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Dice Roller,
d4 through d100.
Roll any combination of tabletop dice — d4, d6, d8, d10, d12, d20, and d100, with a flat modifier and up to four simultaneous die groups. Each roll shows individual results, the total, and a running history. Built for D&D, Pathfinder, Call of Cthulhu, and every other tabletop RPG.
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Dice roll
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1d20
Group 1
or press Enter
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Configure your dice above and click Roll Dice: or press Enter.
Tabletop dice guide
Understanding tabletop dice and when to use them.
Tabletop roleplaying games use polyhedral dice, so called because each die is a regular polyhedron (a 3-D solid with identical flat faces). The number after the "d" tells you how many faces it has: a d20 is an icosahedron with 20 faces numbered 1–20. Each roll gives a perfectly uniform result across its range.
The seven standard dice and what they're used for
| Die | Shape | Range | Common uses |
|---|---|---|---|
| d4 | Tetrahedron | 1–4 | Small weapon damage, wild magic surges |
| d6 | Cube | 1–6 | Most common die; swords, fireballs, hit dice |
| d8 | Octahedron | 1–8 | Versatile weapons, cleric hit dice |
| d10 | Pentagonal trapezohedron | 1–10 | Ranger/fighter damage, willpower saves |
| d12 | Dodecahedron | 1–12 | Barbarian hit dice, greataxe damage |
| d20 | Icosahedron | 1–20 | The core die, all ability checks, attacks, saving throws |
| d100 | Pentagonal trapezohedron ×2 | 1–100 | Percentile rolls, Wild Magic Table, encounter tables |
Dice notation: reading XdY+Z
Tabletop games describe dice rolls with a compact notation:
Examples:
- 2d6+3: roll two six-sided dice and add 3. Minimum result: 2 + 3 = 5. Maximum: 12 + 3 = 15.
- 1d20−2: roll one twenty-sided die and subtract 2. A roll of 7 becomes 5.
- 4d6: roll four six-sided dice and sum them. Standard D&D 5e character-stat generation (sometimes dropping the lowest of the four).
- 1d100: also written d% (percentile). In practice, two different d10s (one for tens, one for units) or a purpose-made d100 sphere.
Probability basics for dice rolls
Each face on a fair die is equally likely. The probability of rolling any specific value on a dN is 1/N. For multiple dice, the distribution of their sum follows a discrete probability distribution that becomes increasingly bell-shaped as you add more dice:
| Roll | Min | Max | Mean | Most common |
|---|---|---|---|---|
| 1d6 | 1 | 6 | 3.5 | Uniform, all equal |
| 2d6 | 2 | 12 | 7 | 7 (1-in-6 chance) |
| 3d6 | 3 | 18 | 10.5 | 10–11 (each ~12.5%) |
| 1d20 | 1 | 20 | 10.5 | Uniform, all equal |
| 4d6 | 4 | 24 | 14 | 14–15 (stat gen) |
The mean of a single dN roll is always (N+1) / 2. For a d6, that's 3.5. For a d20, it's 10.5. When rolling multiple dice, the means add: two d6 dice average 7, four d6 average 14.
Advantage and disadvantage (D&D 5e)
In D&D 5th Edition, some situations grant Advantage (roll 2d20, keep the higher) or impose Disadvantage (roll 2d20, keep the lower). This is not equivalent to a simple ±5 modifier — the effect is non-linear:
- No modification: Average 10.5, hit probability for DC 15 = 30%.
- Advantage: Average ~13.8, hit probability for DC 15 ≈ 51%.
- Disadvantage: Average ~7.2, hit probability for DC 15 ≈ 9%.
To roll with advantage using this calculator: set quantity to 2d20, read the higher of the two results. For disadvantage, read the lower.
Common tabletop RPG roll scenarios
- D&D 5e attack roll: 1d20 + proficiency + ability modifier. Hit if result ≥ target's Armour Class. Critical hit on a natural 20 (the die face, not the total).
- Pathfinder 2e skill check: 1d20 + level + relevant ability + proficiency rank + any circumstance bonuses.
- Call of Cthulhu skill roll: 1d100 — succeed if result is ≤ your skill value. A roll of 01–05 is always a Critical Success; 96–100 is always a Fumble.
- Shadowrun dice pool: Roll a number of d6s equal to your dice pool. Count each 5 or 6 as a "Hit." Need a certain number of Hits to succeed.
- GURPS: Roll 3d6 against your skill attribute. Succeed if the result is ≤ your skill. 3–4 always succeeds, 17–18 always fails.
How this roller generates random numbers
This calculator uses the browser's crypto.getRandomValues(), the same cryptographically secure pseudorandom number generator (CSPRNG) used for generating encryption keys and passwords. Every face of every die has an exactly equal probability of appearing. The random source is seeded from hardware entropy, making it much more fair than a simple Math.random() call.
For a dN die, the method works by drawing a random 32-bit unsigned integer and taking the remainder after dividing by N, giving a perfectly uniform distribution over [1, N].