Calculate the number of permutations (nPr) - how many ways to arrange r items from n when order matters.
Permutation Calculator
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What is a permutation?
A permutation is an arrangement where order matters. Arranging items A, B, C is different from C, B, A - they count as two separate permutations.
The formula is P(n,r) = n! / (n-r)!, also written as nPr.
For example, arranging 3 people from a group of 10 in order gives P(10,3) = 720 permutations. Compare to just 120 combinations when order does not matter.
Using the calculator
Enter the total items (n) and items to arrange (r). The calculator shows:
- Number of permutations with the formula breakdown
- Comparison with combinations - see how ignoring order reduces the count
- Related factorials for n! and r!
Switch modes to calculate combinations (order ignored) or factorials.
