Time zone abbreviations
Abbreviations are unofficial and several of them mean more than one thing. This table gives the IANA identifier for each one we cover, both offsets, and a note wherever the abbreviation is genuinely ambiguous.
United States
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| EST | Eastern Time ⚠ ambiguous — see note below | America/New_York | UTC−5 | UTC−4 | — |
| PST | Pacific Time ⚠ ambiguous — see note below | America/Los_Angeles | UTC−8 | UTC−7 | — |
| CST | Central Time ⚠ ambiguous — see note below | America/Chicago | UTC−6 | UTC−5 | — |
| MST | Mountain Time ⚠ ambiguous — see note below | America/Denver | UTC−7 | UTC−6 | — |
| HST | Hawaii Time ⚠ ambiguous — see note below | Pacific/Honolulu | UTC−10 | — | — |
| AKST | Alaska Time | America/Anchorage | UTC−9 | UTC−8 | — |
Europe
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| GMT | Greenwich Mean Time ⚠ ambiguous — see note below | Europe/London | UTC+0 | UTC+1 | — |
| CET | Central European Time ⚠ ambiguous — see note below | Europe/Paris | UTC+1 | UTC+2 | — |
| BST | British Summer Time ⚠ ambiguous — see note below | Europe/London | UTC+0 | UTC+1 | — |
| EET | Eastern European Time ⚠ ambiguous — see note below | Europe/Athens | UTC+2 | UTC+3 | — |
| MSK | Moscow Time ⚠ ambiguous — see note below | Europe/Moscow | UTC+3 | — | — |
| WET | Western European Time ⚠ ambiguous — see note below | Europe/Lisbon | UTC+0 | UTC+1 | — |
| TRT | Türkiye Time ⚠ ambiguous — see note below | Europe/Istanbul | UTC+3 | — | — |
Global
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| UTC | Coordinated Universal Time ⚠ ambiguous — see note below | UTC | UTC+0 | — | — |
Asia
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| IST | India Standard Time ⚠ ambiguous — see note below | Asia/Kolkata | UTC+5:30 | — | — |
| JST | Japan Standard Time ⚠ ambiguous — see note below | Asia/Tokyo | UTC+9 | — | — |
| GST | Gulf Standard Time | Asia/Dubai | UTC+4 | — | — |
| SGT | Singapore Time | Asia/Singapore | UTC+8 | — | — |
Oceania
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| AEST | Australian Eastern Time ⚠ ambiguous — see note below | Australia/Sydney | UTC+11 | UTC+10 | — |
Canada
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| AST | Atlantic Time ⚠ ambiguous — see note below | America/Halifax | UTC−4 | UTC−3 | — |
| NST | Newfoundland Time ⚠ ambiguous — see note below | America/St_Johns | UTC−3:30 | UTC−2:30 | — |
South America
| Code | Name | IANA zone | Standard | Daylight | Now |
|---|---|---|---|---|---|
| BRT | Brasília Time ⚠ ambiguous — see note below | America/Sao_Paulo | UTC−3 | — | — |
Where the abbreviations collide
EST — Eastern Time
EST strictly means Eastern Standard Time (UTC−5). From mid-March to early November the same region runs on EDT (UTC−4). Most people searching for EST mean Eastern Time in general, which is what this page assumes.
GMT — Greenwich Mean Time
The UK uses GMT in winter and British Summer Time (BST, UTC+1) from late March to late October. GMT itself never shifts.
PST — Pacific Time
PST means Pacific Standard Time (UTC−8). In summer the same region runs on PDT (UTC−7).
CST — Central Time
CST is used for three different zones: Central Time in North America (UTC−6), China Standard Time (UTC+8) and Cuba Standard Time. This page covers the North American zone.
UTC — Coordinated Universal Time
UTC is the reference every other zone is measured against. It never observes daylight saving, which is why servers, aviation and finance use it.
CET — Central European Time
CET is UTC+1; the same countries use CEST (UTC+2) in summer. It covers most of western and central Europe, from Madrid to Warsaw.
IST — India Standard Time
IST is genuinely ambiguous: India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2) all share the abbreviation. This page covers India, which accounts for most searches.
MST — Mountain Time
Most of the Mountain zone switches to MDT in summer, but Arizona stays on MST all year — which is why Phoenix and Denver are sometimes an hour apart and sometimes not.
BST — British Summer Time
BST also stands for Bangladesh Standard Time (UTC+6). This page covers British Summer Time.
EET — Eastern European Time
EET is UTC+2, moving to EEST (UTC+3) in summer. Greece, Finland, Romania and the Baltic states use it.
JST — Japan Standard Time
Japan has no daylight saving, so JST is UTC+9 all year.
AEST — Australian Eastern Time
New South Wales, Victoria and Tasmania move to AEDT (UTC+11) in the southern summer, while Queensland stays on AEST all year.
HST — Hawaii Time
Hawaii does not observe daylight saving, so the offset is UTC−10 all year and the gap to the mainland changes twice a year.
MSK — Moscow Time
Russia abolished seasonal clock changes in 2014, so Moscow stays on UTC+3 all year.
AST — Atlantic Time
AST can also mean Arabia Standard Time (UTC+3). This page covers Atlantic Time in eastern Canada.
WET — Western European Time
Portugal and Ireland share the UK offset in practice, though Ireland labels its summer time differently.
BRT — Brasília Time
Brazil stopped observing daylight saving in 2019, so the offset is UTC−3 year-round.
TRT — Türkiye Time
Türkiye fixed its clocks to UTC+3 permanently in 2016 and no longer changes them.
NST — Newfoundland Time
Newfoundland runs at UTC−3:30, one of the few half-hour offsets outside Asia.
For anything that matters, use the IANA identifier instead. It names exactly one set of rules and carries the full history of that region's clock changes.
Converting between two of these?
Every popular pair has its own page with both seasonal answers.
Browse conversions