Permutation Calculator (nPr)
Calculate the number of permutations — the ways to arrange r items from a set of n items where order matters.
Enter values for n and r to calculate permutations.
Permutation Formula
P(n, r) = nPr = n! / (n − r)!
A permutation counts the number of ways to arrange r items chosen from n items where order matters. Choosing AB is different from BA.
Example: How many 3-letter arrangements from 10 letters?
P(10, 3) = 10! / 7! = 10 × 9 × 8 = 720
P(10, 3) = 10! / 7! = 10 × 9 × 8 = 720
When to Use Permutations
- Arranging people in a line
- Assigning places (1st, 2nd, 3rd) in a race
- Creating passwords where order matters
- Any selection where sequence is important
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Last updated: 2026-08-08