12 | Heavier damage in role-playing games | Roll a d12 → |
| d20 | Twenty-faced (icosahedron) | 20 | Attack and skill rolls | Roll a d20 → |
| d100 | Two d10s together | 100 | Percentages and probabilities, 1–100 | Roll a percentile pair → |
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 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.
The dice probability page works out how likely each outcome is for the standard d6, including adding up multiple dice.
Special dice
Beyond the standard shapes, many 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. Roll four Fudge dice online →
- 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 3D dice right in your browser, and the free Android app gives you the same per-die type and color picker with the dice up on your TV. Rather improvise with whatever is lying around the house? Then see what to use instead of dice. 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 letter "d" stands for "die" or "dice", and the number after it is how many faces the die has. 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.
How do you roll a d100?
You roll two ten-sided dice: one numbered in tens (00, 10, 20 … 90) for the first digit, and an ordinary d10 for the second. A 30 and a 7 is 37. The pair 00 and 0 is read as 100, the top of the range, not as 0. That's the rule in D&D and most percentile systems, though a few games treat the pair as a 0-to-99 range instead, so check the rules you're playing by.
Can I roll polyhedral dice online?
Yes. The dice roller on this site throws d2, d3, d4, d6, d8, d10, d12, d20, the percentile tens die, and Fudge dice in 3D, up to twelve at a time. Every die on the table has its own type and its own color, which you pick per die with the pencil button next to the roll button.
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.