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

Updating Fields in Locked Forms

Updating form fields in Word can be confusing, especially when the fields are locked in a form. This tips explains why the ...

Discover More

Rotating a Drawing Object

You can add all sorts of drawing objects to a document. Once placed, you can then rotate them to your heart's content. This ...

Discover More

Using the GotoButton Field

Need to jump from one place in your document to another? One way to do this is through the user of the GotoButton field, ...

Discover More

Comprehensive VBA Guide Visual Basic for Applications (VBA) is the language used for writing macros in all Office programs. This complete guide shows both professionals and novices how to master VBA in order to customize the entire Office suite for their needs. Check out Mastering VBA for Office 2010 today!

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. There ...

Discover More

Rounding Time

Need to round the time in a cell to a certain value? There are a couple of ways you can do this with a formula.

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
##### Subscribe

FREE SERVICE: Get tips like this every week in ExcelTips, a free productivity newsletter. Enter your address and click "Subscribe."

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. Youâ€™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 3 - 0?

There are currently no comments for this tip. (Be the first to leave your commentâ€”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.