Dice Probability Calculator

Roll the virtual dice and crunch the numbers. Enter your dice type (D4 through D20), number of dice, and target value, then choose your probability condition — exact sum, sum at least, sum at most, or at least one die matching. Get back the probability percentage, odds ratio, and a full breakdown of all possible outcomes so you know exactly what to expect before you roll.

Select the type of die you are rolling.

How many dice are rolled at once.

Choose what outcome you want the probability for.

The number you want to roll (or the target sum across all dice).

Results

Probability

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Odds (1 in X)

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Favorable Outcomes

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Total Possible Outcomes

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Expected Average Roll (per die)

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Sum Probability Distribution

Results Table

Frequently Asked Questions

How do you calculate dice roll probability?

Dice probability is calculated by dividing the number of favorable outcomes by the total number of possible outcomes. For a single die with s sides, each face has a 1/s chance. For multiple dice, you count all combinations that produce the desired sum using a combinatorial formula, then divide by the total number of combinations (s raised to the power of n, where n is the number of dice).

How many possible outcomes are there when rolling two 6-sided dice?

There are 6 × 6 = 36 total possible outcomes when rolling two standard 6-sided dice. Each combination of face values is counted separately, so rolling a 1 and a 6 is different from rolling a 6 and a 1, giving 36 distinct results.

When rolling 2 dice, what is the probability of getting a sum of 7?

The probability of rolling a sum of 7 with two 6-sided dice is 6/36 = 16.67%. There are six combinations that produce a sum of 7: (1,6), (2,5), (3,4), (4,3), (5,2), and (6,1). This makes 7 the most likely sum when rolling two standard dice.

What is the probability of rolling a 6 on any given die roll?

For a standard 6-sided die, the probability of rolling a 6 is exactly 1/6, or approximately 16.67%. Each roll is an independent event, meaning previous results have no effect on future rolls. No matter how many times you roll, the odds of getting a 6 on a single die never change.

What polyhedral dice types are supported?

This calculator supports all common polyhedral dice used in tabletop games: D4 (4-sided tetrahedron), D6 (6-sided cube), D8 (8-sided octahedron), D10 (10-sided decahedron), D12 (12-sided dodecahedron), and D20 (20-sided icosahedron). These cover the full Dungeons & Dragons standard dice set.

What does 'at least one die equals target' mean?

This condition calculates the probability that one or more of your dice land on a specific face value. For example, rolling 3 six-sided dice and wanting at least one to show a 6. It's calculated using the complement rule: 1 minus the probability that none of the dice show the target value.

When is a dice probability calculator useful?

A dice probability calculator is useful when planning strategy in tabletop RPGs like D&D or Pathfinder, board games, or gambling games involving dice. Knowing the exact odds of a specific outcome helps you make informed decisions — for example, whether to attempt a risky action that requires rolling a high sum, or whether the odds favor a particular strategy.

What are the odds of rolling 38 or more with 3 six-sided dice?

Three 6-sided dice have a maximum sum of 18, so rolling a sum of 38 or more is impossible. If you meant a different dice type — for example, three D20s — the odds would be calculable using this tool by selecting D20, 3 dice, and the 'sum at least' condition with target 38.

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