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: Converting UNIX Date/Time Stamps.

Converting UNIX Date/Time Stamps

by Allen Wyatt
(last updated October 22, 2015)

1

When you import information created by other computer programs, you may run into a situation where your data includes a date/time stamp created by UNIX. Once imported, you are then faced with the challenge of converting the date/time stamp to an Excel date/time format. Doing the conversion is rather easy, once you understand how both systems save their time.

Time stamps in UNIX are stored as an integer value representing the number of seconds since 1 January 1970. Further, time stamps are stored in GMT time, meaning there has been no adjustment to the stamp to reflect time zones or time-zone variations (such as Daylight Savings Time).

Excel, on the other hand, stores time stamps as a real number representing the number of days since 1 January 1900 (the default setting). The integer portion of the time stamp represents the number of full days, while the portion of the time stamp to the right of the decimal point represents the fractional portion of a day, which can be converted to hours, minutes, and seconds.

To do a straight conversion of a UNIX time stamp to the Excel system, all you need to do is use this formula:

=UnixTime / 86400 + 25569

In this example, UnixTime can be either a named cell containing the integer UNIX time stamp value, or it can be replaced with the actual integer value. Since the UNIX time stamp is stored as seconds, the division by 86400 is necessary to convert to days, which is used by Excel. (86400 is the number of seconds in a day.) You then add 25569, which is the number of days between 1 January 1900 and 1 January 1970. (It is the value returned if you use the =DATE(1970,1,1) function.)

Remember, that this does a straight conversion. You may still need to adjust for time zones. If the UNIX system recorded something occurring at 5:00 pm local time, you need to determine how many hours difference there is between you and GMT. If there happens to be four hours, then you need to adjust your conversion formula accordingly, as shown here:

=UnixTime / 86400 + 25569 - 4 / 24

If you are unsure of how your time zone relates to GMT, you can find the needed information here:

http://tycho.usno.navy.mil/zones.html

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (2051) 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: Converting UNIX Date/Time Stamps.

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

Changing Print Dialog Box Defaults

Some of the built-in defaults in Word can't be changed. Often times, however, you can work around these defaults by using ...

Discover More

Changing a Toolbar Button Image

Changing the image of a button on a Toolbar in Word.

Discover More

Cycling through Colors

If you need to easily change the font colors in a group of cells, one of the esoteric commands Excel provides is the Cycle ...

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)

Getting Rid of 8-Bit ASCII Characters

When working with data created outside of Excel, you may need to check that data to make sure it contains no unwanted ...

Discover More

Working with Imperial Linear Distances

Excel works with decimal values very easily. It is more difficult for the program to work with non-decimal values, such as ...

Discover More

Developing Reciprocal Conversion Formulas

When converting between measurement systems, you might want to use two cells for each type of measurement. Make a change in ...

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:

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. 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 one more than 2?

2013-09-17 03:14:47

Igor

This information helped me a lot. Thanks!



Regards, Igor from Ukraine (Kiev)


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.

Links and Sharing
Share