Table of Contents
Standard Polyhedral Dice
Polyhedral dice are the standard set used in tabletop RPGs: d4 (tetrahedron), d6 (cube), d8 (octahedron), d10 (pentagonal trapezohedron), d12 (dodecahedron), and d20 (icosahedron). Each provides a uniform distribution where every face is equally likely.
These dice have been used in gaming since the 1970s with the original Dungeons & Dragons. The d20 determines success/failure on most actions, while other dice determine damage, healing, and random effects.
Dice Types
| Die | Faces | Average | Common Use |
|---|---|---|---|
| d4 | 4 | 2.5 | Small weapon damage |
| d6 | 6 | 3.5 | Standard damage, ability scores |
| d8 | 8 | 4.5 | Medium weapon damage |
| d10 | 10 | 5.5 | Large weapon damage, percentile |
| d12 | 12 | 6.5 | Heavy weapon damage |
| d20 | 20 | 10.5 | Attack rolls, checks, saves |
Probability Basics
Each face on a fair die has equal probability. A d6 gives each number 1/6 (16.67%) chance. Multiple dice create bell-curved sum distributions.
RPG Usage
In D&D 5e, a longsword deals 1d8 slashing damage (avg 4.5). A greatsword deals 2d6 (avg 7). A fireball deals 8d6 (avg 28). Understanding dice averages helps players make tactical combat decisions.
Frequently Asked Questions
What is the standard RPG dice set?
A standard set contains one each of d4, d6, d8, d10, d10 (percentile), d12, and d20. Many players also carry extra d6s for damage rolls.
How do I read a d4?
D4s are read differently from other dice. The number at the top point or the number at the base (depending on design) is the result. Modern d4s typically use numbers at the top.
Can loaded dice change probabilities?
Yes. Weighted or shaved dice alter the probability distribution. Casino dice are precision-manufactured to prevent this, while novelty "loaded" dice intentionally bias results.