Converting UTC Times to Local Times

Brian lives in Australia and needs to convert a UTC time into his local time. Problem is, he doesn't know how to go about doing it.

UTC is an abbreviation for Coordinated Universal Time. (Yes, I know it looks like the abbreviation letters are out of order. They are; this is why it isn't an acronym. The abbreviation is—believe it or not—based on a political compromise.) UTC is equivalent to International Atomic Time with leap seconds added at irregular intervals to compensate for the Earth's slowing rotation. UTC is never out of synch with GMT (Greenwich Meridian Time) by more than nine tenths of a second, so the two (UTC and GMT) are virtually equivalent in common usage.

Because of this, all you need to do to convert from UTC to a local time is to figure out how many hours your time varies from GMT. There are any number of Websites you can visit to determine such information; the following is an example of one you can use. (Just click a city near you that you know is on the same time zone as you, then look at the resulting time to see how many hours different you are from GMT.)

http://www.timeanddate.com/worldclock/

If you are near Sydney, Australia, you can see that your local time is ten hours ahead of GMT. This means that to determine the local time if you know UTC, all you need to do is add ten hours to that time. If the UTC is in cell B3 in Excel's date and time format, then you could use either of these formulas:

=B3 + TIME(10,0,0)
=B3 + (10 / 24)

You should understand that these formulas don't account of Daylight Savings Time. If you live in an area that implements some sort of time adjustment scheme (such as DST), then you will need to adjust your formulas accordingly. This means that if you are near Sydney you need to figure out when DST starts and ends, and if you are currently affected by DST you will need to add eleven hours to your UTC value.

You can find more information about adjusting local times to GMT (or, if you will, UTC) by visiting this tip:

http://excel.tips.net/T002185

ExcelTips is your source for cost-effective Microsoft Excel training. This tip (3440) 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 UTC Times to Local Times.