Combination Calculator

Find how many ways to choose r items from n when order does not matter.

Modify the values and click the Calculate button to use this tool.

Combination Calculator

Enter n and r. Combinations ignore order — {A,B} equals {B,A}.

Formula

C(n,r) = n! / (r! × (n−r)!)

Combination formula

C(n,r) = n! / (r! × (n−r)!)

Example: C(10,3) = 120 ways to choose 3 from 10.