Incrementing Months in Dates

Hiren has a series of dates in a worksheet. He would like to increment the month, so that (for instance) August becomes September in the dates. He wonders if there a way this can be done using Find and Replace.

You actually could use Find and Replace to do the changing. For instance, let's assume that the date shown in the cell range is 8/1/13 through 8/31/13. You could do a search for "8/" (without the quote marks) and replace it with "9/" (again, without the quotes).

There are a couple of problems with this approach, however. First, you'll end up making changes that you probably don't want to make. For instance, 8/18/13 is changed to 9/19/13 because there are two instances of 8/ in the original value. Second, when you change 8/31/13 to 9/31/13, Excel treats the converted date as text rather than as a date because 9/31 is not a valid date. In addition, you'll need to modify what you are searching for and replacing with based upon how the date is formatted in the cells.

A better solution is to use a formula to do the incrementing. If you have the Analysis ToolPak enabled in Excel, you can use the following formula:

=EDATE(A1,1)

The formula works great at incrementing the month. You need to understand how the formula works when the result of incrementing the month results in an invalid date. For instance, if the original date is 8/31/13 and you use the formula, it returns 9/30/13, the last valid day in September.

If you want, instead, to see an error when trying to increment, then the formula can be adjusted to compensate:

=IF(DAY(EDATE(A1,1))<DAY(A1),NA(),EDATE(A1,1))

This formula compares the date of the converted date to the day of the original date, and if they are not the same then it returns an #N/A error.

If you want, instead, to have the invalid date "fall over" to the next month (so that 8/31/13, when incremented, becomes 10/1/13), then you can use a different formula that doesn't rely on EDATE:

=DATE(YEAR(A1),MONTH(A1)+1,DAY(A1))

This formula will, interestingly enough, handle the "end of the year wrap" correctly. Thus, an original date in A1 of 12/1/13 will become 13/1/13 which is translated by Excel as 1/1/14.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (9263) applies to Microsoft Excel 97, 2000, 2002, and 2003. You can find a version of this tip for the ribbon interface of Excel (Excel 2007 and later) here: Incrementing Months in Dates.