End-of-Month Calculations

There are many ways you can use Excel to calculate the date at the end of the next month. One such way, using the EOMONTH function, is described in the previous tip. There are ways you can do it, however, without using that add-in function.

For instance, one approach is to AutoFill for the last days. (Sounds almost religious, doesn't it?) Let's say you wanted the last days of a series of months in the first column, beginning at A4. All you need to do is this:

1. In cell A4, enter the last day of the current month, such as 31 Mar 2009.
2. In cell A5, enter the last day of next month, such as 30 Apr 2009.
3. Select both cells, A4 and A5.
4. Click on the small square handle at the bottom right corner of the selection.
5. Drag the mouse downward as many cells as desired.

The result is that the area you drag over in step 5 is filled with end-of-month dates for the next however many months. Pretty cool! A slight variation on these steps could also be used:

1. In cell A4, enter the last day of the current month, such as 31 Mar 2009.
2. Select cell A4.
3. Right-click on the small square handle at the bottom right corner of the selection.
4. Drag the mouse downward as many cells as desired. When you release the mouse button, Excel displays a Context menu.
5. From the Context menu, choose Fill Months.

If you are not an AutoFill type of person, and instead prefer to use formulas, you could enter the starting end-of-month date in cell A4, and then the following formula in A5:

=DATE(YEAR(K32),MONTH(K32)+2,1)-1

This formula calculates the date for the first day of the month two months in the future, and then subtracts one from it. The result is the last day of the next month. The formula wraps around the end of years just fine, since the DATE function increments the years properly if the month value provided is greater than 12.

Another formulaic approach is to use the following:

=A4+32-DAY(A4+32)

This formula works because it adds 32 to the starting date (to make sure you are past the end of the following month), and then subtracts the number of days the result is past the end of the month.