UTC(Coordinated Universal Time)
Coordinated Universal Time (UTC) is the international reference for civil time, and the offset every other zone is measured against.
- UTC offset
- The reference offset for every other zone
- Abbreviation
- UTC
- Full name
- Coordinated Universal Time
- Military letter
- Zulu (Z)
- Regions
- Worldwide reference
- IANA zones
- UTC, Etc/UTC
- Converter model
- Fixed offset.
What UTC means
UTC is used for aviation, shipping, computing, scientific data and international coordination, and it is the offset the rest of this converter is defined against.
- UTC is maintained by the International Bureau of Weights and Measures from a worldwide ensemble of atomic clocks.
- UTC itself never shifts; only the local zones defined against it differ.
- In aviation and the military, UTC is spoken as Zulu time and written with a trailing Z.
Why this converter uses UTC as its base
Every zone in this converter is stored as a fixed number of minutes ahead of or behind UTC, so a conversion is simply the difference between two offsets. Anchoring on UTC keeps the arithmetic exact and reversible: converting a time from one zone to another and back always returns the original value, and no zone needs to know anything about any other zone.
It also matches how the rest of the world coordinates: aviation, shipping, computer systems and scientific data all record times in UTC, so a value converted here can be compared directly with those sources.
Cities on this offset
These cities keep UTC±00:00 as their standard offset:
- Accra
- Abidjan
- Reykjavík
- Dakar
Zones with the same offset
- GMT — Greenwich Mean Time (UTC±00:00)
History
UTC was introduced in the 1960s and given its present form in 1972, when the leap-second system tied it to International Atomic Time while keeping it close to the Earth's rotation.
Do not confuse with
- GMT — Greenwich Mean Time
- TAI — International Atomic Time