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Permutation vs Combination

Permutation vs combination compared — whether order matters, formulas and examples, with a free combinatorics calculator.

A permutation counts arrangements where order matters; a combination counts selections where it does not. The only difference is whether ABC and ACB count as the same.

Permutation vs Combination at a glance

Permutation Combination
Order matters? Yes No
Formula nPr = n! / (n−r)! nCr = n! / (r!(n−r)!)
Example Race finishing order Picking a committee

When to use Permutation

Use a permutation when arrangement matters — rankings, passwords, sequences.

When to use Combination

Use a combination when only the group matters, not its order — lottery draws, teams.

Tools for Permutation & Combination

Permutation vs Combination

How do I know whether to use a permutation or combination?

Ask whether order matters. If rearranging the same items counts as a different outcome (a ranking, a sequence), use a permutation. If not (a group, a selection), use a combination.