GMT and BST — Greenwich Mean Time and British Summer Time
GMT (Greenwich Mean Time) means UTC+00:00 and BST (British Summer Time) means UTC+01:00: London keeps GMT in winter and BST in summer.
Current time in GMT
15:22:14
Greenwich Mean Time · UTC+00:00
Current time in BST
16:22:14
British Summer Time · UTC+01:00
About GMT and BST
GMT is the winter time of the United Kingdom. In summer the UK switches to British Summer Time (UTC+1).
Working with GMT and BST
Other labels for the same offsets: UTC for UTC+00:00, and CET and WAT for UTC+01:00. One hour to the east of GMT in this directory sits CET (UTC+01:00); no listed zone keeps the offset one hour to the west.
The letters BST are also used for Bangladesh Standard Time (UTC+06:00). Quote the IANA identifier, Europe/London, wherever the meaning has to be unambiguous.
Clock changes in GMT and BST
London follows the European rule: clocks go forward on the last Sunday in March and back on the last Sunday in October, at 01:00 UTC.
| Date | Change | New offset |
|---|---|---|
| March 28, 2027 | Clocks go forward one hour on Mar 28, 2027 at 01:00, moving from UTC+00:00 to UTC+01:00. | UTC+01:00 |
| October 31, 2027 | Clocks go back one hour on Oct 31, 2027 at 02:00, moving from UTC+01:00 to UTC+00:00. | UTC+00:00 |
Clock history of Europe/London
| Period | Clocks set to | Seasonal changes |
|---|---|---|
| since 1971 | UTC+00:00 | 55 years with a change, 1972–2026 |
| 1968–1971 | UTC+01:00 | none |
| 1947–1968 | UTC+00:00 | 20 years with a change, 1948–1967 |
| 1947 | UTC+01:00 | one, in 1947 |
| 1945–1947 | UTC+00:00 | one, in 1946 |
| 1940–1945 | UTC+01:00 | 5 years with a change, 1941–1945 |
| 1900–1940 | UTC+00:00 | 24 years with a change, 1916–1939 |
Who keeps UTC+00:00 and UTC+01:00
Moving between UTC+00:00 and UTC+01:00 through the year: London, Dublin, Manchester, Lisbon and Edinburgh.
Countries and territories whose clocks move between UTC+00:00 and UTC+01:00: Faroe Islands, Guernsey, Ireland, Isle of Man, Jersey, parts of Portugal, parts of Spain and the United Kingdom.
UTC+00:00
All year: Casablanca, Accra and Reykjavik.
Countries and territories that keep UTC+00:00 all year, from every entry in the tz database: Burkina Faso, Côte d’Ivoire, the Gambia, Ghana, parts of Greenland, Guinea, Guinea-Bissau, Iceland, Liberia, Mali, Mauritania, Morocco, São Tomé & Príncipe, Senegal, Sierra Leone, St. Helena, Togo and Western Sahara. Also on UTC+00:00 for part of the year: parts of Portugal. Where it is kept all year, UTC+00:00 also goes by these names in the tz database: Western European Standard Time.
UTC+01:00
All year: Lagos. Part of the year: Berlin, Madrid, Rome, Paris, Vienna, Warsaw, Budapest, Barcelona, Munich, Milan, Prague, Brussels, Stockholm, Amsterdam, Frankfurt, Oslo and 2 more until March 28, 2027 and from October 31, 2027.
Countries and territories that keep UTC+01:00 all year, from every entry in the tz database: Algeria, Angola, Benin, Cameroon, the Central African Republic, Chad, Congo - Brazzaville, parts of Congo - Kinshasa, Equatorial Guinea, Gabon, Niger, Nigeria and Tunisia. Also on UTC+01:00 for part of the year: Albania, Andorra, Austria, Belgium, Bosnia & Herzegovina, Croatia, Czechia, Denmark, France, Germany, Gibraltar, Hungary, Italy, Liechtenstein, Luxembourg, Malta, Monaco, Montenegro, the Netherlands, North Macedonia, Norway, Poland, San Marino, Serbia and 7 more. Where it is kept all year, UTC+01:00 also goes by these names in the tz database: Central European Standard Time and West Africa Time.
