Calculate dice probability for a specific total, all dice showing the same value, or at least one target face with exact ratio and percent.

Dice Probability Calculator

Dice Probability Formulas

The following formulas are used to calculate different dice probabilities (for fair 6-sided dice).

  1. Chance to roll a specific total sum (sum of all dice)
    1. C = N / 6^D
      • Where D is the number of dice
      • Where N is the number of ordered outcomes (rolls) that produce the target sum
  2. Chance all dice show a specific value (i.e. 1/1/1 on 3 dice)
    1. C = (1 / 6)^D
      • Where D is the number of dice
  3. Chance to roll at least one specific value on a roll of D dice (i.e. at least one 6)
    1. C = 1 – (5 / 6)^D
      • Where D is the number of dice

These formulas are written for 6-sided dice. For s-sided dice, replace 6 with s (so the denominators become s^D). For example: (1/6)^D becomes (1/s)^D, and 1 – (5/6)^D becomes 1 – ((s-1)/s)^D.

Dice Probability Definition

Dice Probability is defined as the chance of an event occurring while rolling 1 or more dice.

Dice Probability Example

How to calculate a dice probability?

First, determine the event or outcome you wish to calculate the probability of. In this example, we are examining the chance to roll 1/1/1 when rolling 3 dice (or the same die 3 times).

Next, choose the formula above that matches the probability event you are calculating and also decide the number of sides on the dice. In this case, the number of sides is 6 and the formula is:

C = (1 / 6)^D

C = (1 / 6)^3

C = 1/216 ≈ 0.00463 = 0.463% chance.

FAQ

What is the chance of rolling a number on dice?

For a fair 6-sided die, the chance of rolling a specific number (such as a 4) is 1/6, which is about 16.67%.