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 February 17, 2018)

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

Setting Your Default Document Directory

Word allows you to specify where it should start looking for your documents. This setting can come in handy if you store ...

Discover More

Understanding Outlining in Word

Remember when you needed to create outlines for your writing when you were in school? Word includes outlining ...

Discover More

Changing the Starting Page Number

Word normally numbers pages in a document starting at one and extending as far as the number of pages you have. If you ...

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)

Automatically Converting to GMT

You know what time it is, right? (Quick—look at your watch.) What if you want to know what time it is in Greenwich, ...

Discover More

Converting Phone Numbers

Sometimes you receive a phone number that contains alphabetic characters and you need to convert it to a purely numeric ...

Discover More

Converting to ASCII Text

When you work with imported or pasted data in an Excel worksheet, you may see some strange looking characters at 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 8 + 5?

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.