Combination Calculator
Calculate the number of unordered ways (combinations) to choose r items from n.
Calculate
Enter your values below.
Result
nCr
0
Formula used
nCr = n! ÷ (r! × (n−r)!)
Example: 10C3 = 120.
How to use this calculator
- Enter n (total items), r (items chosen).
- Press Calculate to see your result instantly.
FAQ
Frequently asked questions
What is a combination?
A way of choosing items where order doesn't matter — e.g. picking a committee of 3 from 10 people.
Can r be greater than n?
No — r must be less than or equal to n.
How is this different from permutation?
Combination ignores order; permutation counts different orderings separately, so nCr is always ≤ nPr.
What is nC0?
Always 1 — there's exactly one way to choose nothing.