| City | Longitude | Solar noon on GMT / BST |
|---|---|---|
| Lagos | 3.38°E | 11:46 / 12:46 |
| London | 0.13°W | 12:01 / 13:01 |
| Berlin | 13.40°E | 11:06 / 12:06 |
| Casablanca | 7.59°W | 12:30 / 13:30 |
| Madrid | 3.70°W | 12:15 / 13:15 |
| Rome | 12.50°E | 11:10 / 12:10 |
| Accra | 0.19°W | 12:01 / 13:01 |
| Paris | 2.35°E | 11:51 / 12:51 |
| Vienna | 16.37°E | 10:55 / 11:55 |
| Warsaw | 21.01°E | 10:36 / 11:36 |
Which of GMT and BST applies today
Europe/London is on GMT (UTC+00:00) at the moment. On March 28, 2027, 145 days from the day this page was generated, its clocks move to BST (UTC+01:00).
A working day on GMT and BST
| Place | GMT’s 09:00–17:00 there | BST’s 09:00–17:00 there | Shared on GMT, over the next 12 months | Shared on BST, over the next 12 months |
|---|---|---|---|---|
| UTC | 09:00–17:00 | 08:00–16:00 | — | — |
| New York | 04:00–12:00 / 05:00–13:00 | 03:00–11:00 / 04:00–12:00 | 3 h to 4 h | 2 h to 3 h |
| London | 09:00–17:00 / 10:00–18:00 | 08:00–16:00 / 09:00–17:00 | 7 h to 8 h | 7 h to 8 h |
| Tokyo | 18:00–02:00 | 17:00–01:00 | none all year | none all year |
At 09:00 on a Monday on GMT time, Honolulu is still on Sunday. By 17:00 on a Friday on GMT time, Shanghai, Beijing, Shenzhen, Tokyo, Manila, Jakarta and 18 more have already reached Saturday.
For the working hours London shares with New York and Tokyo, and for its sunrise and sunset through the year, see the London page.
How GMT and BST compare with other zones
Right now GMT runs ahead of New York and Los Angeles and behind Berlin, Dubai, Kolkata, Singapore, Tokyo and Sydney. At the moment it shows the same time as UTC.
| Zone | UTC offset | Difference from GMT | Difference from BST | Against GMT, over the next 12 months |
|---|---|---|---|---|
| UTC | UTC+00:00 | Same time | 1h ahead | all year |
| New York | UTC-05:00 | 5h ahead | 6h ahead | 5h ahead / 4h ahead |
| Berlin | UTC+01:00 | 1h behind | Same time | 1h behind / 2h behind |
| Dubai | UTC+04:00 | 4h behind | 3h behind | all year |
| Kolkata | UTC+05:30 | 5h 30m behind | 4h 30m behind | all year |
| Singapore | UTC+08:00 | 8h behind | 7h behind | all year |
| Tokyo | UTC+09:00 | 9h behind | 8h behind | all year |
| Sydney | UTC+11:00 | 11h behind | 10h behind | 10h behind / 11h behind |
| Los Angeles | UTC-08:00 | 8h ahead | 9h ahead | 8h ahead / 7h ahead |
Cities using GMT and BST
GMT
BST
Convert GMT and BST to another zone
Related time zones
Time zone rules: IANA tz database release 2026c, applied when this page was generated on 2026-11-02.
Frequently asked questions
What are GMT and BST?
GMT is Greenwich Mean Time, UTC+00:00, and BST is British Summer Time, UTC+01:00. BST is the daylight saving time of the United Kingdom, used from late March to late October.
What is the IANA identifier for GMT and BST?
Europe/London, named after London. It has moved between UTC+00:00 and UTC+01:00 on the same yearly pattern since 1996.
When is it GMT and when is it BST in London?
Over the coming year London is on BST (UTC+01:00) from March 28, 2027 to October 31, 2027, and on GMT (UTC+00:00) until March 28, 2027 and from October 31, 2027. The labels themselves never move: GMT always means UTC+00:00 and BST always means UTC+01:00. Accra and Reykjavik keep GMT all year.
Is GMT the same as UTC?
As labels, both mean UTC+00:00. The places behind them, London and UTC, show the same time on 148 days of the coming year.