What is GMT?
GMT stands for Greenwich Mean Time. Its offset from UTC is UTC+0, the same clock time as UTC.
GMT is the time at the 0 degree meridian through Greenwich in London. It is the same clock time as UTC.
The United Kingdom and Ireland use GMT only in winter. In summer they move one hour ahead (BST in the UK). Iceland and several West African countries stay on GMT all year.
Where GMT is used
United Kingdom in winter, West Africa, Iceland. The table shows examples, not every place. Entries in bold are on GMT at that moment.
| Place | Mid-January 2026 | Mid-July 2026 | Now |
|---|---|---|---|
| London | GMT (UTC+0) | BST (UTC+1) | GMT (UTC+0) |
| Dublin | GMT (UTC+0) | IST (UTC+1) | GMT (UTC+0) |
| Reykjavik | GMT (UTC+0) | GMT (UTC+0) | GMT (UTC+0) |
| Accra | GMT (UTC+0) | GMT (UTC+0) | GMT (UTC+0) |
| Abidjan | GMT (UTC+0) | GMT (UTC+0) | GMT (UTC+0) |
| Dakar | GMT (UTC+0) | GMT (UTC+0) | GMT (UTC+0) |
See BST, the matching summer time.
Time difference between GMT and other cities
| City | Compared with GMT, now | Changes in the next 12 months |
|---|---|---|
| New York City | 5 hours behind | Sun 14 Mar 2027, 07:00 UTC: 4 hours behind |
| Los Angeles | 8 hours behind | Sun 14 Mar 2027, 10:00 UTC: 7 hours behind |
| London | Same time | Sun 28 Mar 2027, 01:00 UTC: 1 hour ahead Sun 31 Oct 2027, 01:00 UTC: Same time |
| Dubai | 4 hours ahead | No change |
| Mumbai | 5 hours 30 minutes ahead | No change |
| Singapore | 8 hours ahead | No change |
| Tokyo | 9 hours ahead | No change |
| Sydney | 11 hours ahead | Sat 3 Apr 2027, 16:00 UTC: 10 hours ahead Sat 2 Oct 2027, 16:00 UTC: 11 hours ahead |
A gap changes when the two places change their clocks on different dates. Dates are in UTC.
Working hours that overlap with GMT
When it is 09:00 to 17:00 in GMT, where is it also a working day (09:00 to 17:00)? This uses today’s clock settings, so check the meeting planner for weeks when clocks change.
| City | Shared working hours |
|---|---|
| New York City | 14:00 to 17:00 in GMT (09:00 to 12:00 in New York City) |
| Los Angeles | No shared working hours |
| London | 09:00 to 17:00 in GMT (09:00 to 17:00 in London) |
| Dubai | 09:00 to 13:00 in GMT (13:00 to 17:00 in Dubai) |
| Mumbai | 09:00 to 11:30 in GMT (14:30 to 17:00 in Mumbai) |
| Singapore | No shared working hours |
| Tokyo | No shared working hours |
| Sydney | No shared working hours |
Plan a meeting across several cities