Math tool
Permutation & Combination Calculator
Enter n and r to get both nPr (permutations) and nCr (combinations).
—nPr (order matters)
—nCr (order doesn't matter)
Permutations vs combinations
A permutation counts arrangements where order matters — picking a 1st, 2nd, and 3rd place from 10 runners. A combination counts selections where order doesn't matter — picking any 3 runners for a team, regardless of order. nCr is always nPr divided by r!.