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: Adjusting Times for Time Zones.

Adjusting Times for Time Zones

by Allen Wyatt
(last updated September 22, 2014)

David collects data from two locations, one on the East coast and the other on the West coast. After collecting the East coast times, he needs to adjust them for the time zone differences. He is wondering how to adjust the East coast times by three hours so they represent West coast times.

How to adjust an East coast time by three hours to be consistent with West coast times depends on the nature of the times you are adjusting. In general, if the data is stored as an Excel date/time serial number, then the adjustment is easy. All you have to do is remember that in the serial number format, anything to the left of the decimal point is days and anything to the right of the decimal point is partial days (hours, minutes, and seconds).

Since an hour is 1/24 of each day, three hours would be 3/24, or 0.125. Simply subtract this value from the serial value stored in the worksheet, and you've adjusted the time for the difference in time zones. The actual formula is easy:

=A1-0.125

You have to be a bit careful in doing this sort of adjustment with your date/time serial numbers, however. If the values in the worksheet are simply time values (there is no date component to the left of the decimal point), then subtracting 0.125 from the time value can result in an erroneous result if the original time is anywhere between midnight and 3:00 am. The way around that is to make the formula just a bit more complex:

=IF(A1<0.125,A1+0.875,A1-0.125)

If the value in A1 is strictly a time value, between midnight and 3:00 am, the formula adds 21 hours (21/24 or 0.875) to the value, providing the expected result of an adjusted time between 9:00 pm and midnight.

Another potential gottcha regards the actual time zones in which the East coast data is collected. If the data is collected from a single known location, it is no big deal—you can look at a map and figure out what time zones are in play. If the data is collected from all over the Eastern time zone, then the problem is determining whether the data should be adjusted by either two or three hours. You see, some areas in the Eastern time zone don't change to Daylight Savings Time uniformly, so it is possible that at some times of the year the adjustment to the time may be two hours and other times of the year it may be three.

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (3259) 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: Adjusting Times for Time Zones.

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

Too Many Cell Formats

The error message "too many cell formats" can be difficult to fix. This tip describes ways you can attempt to get rid of the ...

Discover More

Changing Text Case

Word provides a built-in shortcut to change the case of a text selection. Understanding how that shortcut works (and the ...

Discover More

Determining the Length of a String

Need to find out in a macro how long a particular text string is? You can figure it out by using the Len function, described ...

Discover More

Save Time and Supercharge Excel! Automate virtually any routine task and save yourself hours, days, maybe even weeks. Then, learn how to make Excel do things you thought were simply impossible! Mastering advanced Excel macros has never been easier. Check out Excel 2010 VBA and Macros today!

MORE EXCELTIPS (MENU)

Displaying a Result as Minutes and Seconds

When you use a formula to come up with a result that you want displayed as a time, it can be tricky figuring out how to get ...

Discover More

Calculating Elapsed Time with Excluded Periods

When using Excel to calculate elapsed time, there can be all sorts of criteria that affect the formulas you would otherwise ...

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
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