About this dice probability calculator
With more than one die, totals are not equally likely: with two six-sided dice there are six ways to make 7 but only one way to make 2 or 12, which is why 7 comes up most often. This calculator counts every way the dice can land, using exact whole-number arithmetic, so the result is exact rather than a simulation. It handles any number of dice up to 50 with 2 to 100 sides, a fixed modifier as in 3d8+5, and the tabletop RPG method of rolling four six-sided dice and dropping the lowest. Ask for exactly, at least, at most, more than, or less than a target, and read the answer as a percentage, a reduced fraction, odds, and how many rolls it takes on average.
How to calculate dice odds
- Describe the dice. Type notation such as 2d6 or 3d8+5, or set the number of dice, sides, and modifier yourself.
- Set the condition. Choose exactly, at least, at most, more than, or less than, and enter the target total.
- Press Calculate odds. Read the probability, fraction, and odds, and check the chart to see how likely every total is.
Frequently asked questions
Why is 7 the most common roll with two dice?
Six combinations make 7 (1+6, 2+5, 3+4, 4+3, 5+2, 6+1) out of 36, a 1 in 6 chance. Totals further from the middle have fewer combinations.
What does 3d8+5 mean?
Roll three eight-sided dice, add them up, and add 5. This notation is standard in Dungeons & Dragons and other tabletop games.
What is 4d6 drop lowest?
A common way to roll RPG ability scores: roll four six-sided dice and add the highest three. It averages about 12.24 instead of 10.5 for 3d6.
What is the difference between probability and odds?
Probability compares successes with all outcomes, such as 6 in 36 for a 7. Odds compare successes with failures, so the same roll is 1 : 5.
Is the result exact?
Yes. Every possible roll is counted with exact integer arithmetic, so the fraction is exact and the percentage is rounded only for display.