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

Displaying Fields

Fields (sometimes called field codes) allow you to insert dynamic information in your documents. If you want to see the codes ...

Discover More

Using Leaders with Tab Stops

Tab stops allow you to modify the horizontal position at which text is positioned on a line. Word allows you to preface the ...

Discover More

Displaying Nonprinting Characters

Nonprinting characters are a great boon when you are editing a document. Turn them on and you can easily see what characters ...

Discover More

Solve Real Business Problems Master business modeling and analysis techniques with Excel and transform data into bottom-line results. This hands-on, scenario-focused guide shows you how to use the latest Excel tools to integrate data from multiple tables. Check out Microsoft Excel 2013 Data Analysis and Business Modeling today!

MORE EXCELTIPS (MENU)

Finding and Deleting Links

A VBA macro to find and delete external links.

Discover More

Converting from Relative to Absolute

Addresses used in a formula can be either relative or absolute. If you need to switch between the two types of addressing, ...

Discover More

Converting Text Case

Ever notice that if someone types in all CAPS, it appears they are shouting? If your worksheets include lots of text, you may ...

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 for this tip:

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.

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.

Links and Sharing
Share