Ask most people to picture a die and they’ll think of a cube. Tabletop gaming uses a whole family of shapes, most of them the five “Platonic solids” whose faces are all identical — plus a few clever cheats for the numbers geometry won’t give you cleanly. Here’s the full cast.
The everyday dice
| Die | Shape | Commonly used for |
|---|---|---|
| d2 | A coin, or any die read odd/even | Straight coin-flip choices — left or right, yes or no |
| d3 | Usually a d6 read as 1–3 twice, or a rounded prism | Small random amounts — some spell and item effects |
| d4 | Tetrahedron (triangular pyramid) | Daggers, magic missile, small helper dice |
| d6 | Cube — the classic | Everything: damage, dice pools, board games |
| d8 | Octahedron | Common weapon damage, many hit dice |
| d10 | Pentagonal trapezohedron, numbered 0–9 | Percentile rolls, dice-pool systems, damage |
| d% (d100) | A second d10 marked 00–90 | Rolled with a d10 to give 1–100 |
| d12 | Dodecahedron | Big weapons (greataxe), the barbarian hit die |
| d20 | Icosahedron — the hobby’s icon | Attacks, saves, checks in d20 systems |
A note on the d2 and d3
You rarely buy these — they’re usually improvised. A d2 is just a coin, or a d6 where 1–3 means “low” and 4–6 means “high”. A d3 is most often a d6 with the result halved and rounded up (so 1–2 = 1, 3–4 = 2, 5–6 = 3). True prism-shaped d2 and d3 dice exist, but the fake versions are everywhere.
Why the d10 gets a partner
Two ten-sided dice make a d100. One is printed 00, 10, 20…90 (the tens) and the other 0–9 (the units). Read together they give 1–100, with a double-zero counting as 100. That pairing is why percentile-heavy games like Call of Cthulhu lean on the d10 so hard — more on that in our dice-by-system guide.
The oddities
Beyond the standard set live dice that geometry doesn’t hand over neatly, so makers get inventive:
- d16 — a bipyramid; occasionally used where a range of sixteen is wanted, or as a novelty.
- d24 — often a trapezohedron or tetrakis shape; niche, sometimes used for hours-of-the-day or fractional results.
- d30 — a rhombic triacontahedron, a genuinely useful oddball for tables of thirty entries or big single rolls.
- d100 Zocchihedron — the wild one. Designed by Lou Zocchi, it’s a near-spherical solid with 100 tiny faces that gives a true single-die 1–100. It rolls for ages and is more curiosity than workhorse, but it’s a beloved piece of dice history.
The opposite-faces rule
Pick up almost any standard die and add the number on top to the number directly underneath. On a well-made die, the two opposite faces sum to one more than the total number of sides:
- d6: opposite faces sum to 7 (1–6, 2–5, 3–4)
- d8: sum to 9
- d12: sum to 13
- d20: sum to 21
The reason is balance: pairing high with low across the die spreads the material and pip-weight as evenly as possible, which helps fairness. It also gives you a quick knock-off check — if a die’s opposite faces don’t add up, be suspicious. (For the deeper story on balance, see how dice are made fair.)
The d10 exception
The d10 breaks the pattern because it’s numbered 0–9 rather than 1–10. Its opposite faces sum to 9, not 11 — a direct consequence of starting at zero. It’s the one standard die where the “n+1” rule doesn’t apply, so don’t use that test to judge a d10.
Which do you actually need?
For nearly everything, the seven-dice polyhedral set is plenty. The oddities are for collectors, custom random tables and the joy of watching a Zocchihedron roll across the table for a full ten seconds. If you ever want a d16, d24 or d30 without hunting one down, a digital roller has them all — no shopping required.
Try it yourself. Dice Drop rolls real physics dice in your browser — every shape from d2 to d100, with advantage, modifiers and mixed pools built in.
🎲 Roll dice freeKeep reading: the best dice for every RPG system — which of these you’ll actually roll at your table.