Time zones explained
The UK is on BST now
UK time: 01:00:00 · UTC: 00:00:00
UTC is 1 hour behind the UK right now. Your device is set to Europe/London.
A time zone is an area that keeps the same clock time, written as an offset from UTC. The UK time zone is GMT (UTC+0) in winter and BST (UTC+1) in summer; its database name is Europe/London. Offsets in use run from UTC−12 to UTC+14, and some are half an hour or 45 minutes off the hour.
How time zones work
The Earth turns 15 degrees an hour, so in theory each one-hour zone is 15 degrees of longitude wide, centred on the Greenwich meridian. In practice governments set their own zones. China uses one zone across about 60 degrees of longitude; India uses UTC+5:30 and Nepal UTC+5:45. Many countries also move their clocks for summer, on dates of their own choosing, so the gap between two places can change during the year.
Every zone is measured from UTC, the atomic time standard. Software uses names from the IANA time zone database, such as America/New_York, because a name records a region's full history of offsets and clock changes, which an abbreviation cannot.
Time zone abbreviations
| Abbreviation | Name | Offset | Used in | Summer time |
|---|---|---|---|---|
| UTC | Coordinated Universal Time | +0 | World standard | Never changes |
| GMT | Greenwich Mean Time | +0 | UK and Ireland in winter, Iceland, Ghana | UK moves to BST |
| BST | British Summer Time | +1 | UK in summer | This is summer time |
| IST | Irish Standard Time | +1 | Ireland in summer | This is summer time |
| WET | Western European Time | +0 | Portugal, Canary Islands | WEST in summer |
| WEST | Western European Summer Time | +1 | Portugal, Canary Islands | This is summer time |
| WAT | West Africa Time | +1 | Nigeria, Cameroon, Angola | None |
| CET | Central European Time | +1 | France, Germany, Spain, Poland, Gibraltar | CEST in summer |
| CEST | Central European Summer Time | +2 | Same as CET | This is summer time |
| SAST | South Africa Standard Time | +2 | South Africa | None |
| EET | Eastern European Time | +2 | Greece, Finland, Romania, Ukraine | EEST in summer |
| EEST | Eastern European Summer Time | +3 | Same as EET | This is summer time |
| MSK | Moscow Time | +3 | Moscow, western Russia | None |
| GST | Gulf Standard Time | +4 | UAE, Oman | None |
| PKT | Pakistan Standard Time | +5 | Pakistan | None |
| IST | India Standard Time | +5:30 | India | None |
| ICT | Indochina Time | +7 | Thailand, Vietnam, Cambodia, Laos | None |
| CST | China Standard Time | +8 | China | None |
| SGT | Singapore Time | +8 | Singapore | None |
| AWST | Australian Western Standard Time | +8 | Perth | None |
| JST | Japan Standard Time | +9 | Japan | None |
| ACST | Australian Central Standard Time | +9:30 | Darwin, Adelaide | Adelaide only: ACDT (+10:30) |
| AEST | Australian Eastern Standard Time | +10 | Brisbane, Sydney, Melbourne | AEDT, except Queensland |
| AEDT | Australian Eastern Daylight Time | +11 | Sydney, Melbourne, Hobart | This is summer time |
| NZDT | New Zealand Daylight Time | +13 | New Zealand | NZST (+12) in winter |
| AST | Atlantic Standard Time | −4 | Halifax, Bermuda, Puerto Rico | ADT (−3), not Puerto Rico |
| EST | Eastern Standard Time | −5 | New York, Toronto, Cayman Islands | EDT (−4), not Cayman |
| CST | Central Standard Time | −6 | Chicago, Dallas, Mexico City | CDT (−5), not Mexico City |
| MST | Mountain Standard Time | −7 | Denver, Arizona | MDT (−6), not Arizona |
| PST | Pacific Standard Time | −8 | Los Angeles, Vancouver | PDT (−7) |
Why abbreviations can mislead
The same letters often mean different zones. IST is India Standard Time (UTC+5:30) and Irish Standard Time (UTC+1). CST is US Central Standard Time (UTC−6) and China Standard Time (UTC+8). BST is British Summer Time, but also Bangladesh Standard Time (UTC+6). People also say "EST" all year when New York is on EDT. When it matters, give the city or the UTC offset, or send a link from the time zone converter.
UK overseas territories and Crown dependencies
| Place | Time zone | Clock changes |
|---|---|---|
| Jersey, Guernsey, Isle of Man | GMT / BST, same as UK | Same days as the UK |
| Gibraltar | CET (UTC+1) / CEST (UTC+2) | Same days as the UK |
| Bermuda | AST (UTC−4) / ADT (UTC−3) | US dates |
| Turks and Caicos Islands | EST (UTC−5) / EDT (UTC−4) | US dates |
| Cayman Islands | EST (UTC−5) | None |
| Anguilla, Montserrat, British Virgin Islands | AST (UTC−4) | None |
| Falkland Islands | UTC−3 | None since 2010 |
| South Georgia and the South Sandwich Islands | UTC−2 | None |
| St Helena, Ascension and Tristan da Cunha | GMT (UTC+0) | None |
| Pitcairn Islands | UTC−8 | None |
Zones and dates are from the IANA time zone database, which your browser uses for every clock on this site.
Time in other countries
Each page has a live clock, the time difference with the UK through the year and good times to call. The world clock shows them all at once.
- New York
- Chicago
- Los Angeles
- Toronto
- France
- Spain
- Germany
- Poland
- Turkey
- Nigeria
- South Africa
- Dubai
- Pakistan
- India
- Thailand
- China
- Hong Kong
- Singapore
- Philippines
- Tokyo
- Australia
- Perth
- Sydney
- Melbourne
- New Zealand
Frequently asked questions
What time zone is the UK in?
The UK uses Greenwich Mean Time (UTC+0) in winter and British Summer Time (UTC+1) from the last Sunday in March to the last Sunday in October. In software it is the IANA zone Europe/London.
How many time zones are there?
There is no single answer. In theory there are 24 one-hour zones, but countries choose their own offsets, including half-hour and 45-minute ones, and these run from UTC-12 to UTC+14. The IANA time zone database, used by phones and computers, has hundreds of named zones because it also records each region's history of clock changes.
Does Gibraltar use UK time?
No. Gibraltar uses Central European Time, one hour ahead of the UK all year, and changes its clocks on the same days.
Are Jersey, Guernsey and the Isle of Man on UK time?
Yes. All three Crown dependencies keep the same time as the UK, including British Summer Time.
Do all countries change their clocks?
No. Most countries in Asia and Africa, and some places in the Americas such as Arizona, keep the same time all year. The UK, the EU, most of the US and Canada, and south-east Australia change their clocks, but on different dates.
Related: British Summer Time and the meeting planner.