Easy way to get the last day of the month in Excel

There are a lot of times I need to get the last day of a particular month.  One example I’ve used lately is trying to forecast sales for the remainder of a month using the average to date.  If it’s February 12, for instance, and the average daily sales so far are 12k.  I want to extrapolate that out for the rest of the month.  To do so, I need for Excel to know how many more days are remaining in the month- February.

Excel makes this very easy in one of two ways: Read more of this post