# A to Z of Excel Functions: the COMBIN Function

1 September 2017

*Welcome back to our regular A to Z of Excel Functions blog. Today we look at the COMBIN function.*

**The COMBIN function**

Are you often **COMBIN** the Excel functions to see how many subsets you can make? This function returns the number of combinations for a given number of items (*i.e.* the number of distinct subsets of items where order is unimportant). You should use **COMBIN** to determine the total possible number of groups for a given number of items.

The **COMBIN **function employs the following syntax to operate:

**COMBIN(number, number_chosen)**

The **COMBIN** function has the following arguments:

**number:**this is required and represents the number of items**number_chosen:**this is also required. This denotes the number of items in each combination.

It should be further noted that:

- numeric arguments are truncated to integers
- if either argument is nonnumeric,
**COMBIN**returns the*#VALUE!*error value - if
**number**< 0,**number_chosen**< 0, or**number**<**number_chosen**,**COMBIN**returns the*#NUM!*error value - a combination is any set or subset of items, regardless of their internal order. Combinations are distinct from permutations, for which the internal order is significant
- the number of combinations is as follows, where
**number**=**n**and**number_chosen**=**k**:

where:

and **n! **denotes **n **x **(n-1)** x … x 2 x 1.

Please see my example below:

*We’ll continue our A to Z of Excel Functions soon. Keep checking back – there’s a new blog post every other business day.*

*A full page of the function articles can be found here. *