What is the UTC Time Zone?

The UTC Time zone (abbreviation for Coordinated Universal Time) acts as a standard or centralized time zone for the world’s clocks. UTC is like a starting point by which to convert time across the world. It is the same time zone as GMT (Greenwich Mean Time). UTC is also referred to as Zero Meridian Time. The military calls the UTC time zone, Zulu Time, referring to the letter which represents it “Z” and the army’s call sign for it (Zulu).

UTC is one of the world’s 25 recognized, standard time zones. It’s a centralized point, used for time conversions. The other 24 time zones are either ahead or behind UTC time. Each one is “offset” from UTC by a certain number of hours, depending on where it is located. Learn more about time zones.

What is UTC Offset Time

You may have heard the term UTC Offset used in terms of time and date stamps. Or seen an offset, like UTC +3, or UTC -5. and wondered what this is.

It is an expression that tells you how many hours behind or ahead of Universal Coordinated Time the time is. For instance, 12:01 PM UTC +3, means the time is 3 hours ahead of UTC.

There are 12 time zones west of UTC, and 12 timezones east of UTC.  Time zones west of the UTC are considered “ahead” of Universal Time. As you move west from the UTC, each time zone has an incrementally larger offset number since it is one more hour ahead of UTC. That means you would simply add an hour to find the time in the UTC.

The “offset” time is always positive or negative, depending on which way you are moving; east or west. You can tell if a time is ahead of behind because it is expressed as – or +, or plus or minus, UTC.

For instance, the first time zone east of the UTC is 1 hour ahead. It’s expressed as UTC +1. Every time zone you encounter moving east from UTC will have a larger offset in increments of one hour. That is what the + and – or plus and minus numbers mean in time and data stamps.

Moving west from UTC, each timezone gets an increasing negative offset number, since each is one more hour “behind” UTC. The first zone west of UTC is UTC -1, the next one is UTC -2, and on.

Why Are There + and – Symbols Next to Time and Date Stamps

Time and Date Stamps have = and – (plus and minus) symbols to denote the zones offset from UTC. If the time zone is ahead of UTC (to the east) it will have a + (positive) sign. If it is to the west it will have a – (negative) sign.

The number itself represents the time zone and its hour offset from UTC. In other words, how many hours ahead or behind UTC it is.

You can use these + and – signs in date stamps to figure out the Universal Time for any time stamp that has them.


You can convert to UTC in military time as well. If the current time is 1400 UTC +4. Just do the math. Add 4 to 1400 and you get 1800. The time in UTC is 1800 hours.

About UTC Time Zone

The UTC was first introduced in 1960. It was given a formal name in 1967. A newer version was used starting in 1972 making use of added seconds called “leap seconds” to sync time with earth’s changing rotation speed. This made adjusting the time simpler and more efficient, along with more predictable.

The time zone is maintained by the ITU. Future versions seek to replace the use of the leap second.