Probability Calculator

Calculate combinations, permutations, and combined independent probabilities.

Probability Calculator helps you combinations, permutations, and a simple independent event probability. Enter n and k, review the breakdown, and use the guidance below to understand what the number means — and what it does not. What the Probability calculator does Probability Calculator is built for arithmetic, algebra, geometry, and number tools. Combinations, permutations, and a simple independent event probability. You enter n and k, then Simple Calculators computes the result instantly. Results use standard school and engineering formulas that run privately in your browser. How the math works Combinations count the ways to pick k items from n when order does not matter: n! ÷ (k! × (n − k)!). Permutations count them when order matters: n! ÷ (n − k)!. For two independent events, “A and B” multiplies the chances, and “A or B” adds them and takes away the overlap. The formula: C(n, k) = n! ÷ (k! × (n − k)!). Permutations (when order matters): P(n, k) = n! ÷ (n − k)!. n! means n × (n − 1) × … × 1.