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Combination Calculator
C(n, r) = n! / (r!(n − r)!) for unordered selections.
Best for: Use it for lottery odds, committees, hands of cards, or any selection where order is irrelevant.
Input
How it's calculated & sources
The Combination 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
C(n, r) = n! / (r!(n − r)!) — unordered selections.
Example
C(5, 2) = 10
Frequently asked questions
Where is this used?+
Lottery odds, poker hands, committee selection — anywhere order doesn't matter.
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