Standard dice come in seven sizes: d4, d6, d8, d10, percentile d10, d12, and d20. Five of them are Platonic solids, the d10 is a pentagonal trapezohedron, and percentile results come from rolling two d10s together. Beyond that set you’ll find a d2, a d3, a d30, and even a d120.
The five Platonic solids
Five shapes have faces that are all the same regular polygon, with the same number of faces meeting at every corner. Every one of them ended up as a die.
The tetrahedron is the d4. Four triangles, no top face, so you read the number at the point or along the bottom edge. The cube is the d6, the die sitting in every board game box you own. The octahedron is the d8, which looks like two square pyramids stuck base to base. The dodecahedron is the d12, twelve pentagons, the chunky one. And the icosahedron is the d20, twenty triangles, the die most people picture when someone says “polyhedral dice.”
Fair means every face is equally likely. Name a number on a d20 before you roll and your odds are 5%.
The d10 breaks the pattern
There’s no Platonic solid with ten faces. Ten identical regular polygons won’t close up into a solid, so the d10 uses a different shape: the pentagonal trapezohedron, made of ten kite-shaped faces. It has two sharp points where five kites meet and ten blunter corners where three meet. The shape was patented for use as a gaming die in 1906.
Most d10s run 0 through 9 rather than 1 through 10, which is what makes percentile rolls work. You roll a tens die marked 00, 10, 20 and so on up to 90 next to a units die, then read them together as a number from 00 to 99. Zero-zero counts as 100. Players call this a d100 or “percentile,” though no hundred-sided die is involved. Any single result comes up 1% of the time.
Dice outside the standard set
A d2 is a coin flip wearing a die costume, usually a d6 printed with three 1s and three 2s. Same trick for a d3: label a cube 1, 1, 2, 2, 3, 3. Specialty sets sometimes include a d16. The d30 is a rhombic triacontahedron, thirty rhombic faces, and it’s the only genuinely fair thirty-sided shape outside stretched barrel-style dice. The d120 is a disdyakis triacontahedron with 120 triangular faces. That’s the ceiling: 120 is the largest number of faces a fair die can have unless you count long dice and other stretched families.
If you’re buying one set, buy the seven-dice RPG set. It covers D&D rolls and almost every other tabletop game, and a pair of d6s handles the board game shelf.
Each die also has its own quirks worth knowing, from what the little dots are actually called to why the numbers on a d6 are arranged the way they are. The pages below go one die at a time, cover the words people argue about, and explain how NdM notation turns any of these shapes into a roll you can write down. You can also just roll them all here without digging a bag out of a drawer.
FAQ
How many types of dice are there?
The standard tabletop set has seven: d4, d6, d8, d10, a percentile d10, d12, and d20. Specialty makers add a d2, d3, d5, d7, d14, d16, d24, d30, d34, d48, d60, and d120. Only a handful of shapes are mathematically fair.
Why isn’t the d10 a Platonic solid?
No Platonic solid has ten faces. The five that exist have 4, 6, 8, 12, and 20 faces. To get ten equally likely results, dice makers use a pentagonal trapezohedron, ten kite-shaped faces arranged in two rings of five. It’s fair because every face is identical to every other face.
What is a d100 die?
Usually two d10s rolled together, one marked in tens and one in units, giving a number from 00 to 99 with 00 read as 100. Solid hundred-sided balls exist, sometimes called Zocchihedrons, but they roll forever and never caught on for real play.
Which dice do I need for Dungeons & Dragons?
One of each: d4, d6, d8, d10, percentile d10, d12, d20. That’s the standard seven-dice set sold everywhere. Spells and weapon damage often call for several of the same die at once, so many players carry extra d6s and a spare d20.
Is a d6 the same as a regular die?
Yes. A d6 is the six-sided cube used in Monopoly, Yahtzee, craps, and nearly every board game. The “d” stands for die and the number gives the face count, so d6 just names the shape you already know.