Calculate the number of combinations (nCr) - how many ways to choose r items from n when order does not matter.
Combination Calculator
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What is a combination?
A combination is a selection where order does not matter. Choosing items A, B, C is the same combination as C, B, A.
The formula is C(n,r) = n! / (r! x (n-r)!), also written as "n choose r" or nCr.
For example, choosing 3 people from a group of 10 gives C(10,3) = 120 possible combinations.
Using the calculator
Enter the total items (n) and items to choose (r). The calculator shows:
- Number of combinations with the formula breakdown
- Comparison with permutations - see how order affects the count
- Related factorials for n! and r!
Switch modes to calculate permutations (order matters) or factorials.
