Updated
Using Permutation combination calculator
Combinations count selections without order: n! ÷ (r!(n − r)!). Permutations count ordered selections: n! ÷ (n − r)!.
Items must be distinct and selections are without replacement. Repeated objects and replacement draws need different formulas. Integer results are exact.
A worked example
With available items (n) = 5, items chosen (r) = 2, the combinations is 10.
Before you use the result
Items must be distinct and selections are without replacement. Repeated objects and replacement draws need different formulas. Integer results are exact.
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ToolOctopus. “Permutation combination calculator.” Updated 2026-09-26. https://tooloctopus.com/permutation-combination-calculator.
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