Math · NUMORA
Combinations Calculator
nCr and nPr.
Open interactive calculatorHow to use
Choose r from n: combinations ignore order, permutations keep it.
Formula
C = n! / (r!(n−r)!); P = n! / (n−r)!
FAQ
Is this Combinations calculator accurate?
The formula and assumptions are shown on the page, and the engine is covered by audit tests. Results are for reference — not financial or medical advice.
Do I need an account?
No. Calculations run in your browser. Recents can stay on this device.
What inputs do I need?
Choose r from n: combinations ignore order, permutations keep it.
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