How to Count Combinations in Excel with COMBIN

COMBIN counts the ways to choose items when order doesn’t matter — lottery odds, menu options and quality-check sampling.

You will learn to

• Count possible lottery tickets
• Add combinations of different sizes
• Calculate a sampling probability from two COMBINs

How it works

COMBIN(number, number_chosen) counts how many groups of k items you can choose from n when order does not matter. =COMBIN(49,6) is 13,983,816, so one lottery ticket has a 1 in 13,983,816 chance of the jackpot. Use PERMUT instead when order matters.

Combinations are the basis of many probability calculations. The chance that a random sample of 4 from a lot of 20 contains none of the 3 defective units is =COMBIN(17,4)/COMBIN(20,4): the ways to pick only good units divided by all possible samples.

=COMBIN(B2,C2)