Permutation & Combination Calculator
Calculate nPr (permutations) and nCr (combinations) for any n and r.
Calculate permutations (nPr) and combinations (nCr) for any n and r, along with n factorial. Permutations count ordered arrangements; combinations count unordered selections. Enter the total number of items (n) and how many you choose (r) to get both, instantly.
It is a staple for probability, statistics and combinatorics homework.
Frequently asked questions
What is the difference between a permutation and a combination?
Permutations count arrangements where order matters (nPr); combinations count selections where order does not (nCr).
How do I calculate nCr?
nCr = n! ÷ (r! × (n−r)!). Enter n and r and the tool computes it for you.
When do I use permutations vs combinations?
Use permutations for ordered outcomes like race finishes or passwords; combinations for unordered groups like lottery picks or committees.
What is the maximum value of n?
The tool supports n up to 170, beyond which factorials exceed what standard numbers can represent.