How to use the dice probability calculator
Find the chance of a total on one or two dice. Enter target sum, sides per die in the fields above; the ways to roll the sum, probability, probability are computed instantly and plotted on the chart so you can see how the answer changes.
Formula
Variables
- t — Target sum
- s — Sides per die
Worked example
With target sum = 7, sides per die = 6, the calculator gives ways to roll the sum ≈ 6; probability ≈ 0.1666667; probability ≈ 16.66667 %.
Frequently asked questions
What is the formula for the dice probability calculation?
Ways to roll the sum = max(0,min(t-1,s,2 × s+1-t)). Probability = [Ways to roll the sum] / (s × s). Probability (%) = 100 × [Probability]. Here t is target sum, s is sides per die.
What inputs do I need for the dice probability calculator?
You need target sum, sides per die. Each field is pre-filled with a typical example so you can see how the result responds as you edit the numbers.
How do I use this calculator?
Type values into the input fields. Results and the chart update instantly. Use Reset to restore the example values, Copy results to paste them elsewhere, or Share to copy a link that preserves your inputs.
Is the result exact?
Calculations use standard formulas and double-precision arithmetic, then display about seven significant figures. Real-world measurements carry uncertainty, so treat results as estimates unless your inputs are exact.