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.

Note:

If you would like to know how to use the macros described on this page (or on any other page on the ExcelTips sites), I've prepared a special page that includes helpful information. Click here to open that special page in a new browser tab.

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

Suppressing Zero Values in PivotTables

PivotTables are great for digesting and analyzing huge amounts of data. But what if you want part of that data excluded, ...

Discover More

Saving Versions

If you need to save your Excel data at different benchmarks, you might want to use some sort of "versioning" system. Such ...

Discover More

Generating a Count of Word Occurrences

Do you need to know the frequency with which certain words occur in your documents? There is no built-in way to derive ...

Discover More

Create Custom Apps with VBA! Discover how to extend the capabilities of Office 2013 (Word, Excel, PowerPoint, Outlook, and Access) with VBA programming, using it for writing macros, automating Office applications, and creating custom applications. Check out Mastering VBA for Office 2013 today!

More ExcelTips (menu)

Positioning a Column on the Screen

If you have static columns and dynamic columns on the screen, you may want the dynamic columns to always show a ...

Discover More

Sheets for Months

One common type of workbook used in offices is one that contains a single worksheet for each month of the year. If you ...

Discover More

Determining the Length of a String

Macros are great for working with strings, and one of the most commonly used string functions is Len. This tip explains ...

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 five minus 4?

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.