Dice Roller
Roll DnD dice online instantly — roll a d4, d6, d8, d10, d12, d20, or custom polyhedral dice. Powered by cryptographically secure randomness for D&D, Pathfinder, and tabletop gaming.
Dice Shapes & the Polyhedral Set
Standard tabletop RPGs use a set of Platonic solids and related polyhedra where every face has an equal probability of landing face-up. The classic seven-die set used in Dungeons & Dragons consists of the d4, d6, d8, d10, d12, d20, and d100 (percentile).
| Die | Shape | Faces | Face Geometry | Common Uses |
|---|---|---|---|---|
| d4 | Tetrahedron | 4 | 4 triangular faces | D&D damage (small weapons), Pathfinder |
| d6 | Cube | 6 | 6 square faces | Most board games, Yahtzee, Catan, basic D&D |
| d8 | Octahedron | 8 | 8 triangular faces | D&D longsword/crossbow damage |
| d10 | Pentagonal Trapezohedron | 10 | 10 kite-shaped faces | D&D, percentile rolls (d100 = 2×d10) |
| d12 | Dodecahedron | 12 | 12 pentagonal faces | D&D greataxe damage, Barbarian hit dice |
| d20 | Icosahedron | 20 | 20 triangular faces | Core D&D attack/skill checks, saving throws |
| d100 | Zocchihedron / 2×d10 | 100 | 100 faces (or two d10s) | Percentile tables, Wild Magic Surge |
How Random Is a Virtual Dice Roll?
This is a genuinely interesting question with a nuanced answer. Physical dice have physical imperfections — injection-molded plastic dice can have internal air bubbles, uneven pip depths (more ink = slightly heavier face), and rounded corners that all introduce tiny, measurable biases. Casino-grade precision dice (machined to ±0.001 inch tolerance) are significantly fairer, but even those aren't mathematically perfect.
Virtual dice, meanwhile, depend entirely on their random number generator. Most online dice rollers use JavaScript's Math.random(), which is a deterministic pseudo-random algorithm (the Xorshift128+ or similar PRNG in most browsers). It appears random for human perception but is technically predictable if you know the seed.
Math.random() for any use case where fairness matters.Additionally, this calculator uses rejection sampling to eliminate modulo bias — a subtle bug in naive implementations where values near the top of a random integer range appear slightly less often than values near the bottom. Every face on every die here has exactly equal probability.
Rolling Multiple Dice at Once
The notation NdX means "roll N dice, each with X sides, and add the results." Common examples in D&D 5th Edition:
2d6 — standard roll for short sword damage, greatsword with Great Weapon Fighting. 4d6 drop lowest — ability score generation (roll four d6s, drop the lowest result). 8d6 — Fireball spell damage. 1d20 + modifier — the fundamental attack/skill check mechanic of the entire D&D system.
Quick-Reference: Dice Probability
Because each face of a fair die is equally likely, the probability of any single outcome on a dN is exactly 1/N. The expected value (average roll) is (N+1)/2 — so a d20 averages 10.5, a d6 averages 3.5, and a d12 averages 6.5. Rolling multiple dice makes results converge toward the middle of the range (central limit theorem), which is why 4d6 ability scores cluster around 12-14 rather than spiking at 4 or 24.