UTC time now
00:00:00UTC
Thursday 1 October 2026
ISO 8601: 2026-10-01T00:00:00Z
In the UK it is 01:00 BST. UTC is 1 hour behind the UK right now. Your device: 01:00.
UTC (Coordinated Universal Time) is the world's time standard. It is kept by atomic clocks and steered to stay within 0.9 seconds of the Earth's rotation. Every time zone is an offset from UTC: the UK is UTC+0 in winter and UTC+1 in summer, and India is UTC+5:30 all year. UTC is also called Zulu time.
UTC and GMT
UTC and GMT show the same time. GMT began as mean solar time at Greenwich and is now the name of the UK's winter time zone. UTC is a scientific scale, calculated by the International Bureau of Weights and Measures (BIPM) near Paris from about 450 atomic clocks in national laboratories, including the National Physical Laboratory in Teddington. Use UTC in software, logs and international schedules, because it never changes for summer time.
Common UTC offsets
| Offset | Zone | Used in |
|---|---|---|
| UTC−5 / −4 | EST / EDT | New York, Toronto (standard / daylight time) |
| UTC−3 | — | São Paulo, Buenos Aires, Falkland Islands |
| UTC+0 | GMT, WET | UK and Ireland in winter, Iceland, Ghana |
| UTC+1 | BST, CET, WAT | UK in summer, Paris and Berlin in winter, Lagos |
| UTC+3 | MSK, TRT | Moscow, Istanbul, Nairobi |
| UTC+5:30 | IST | India |
| UTC+8 | CST, SGT, AWST | Beijing, Singapore, Perth |
| UTC+10 / +11 | AEST / AEDT | Sydney, Melbourne (standard / daylight time) |
The full list of abbreviations is on time zones explained.
Zulu time and ISO 8601
In aviation, shipping and the military, UTC is called Zulu time after the letter Z, which marks a zero offset. ISO 8601, the international standard for writing dates and times, uses the same letter: 2026-10-01T14:30:00Z is 14:30 UTC on 1 October 2026. The same moment in UK summer time is written 2026-10-01T15:30:00+01:00. Computers often store the moment as a count of seconds since 1 January 1970 UTC instead; convert one with the Unix timestamp converter.
Leap seconds
The Earth's rotation is slightly irregular, so since 1972 a leap second has been added to UTC 27 times to keep it close to solar time. The last one was added at the end of 31 December 2016, and UTC has been exactly 37 seconds behind International Atomic Time (TAI) since. The International Earth Rotation and Reference Systems Service has announced that there will be no leap second at the end of December 2026.
Leap seconds cause problems for computer networks, satellite navigation and financial systems. In November 2022 the General Conference on Weights and Measures (CGPM) decided that the maximum allowed difference between UTC and the Earth's rotation will be increased in or before 2035, so that UTC can run without leap seconds for at least a century.
Frequently asked questions
What is the difference between UTC and GMT?
They show the same time. UTC is the international standard kept by atomic clocks; GMT is the UK's winter time zone, which is set to UTC+0. In summer the UK switches to BST, which is UTC+1.
Is the UK on UTC?
In winter, yes: UK time equals UTC from the last Sunday in October to the last Sunday in March. During British Summer Time the UK is one hour ahead of UTC.
What is Zulu time?
Zulu time is UTC. Pilots, the military and weather services use the letter Z for the zero offset, so 1430Z means 14:30 UTC.
Does UTC change for daylight saving time?
No. UTC never changes. Countries change their offset from UTC instead: the UK moves from UTC+0 to UTC+1 for British Summer Time.
Will there be another leap second?
Not at the end of December 2026, according to the International Earth Rotation and Reference Systems Service. In 2022 the General Conference on Weights and Measures decided to widen the allowed gap between UTC and the Earth's rotation by 2035, which will stop leap seconds for at least a century.
See also British Summer Time and the time zone converter.