Online Permutation and Combination Calculator

P counts ordered selections of r distinct elements from n; C counts the same selections without distinguishing order. For n=10 and r=3, P=720 and C=120. For n=0 and r=0, both are 1 because 0! = 1. When r=n, P=n! and C=1.

P(n,r) = n! / (n-r)!
C(n,r) = n! / (r! × (n-r)!)

Calculations use exact BigInt integers in this browser. Results show every decimal digit without grouping or scientific notation. Blank fields, noninteger values and values outside the stated range are rejected; r>n produces an error, not zero. This tool counts possibilities only: it does not list selections, allow replacement or repetition, calculate probabilities, or export a file.