Permutation & Combination Calculator
Compute nPr, nCr, and factorials with formulas and explanations.
Results
Formulas:
nPr = n! / (n - r)!
nCr = n! / (r! × (n - r)!)
About the Permutation & Combination Calculator
What are Permutations and Combinations?
Permutations count the number of ways to arrange r items from a set of n, where order matters. Combinations count selections where order does not matter.
How to Use
Enter n and r, then click Calculate. The tool validates that r is not greater than n and both are non-negative, then shows nPr, nCr, and n!.
What is the difference between nPr and nCr?
nPr (permutation) considers order important. nCr (combination) considers only the group of items, not their order.
What are the constraints on n and r?
Both n and r must be non-negative integers, and r must be less than or equal to n.
Why does large n show scientific notation?
Factorials grow extremely fast. Very large results are displayed in scientific notation to remain readable.
Is this calculator free?
Yes, BestCalc's permutation and combination calculator is completely free with no ads or registration required.