Determine the Number of Combinations for a Group of Items or Numbers – Combin() Function

The COMBIN() function will save you a lot of time when you want to find out how many groups or combinations of an item or number can be formed.

Now this may seem a bit confusing, so let’s use a real world example. Let’s say that you have six different colors of paper and you need to pair two different colored pieces of paper together. So, you have red, blue, green, orange, black, and brown colored paper and you need to end up with a pair such that, for instance, blue is with green. But, you want to figure out how many different unique combinations you could actually make.

Well, you can use a mathematical function to get this result, or, you can just use the COMBIN() function in Excel. In this example, to figure out the answer, you would enter this into a cell:

=COMBIN(6,2)

There are only two arguments for this function: number and number_chosen. The first argument is number, which is just the total number of items that you want to combine. The second argument is number_chosen, which is just how many items you want to be in each combination. So, the function above will calculate how many unique groups of 2 you can form from 6 unique items. The items can be anything: numbers, cars, paper, grass, or whatever you want.

Another, often used, example is that of forming unique teams or groups. So, say that you have 10 people and you want to find out how many different groups of 2 you can make with these ten people. This time, you just put a 10 in for the first argument and a 2 in for the second argument.

=COMBIN(10,2)

The result of this is that you can form 45 different groups of 2 from the total of 10 people.

The syntax for this function, along with its arguments listed, looks like this: