What Is UTC? Coordinated Universal Time Explained
UTC stands for Coordinated Universal Time and is the standard against which every clock in the world is set.
What it is
UTC is a time scale based on atomic clocks, kept close to the Earth's rotation by occasional leap seconds. Time zones are written as offsets from it: the UK in winter is UTC+0 and in summer UTC+1, New York is UTC-5 or UTC-4, and India is UTC+5:30.
Why UTC and not CUT
The abbreviation was chosen as a compromise between the English order, CUT, and the French order, TUC, so it matches neither language exactly. UTC has no daylight saving, which is why computers, aircraft and servers prefer it.
Frequently asked questions
Is UTC the same as GMT?
In everyday use they show the same time. GMT is a time zone, while UTC is the atomic time standard.
Clock change guides
- What Is Daylight Saving Time (DST)? A Plain-English GuideWhat daylight saving time is, how it works in the UK, Europe and the US, why it exists, its history, who uses it and the argument over scrapping it.
- Why Do the Clocks Go Back in October? The Real ReasonThe clocks go back in autumn to return the UK to GMT, so winter mornings are lighter. The history, the rule, what time it happens and what changes for you.
- When Do the Clocks Go Forward Again After Going Back?When the UK clocks go forward again after the autumn change, how long the UK stays on GMT, when evenings get lighter and how to remember to reset your clocks.