Dice Probability Calculator

Calculate the probability of rolling a target sum.

Fill in the fields below to calculate

Number of Dice

Sides per Die

Target Sum (optional)

Enter your values above to see the result.

Your Results

Expected Value

Variance

Std. Deviation

Std Dev

Probability At Least

Formula

Expected Value:

E(X) = n × (s + 1) / 2

Variance:

Var(X) = n × (s² - 1) / 12

where n = number of dice, s = sides per die

Pro Tips

Results update as you type — change any field to see the effect immediately.

Check that every value uses the same unit before comparing results.

Use the copy button to paste the dice probability figures into a note or spreadsheet.

Nothing is sent to a server, so you can use this with private figures.

Probability Distribution