Permutation Calculator (nPr)
Count ordered arrangements of r items chosen from n.
Permutations count ordered arrangements — where the sequence of selection matters.
The math behind it
nPr = n! ÷ (n − r)! = n × (n − 1) × … × (n − r + 1).
Worked example
Top-3 finish from 10 runners → 10P3 = 10 × 9 × 8 = 720 orders.
FAQ
When do I use permutations?
When order matters — like rankings, passwords or seating arrangements.