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: Dealing with Small Time Values.

Dealing with Small Time Values

by Allen Wyatt
(last updated August 17, 2015)

Zuzana has a need to perform calculations with very small time increments, such as thousandths of a second. She wonders how small of times Excel can deal with and how she can format for the display of the small increments.

Because of the way in which Excel stores times internally, it can theoretically deal with a time increment much smaller than a thousandth of a second. I say theoretically because there are a lot of factors that can negatively impact that precision.

As an example, consider that times and dates are stored in Excel such that full days are stored to the left of the decimal point and fractions of days are stored to the right. If you wanted to store a value as small as a hundred billionth of a second, you could conceivably do it. To store such a number in this format you end up with 1 day divided by 24 hours divided by 60 minutes divided by 60 seconds divided by 100,000,000,000. This results in a number that looks like this:

0.000000000000000115740740740741

Notice that there are a bunch of zeros followed by 15 significant digits. This is because Excel can only store a number that includes up to 15 significant digits. If you start doing anything else with this value, you ruin the value. For instance, you could add 3 to the value, signifying the addition of three days. Excel would then render this as the result:

3.000000000000000000000000000000

Notice that the small time increment disappeared. This happened because in the result of the addition, everything after the 3 became "significant," and Excel can only keep track of up to 15 significant digits, which was all zeros in the original number.

A thousandth of a second is a much longer duration than a hundred billionth of a second; it is represented in Excel's internal formatting as this:

0.0000000115740740740741

If you add three days to this value, you end up with this:

3.00000001157407

This is still accurate enough to render thousandths of a second just fine.

Of course, it doesn't do much good to store thousandths of a second internally if you can't display them in Excel. This is where custom formatting comes into play. You can create a custom format (as described in other issues of ExcelTips) that will display thousandths of a second just fine. Here's the format to use:

h:mm:s.000

If you try to use more zeros in the format (to display smaller increments of time), Excel will balk. The smallest increment you can display using custom formats is a thousandth of a second.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (9198) 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: Dealing with Small Time Values.

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

Continuing Your Numbering

If you have a couple of numbered lists separated by regular text paragraphs, you might want the secondary lists to be ...

Discover More

Finding Missing Fonts

When you open documents that were created a long time ago on a system far, far away (sounds almost epic, doesn't it?), ...

Discover More

Removing Specific Fields

Word allows you to place all sorts of fields in your documents. If you want to search for only specific types of fields, ...

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)

Rounding to the Nearest Quarter Hour

When entering times in a worksheet, you may have a need to round whatever you enter to the nearest 15-minute increment. ...

Discover More

Combining and Formatting Times

Excel allows you to store times in your worksheets. If you have your times stored in one column and an AM/PM indicator in ...

Discover More

Converting Time Notation to Decimal Notation

Want to convert an elapsed time, such as 8:37, to a decimal time, such as 8.62? If you know how Excel stores times ...

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 three more than 8?

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.