Combinatorics

Permutation/Combination/Factorial Calculator

n (total items)

r (selection count)

Combinatorics Calculator Guide

Functions

Permutation P(n,r): Number of ways to select r items from n in order = n!/(n-r)!
Combination C(n,r): Number of ways to select r items from n without order = n!/(r!(n-r)!)
Factorial n!: n factorial
Multiset Permutation: Permutations with repeated elements

Tips

n and r must be non-negative integers, and r ≤ n
Maximum n is 170 (overflow beyond that)
Multiset input format: repeat count for each element, comma separated
All calculations done locally in the browser