D12 Roller
Roll a virtual d12 — a dodecahedron with twelve pentagonal faces, the roundest-rolling of the Platonic dice. Every face lands with an equal 1-in-12 probability and an average roll of 6.5, generated with cryptographic randomness in your browser. The d12 is a dodecahedron — twelve pentagon faces that make it roll almost like a ball and stop more decisively than a d20. Despite being in every polyhedral set since the 1970s, it is famously the least-used die in the bag, which has become a running joke among roleplayers.
D12 Roller reference last updated · reference source
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Dated static reference; no live data is fetched. Verify current source values and assumptions before relying on results.
What this tool does
Roll a virtual d12 — a dodecahedron with twelve pentagonal faces, the roundest-rolling of the Platonic dice. Every face lands with an equal 1-in-12 probability and an average roll of 6.5, generated with cryptographic randomness in your browser. The d12 is a dodecahedron — twelve pentagon faces that make it roll almost like a ball and stop more decisively than a d20. Despite being in every polyhedral set since the 1970s, it is famously the least-used die in the bag, which has become a running joke among roleplayers.
How to use the D12 Roller
- Check Sides per die: 12.
- Check Dice count: 1.
- Review the D12 Roller result and its exact-value comparison table.
- Verify assumptions before applying the result.
Formula
each die is a uniform integer from 1 through sides, using Web Crypto
- sides
- Sides per die
- count
- Dice count
Independent virtual dice. Generate again to reroll.
Worked example
D12 Roller: Sides per die = 12; Dice count = 1. Roll a virtual d12 — a dodecahedron with twelve pentagonal faces, the roundest-rolling of the Platonic dice. Every face lands with an equal 1-in-12 probability and an average roll of 6.5, generated with cryptographic randomness in your browser. The d12 is a dodecahedron — twelve pentagon faces that make it roll almost like a ball and stop more decisively than a d20. Despite being in every polyhedral set since the 1970s, it is famously the least-used die in the bag, which has become a running joke among roleplayers.
Inputs
- Sides per die12
- Dice count1
Result
- Total10
- Rolls10
- Expected total (average over many rolls)6.5
- Minimum possible total1
- Maximum possible total12
- Chance of the maximum total8.333%
- Chance each single die shows its top face8.333%
D12 quick odds
| Question | Answer |
|---|---|
| Average roll | 6.5 |
| Chance of any single face | 1 in 12 (8.333%) |
| Chance of rolling the maximum (12) | 1 in 12 |
| Chance of rolling above the average (over 6.5) | 6 in 12 (50%) |
| Faces | 12 |
Results explained
- Total
- The sum of the independent d12 rolls shown, each a uniform integer from 1 to 12.
- Rolls
- The individual die results in the order rolled.
- Expected total (average over many rolls)
- Dice count × 6.5, the theoretical average for a d12.
- Chance of the maximum total
- The probability that every die in the roll shows 12 at once: (1/12)^count.
Frequently asked questions
Dungeons & Dragons reserves the d12 for its biggest single-die jobs: the barbarian's hit die (the only class with one) and greataxe damage, plus a few high-level spells. Its scarcity is the point — when the d12 comes out, something heavy is happening.
(12 + 1) ÷ 2 = 6.5. Every face from 1 to 12 is equally likely, so the long-run average sits exactly halfway between the minimum and maximum.
Exactly 1 in 12, or 8.333%, on a single die. With two dice both showing 12 the chance drops to 1 in 144 (0.6944%).
Yes. Rolls come from the Web Crypto API with rejection sampling, so no face is favoured by modulo bias, and nothing is weighted, seeded from the clock or influenced by previous rolls.
Because so few effects use it, a d12 is statistically the freshest die in most sets — and its 6.5 average makes it the natural step between the common d10 (5.5) and the rare d20 (10.5) in damage ladders.
Yes — raise the dice count (gamers write that as 2d12, 3d12 and so on). Totals then follow a bell curve centred on 6.5 per die: extremes get rarer as you add dice, which is why multi-dice rolls feel more predictable than a single big die.