Calculate the number of ways to choose r items from a set of n, where order doesn't matter.
How It Works
How Combination Calculator (nCr) Works
A combination counts how many distinct groups you can form by picking r items out of n total, without caring about the order you picked them in — computed as n! divided by r! times (n−r)!.
Worked Example
See It In Action
Choosing 2 people from a group of 5 (C(5,2)) gives 10 possible pairs, since the order you pick the two people in doesn't create a new pair.
FAQ
Frequently Asked Questions
What's the difference between this and a permutation?
Combinations ignore order (picking Alice then Bob is the same group as Bob then Alice), while permutations treat different orderings as distinct outcomes — use the permutation calculator when the sequence itself matters.
