Please Note: This article is written for users of the following Microsoft Excel versions: 97, 2000, 2002, and 2003. If you are using a later version (Excel 2007 or later), this tip may not work for you. For a version of this tip written specifically for later versions of Excel, click here: Determining Differences Between Dates.

Determining Differences Between Dates

by Allen Wyatt
(last updated December 22, 2014)

When you are programming Excel macros, you should know that dates are stored internally, within variables, as serial numbers. The serial number represents the number of days elapsed since a starting "base date," specifically since 1 January 100. This means that you can perform math with the serial numbers, if desired. You can, for instance, find the number of days between two dates by simply subtracting the dates from each other.

Note that the starting date above is not a typo; in macros the calculations are from a much earlier base date than they are in a worksheet. (Worksheets use either 1900 or 1904 as their base date, depending on how you've configured Excel.) This means that macros can work with a much wider range of dates than can be done in worksheets.

If you want to get fancier in your date calculations, you can use the DateDiff function. This function allows you, for instance, to determine the number of weeks or months between two dates. In order to use the function to find this type of information, you would do as follows:

iNumWeeks = DateDiff("ww", dFirstDate, dSecondDate)
iNumMonths = DateDiff("m", dFirstDate, dSecondDate)

The first line determines the number of weeks between the two dates, and the second determines the number of months between them.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (2535) 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: Determining Differences Between Dates.

Author Bio

Allen Wyatt

With more than 50 non-fiction books and numerous magazine articles to his credit, Allen Wyatt is an internationally recognized author. He  is president of Sharon Parq Associates, a computer and publishing services company. ...

MORE FROM ALLEN

Pulling All Fridays

It can be handy to know when specific weekdays occur within a range of dates. Figuring out this information, using formulas, ...

Discover More

Recovered Document becomes Default

Word has a feature called AutoRecover that helps you when Word or Windows crashes. If your Normal template gets messed up for ...

Discover More

Jumping to the Start or End of a Document

When creating macros, it is often necessary to move the insertion point around the document so that text can be processed in ...

Discover More

Excel Smarts for Beginners! Featuring the friendly and trusted For Dummies style, this popular guide shows beginners how to get up and running with Excel while also helping more experienced users get comfortable with the newest features. Check out Excel 2013 For Dummies today!

More ExcelTips (menu)

Skipping Hidden Rows in a Macro

As your macro processes information in a worksheet, you may want to make sure that it skips over rows that are hidden. The ...

Discover More

Finding and Deleting Links

A VBA macro to find and delete external links.

Discover More

Forcing Manual Calculation For a Workbook

If you have a large, complex workbook, you may want to make sure that it is always calculated manually instead of ...

Discover More
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

View most recent newsletter.

Comments

If you would like to add an image to your comment (not an avatar, but an image to help in making the point of your comment), include the characters [{fig}] in your comment text. You’ll be prompted to upload your image when you submit the comment. Maximum image size is 6Mpixels. Images larger than 600px wide or 1000px tall will be reduced. Up to three images may be included in a comment. All images are subject to review. Commenting privileges may be curtailed if inappropriate images are posted.

What is 7 - 0?

There are currently no comments for this tip. (Be the first to leave your comment—just use the simple form above!)


This Site

Got a version of Excel that uses the menu interface (Excel 97, Excel 2000, Excel 2002, or Excel 2003)? This site is for you! If you use a later version of Excel, visit our ExcelTips site focusing on the ribbon interface.

Newest Tips
Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

(Your e-mail address is not shared with anyone, ever.)

View the most recent newsletter.