100% free · no signupRuns in your browser
Permutation Calculator
P(n, r) = n! / (n − r)! for ordered arrangements.
Best for: Use it for rankings, race finishes, passwords, seat orderings - anywhere order matters.
Input
How it's calculated & sources
The Permutation Calculator uses the standard, deterministic formula, so the same inputs always produce the same result. It runs entirely in your browser, so your inputs are never uploaded. Last reviewed June 2026.
Free & no sign-up · runs entirely in your browser. Results are estimates for general information, not professional advice — verify important decisions with a qualified expert. Last reviewed June 2026.
How it works
P(n, r) = n! / (n − r)! — number of ordered arrangements of r items from n.
Example
P(5, 2) = 5! / 3! = 20
Frequently asked questions
Permutation vs combination?+
Permutation cares about order (ABC ≠ CAB). Combination ignores order (ABC = CAB).
Continue your journey
Where people usually head next.
📏
Significant Figures Calculator
Count significant figures in a number and round to a chosen number of sig figs.
🎯
Percent Error Calculator
Measure how far a measured value is from the true value, as a percentage.
🔬
Scientific Notation Converter
Convert numbers between standard decimal form and scientific (and E) notation.
🧪
Scientific Calculator
Evaluate expressions with sin, cos, log, ln, sqrt, π and e.