Custom Dice Probability Calculator – Roll Smarter Every Time
🎲 Custom Dice Probability Calculator
Calculate exact probabilities, averages, and distributions for any dice combination
⚡ Quick Presets
🎮 Dice Configuration
📊 Probability Results
🎲 Dice Quick Stats
3.5
d6 Average Roll
16.7%
2d6 Rolls a 7
5%
d20 Natural 20
12.24
4d6 Drop 1 Avg
50%
d6 Rolls 4+
58.3%
2d6 Rolls 6+
0.46%
5d6 Full Yahtzee
10.5
d20 Average Roll
📊 Dice Probability Distribution Table
| Dice Type | Sides | Min | Max | Average | Prob Any Specific | Prob Rolling Max |
|---|---|---|---|---|---|---|
| d4 | 4 | 1 | 4 | 2.5 | 25.0% | 25.0% |
| d6 | 6 | 1 | 6 | 3.5 | 16.7% | 16.7% |
| d8 | 8 | 1 | 8 | 4.5 | 12.5% | 12.5% |
| d10 | 10 | 1 | 10 | 5.5 | 10.0% | 10.0% |
| d12 | 12 | 1 | 12 | 6.5 | 8.3% | 8.3% |
| d20 | 20 | 1 | 20 | 10.5 | 5.0% | 5.0% |
| d100 | 100 | 1 | 100 | 50.5 | 1.0% | 1.0% |
| 2d6 | — | 2 | 12 | 7.0 | — | 2.78% |
| 3d6 | — | 3 | 18 | 10.5 | — | 0.46% |
| 4d6 | — | 4 | 24 | 14.0 | — | 0.077% |
🎮 Common Game Dice Scenarios
| Game | Dice Used | Key Roll | Probability | Avg Outcome | Players |
|---|---|---|---|---|---|
| Catan | 2d6 | Roll 6 or 8 | 27.8% | 7 | 3–6 |
| Craps (Pass) | 2d6 | Roll 7 or 11 | 22.2% | 7 | 2–20 |
| Yahtzee | 5d6 | Yahtzee (5-kind) | 0.077% | — | 1–4 |
| D&D Attack (d20) | 1d20 | Hit AC 15 | 30% | 10.5 | 1–6 |
| Risk (Attack 3v2) | 3d6 vs 2d6 | Attacker wins both | 37.2% | — | 2–6 |
| Monopoly | 2d6 | Doubles | 16.7% | 7 | 2–8 |
| Warhammer 40K | Nd6 | Hit on 4+ | 50% | — | 2 |
| Fate/Fudge | 4dF | Roll +4 | 1.23% | 0 | 1–5 |
📈 2d6 Full Probability Distribution
| Sum | Ways to Roll | Exact Probability | At Least This Sum | At Most This Sum | Catan Hex |
|---|---|---|---|---|---|
| 2 | 1 | 2.78% | 100% | 2.78% | — |
| 3 | 2 | 5.56% | 97.2% | 8.33% | — |
| 4 | 3 | 8.33% | 91.7% | 16.7% | — |
| 5 | 4 | 11.1% | 83.3% | 27.8% | 4 dots |
| 6 | 5 | 13.9% | 72.2% | 41.7% | 5 dots |
| 7 | 6 | 16.7% | 58.3% | 58.3% | — |
| 8 | 5 | 13.9% | 41.7% | 72.2% | 5 dots |
| 9 | 4 | 11.1% | 27.8% | 83.3% | 4 dots |
| 10 | 3 | 8.33% | 16.7% | 91.7% | — |
| 11 | 2 | 5.56% | 8.33% | 97.2% | — |
| 12 | 1 | 2.78% | 2.78% | 100% | — |
📏 Standard Dice Physical Dimensions
| Dice Type | Shape | Size (in) | Size (mm) | Common Use | Typical Set Count |
|---|---|---|---|---|---|
| d4 | Tetrahedron | 0.63" | 16mm | D&D Damage | 4 per set |
| d6 | Cube | 0.63" | 16mm | Universal | 6 per set |
| d8 | Octahedron | 0.71" | 18mm | D&D Damage | 2 per set |
| d10 | Pentagonal Trapezohedron | 0.71" | 18mm | Percentile/RPG | 2 per set |
| d12 | Dodecahedron | 0.79" | 20mm | D&D/RPG | 1 per set |
| d20 | Icosahedron | 0.87" | 22mm | D&D Core | 1 per set |
| d100 (Percentile) | Pentagonal Trapezohedron | 0.71" | 18mm | RPG Percentile | 2 per set |
| Fudge/Fate (dF) | Cube (modified) | 0.63" | 16mm | Fate RPG | 4 per set |
💡 Probability Tip: When rolling multiple dice, the distribution becomes bell-shaped (normal). With 2d6 the most common result is 7 (16.7%), but with a single d12 all results have equal 8.3% probability — very different game feel despite the same range.
💡 D&D Stat Generation: The "4d6 drop lowest" method produces an average of 12.24 per stat, compared to 10.5 for a straight 3d6 roll. This is why it produces notably stronger characters. For ability checks, add your modifier to d20 and compare to the Difficulty Class (DC).
AnyDice is strong on-line calculator for probabilities of dice. It was born specifically for roleplaying games. That free utility answers for RPG, D&D and many alike games.
It helps to find probabilities for various parts of cubes. For instance, it estimates chance in two 6-sided cubes give certain amount. The utility operates with all kinds of dice, of the 6-sided D6 after the 4-sided D4 until the 20-sided D20.
AnyDice — Easy Online Dice Chance Calculator for RPGs
Calculators that do for regular and special dice. They estimate chance in precise result or expect value. They are useful in games about silliness.
So you can estimate exactly the chance in certain number. Or the probability for amount less or more than particular value. In game with two D20 because of advantage or disadvantage, it shows when both give same number.
Also it is possible to estimate chance in certain number or more from usual cubes. For example cubes of L5R either FFG Genesys.
The key rule is compare possible results with the wanted. For colour on one cube, you share occasions of it by means of sides. For something as BCP, probability is B × C × P. Rolling three D6, you wants to know chance in certain amount of two from them at least once.
Designing RPG, matter that mechanics make sense. Utility helps that control. One mode for combinations: consider all from three cubes as sides of 216-sided cube.
Program then does rate for estimate success. Complextity grow when you add more cubes. With third cube failure requires two from them be invalid during the third can be anything.
