UTC Time Now (Live Clock)
Local Time to UTC • UTC to Local Time
About UTC
Coordinated Universal Time (UTC) is the primary time standard by which the world regulates clocks and time. It is the global reference time used for synchronizing clocks across different time zones.
UTC is based on the precision of atomic clocks, which makes it highly accurate compared to other time standards like Greenwich Mean Time (GMT). While GMT relies on the Earth’s rotation, UTC is based on atomic time, ensuring consistency and precision.
UTC is more precise and consistent because it is calculated using highly accurate atomic clocks, which are occasionally adjusted with leap seconds to account for the Earth’s irregular rotation. Global Positioning Systems (GPS) use UTC to provide accurate time information.
An atomic clock measures time based on the vibrations or oscillations of atoms, usually cesium-133. A second is defined as 9,192,631,770 cycles of the radiation that corresponds to the transition between two energy levels of the cesium-133 atom. Atomic clocks can be a single clock or part of an ensemble of clocks working together to improve accuracy.
UTC does not observe daylight saving time (DST). It remains constant throughout the year, unaffected by DST changes. Daylight saving time typically adds 1 hour to the local standard time. Regions may adjust their local time relative to UTC when they observe DST. The UK uses GMT during the winter months and switches to British Summer Time (BST, UTC+1) during DST.
The earth is divided into 24 time zones, -11 to +12. Each time zone is 1 hour long, or 15° wide in longitude.
In practical use, UTC is often denoted with a “Z” at the end, derived from “Zulu” time in aviation and military contexts. For example, 14:30 UTC is written as 14:30Z. (What is Zulu time?)
UTC Time Representation
ISO 8601 is an international standard for representing dates and times in a clear, consistent format, widely used in data exchange and communication systems. When using ISO 8601, UTC time is represented in a specific way to avoid ambiguity.
The standard format for UTC combines the date and time as follows:
YYYY-MM-DDTHH:MM:SSZ
- YYYY – 4-digit year
- MM – 2-digit month (01 to 12)
- DD – 2-digit day of the month (01 to 31)
- T – Indicates the start of the time component
- HH – 2-digit hour (00 to 23)
- MM – 2-digit minute (00 to 59)
- SS – 2-digit second (00 to 59, with optional fractions for milliseconds)
- Z – Indicates that the time is in UTC
Note: Z stands for “Zulu” time, a common military and aviation term for UTC.
Example: 2024-11-20T14:30:00Z represents 14:30:00 (2:30 PM) UTC on November 20, 2024.