Everyday Calculators
Combinations Calculator (nCr)
Count how many ways r items can be chosen from n items when the order does not matter.
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Formula & Notes
- Combinations (order ignored)
C(n, r) = n! / (r! × (n − r)!)- Permutations (order matters)
P(n, r) = n! / (n − r)!
- Both n and r must be whole numbers, with 0 ≤ r ≤ n.
- C(n, r) always equals C(n, n − r), so choosing 3 of 10 has the same count as leaving 7 of 10.
- Results use exact big-integer arithmetic, so very large counts stay precise.
How to use it
- Enter Your Values Input your numbers or parameters into the Combinations Calculator (nCr). Fill in all required fields for an accurate calculation.
- Calculate Results Click the calculate button to process your inputs. The Combinations Calculator (nCr) delivers instant, accurate results.
- Review and Use Review your calculated results, explore the breakdown, and copy or share the output for your needs.
Tip Run the Combinations Calculator (nCr) multiple times with edge-case values to stress-test your assumptions before committing.
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