Time zone abbreviations
What EST, CET, IST and the rest stand for, their UTC offsets, and where the same letters mean different things.
| Abbreviation | Offset | Type | Used in (IANA zones) |
|---|---|---|---|
| ACDT | UTC+10:30 | daylight | Australia/Adelaide, Australia/Broken_Hill |
| ACST | UTC+9:30 | standard | Australia/Adelaide, Australia/Broken_Hill, Australia/Darwin |
| ACWST | UTC+8:45 | standard | Australia/Eucla |
| ADT | UTC−3 | daylight | America/Glace_Bay, America/Goose_Bay, America/Halifax, America/Moncton, America/Thule, Atlantic/Bermuda |
| AEDT | UTC+11 | daylight | Antarctica/Macquarie, Australia/Hobart, Australia/Melbourne, Australia/Sydney |
| AEST AEST time now | UTC+10 | standard | Antarctica/Macquarie, Australia/Brisbane, Australia/Hobart, Australia/Lindeman, Australia/Melbourne, Australia/Sydney |
| AKDT | UTC−8 | daylight | America/Anchorage, America/Juneau, America/Metlakatla, America/Nome, America/Sitka, America/Yakutat |
| AKST AKST time now | UTC−9 | standard | America/Anchorage, America/Juneau, America/Metlakatla, America/Nome, America/Sitka, America/Yakutat |
| AST | UTC−4 | standard | America/Anguilla, America/Antigua, America/Aruba, America/Barbados, America/Blanc-Sablon, America/Curacao +23 more |
| AWST | UTC+8 | standard | Antarctica/Casey, Australia/Perth |
| BST BST time now | UTC+1 | daylight | Europe/London |
| CAT | UTC+2 | standard | Africa/Blantyre, Africa/Bujumbura, Africa/Gaborone, Africa/Harare, Africa/Juba, Africa/Khartoum +5 more |
| CDT | UTC−5 | daylight | America/Chicago, America/Indiana/Knox, America/Indiana/Tell_City, America/Matamoros, America/Menominee, America/North_Dakota/Beulah +6 more |
| CEST | UTC+2 | daylight | Africa/Ceuta, Arctic/Longyearbyen, Europe/Amsterdam, Europe/Andorra, Europe/Belgrade, Europe/Berlin +27 more |
| CET CET time now | UTC+1 | standard | Africa/Algiers, Africa/Ceuta, Africa/Tunis, Arctic/Longyearbyen, Europe/Amsterdam, Europe/Andorra +29 more |
| CHADT | UTC+13:45 | daylight | Pacific/Chatham |
| CHAST | UTC+12:45 | standard | Pacific/Chatham |
| CST ambiguous CST time now | UTC−6 | standard | America/Bahia_Banderas, America/Belize, America/Chicago, America/Chihuahua, America/Costa_Rica, America/El_Salvador +19 more |
| CST ambiguous | UTC+8 | standard | China Standard Time (Asia/Shanghai) |
| EAT | UTC+3 | standard | Africa/Addis_Ababa, Africa/Asmera, Africa/Dar_es_Salaam, Africa/Djibouti, Africa/Kampala, Africa/Mogadishu +4 more |
| EDT | UTC−4 | daylight | America/Detroit, America/Grand_Turk, America/Indiana/Marengo, America/Indiana/Petersburg, America/Indiana/Vevay, America/Indiana/Vincennes +9 more |
| EEST | UTC+3 | daylight | Africa/Cairo, Asia/Beirut, Asia/Famagusta, Asia/Gaza, Asia/Hebron, Asia/Nicosia +10 more |
| EET EET time now | UTC+2 | standard | Africa/Cairo, Africa/Tripoli, Asia/Beirut, Asia/Famagusta, Asia/Gaza, Asia/Hebron +12 more |
| EST EST time now | UTC−5 | standard | America/Cancun, America/Cayman, America/Coral_Harbour, America/Detroit, America/Grand_Turk, America/Indiana/Marengo +14 more |
| GMT GMT time now | UTC±0 | standard | Africa/Abidjan, Africa/Accra, Africa/Bamako, Africa/Banjul, Africa/Bissau, Africa/Conakry +16 more |
| GST GST time now | UTC+4 | standard | Asia/Dubai, Asia/Muscat |
| HADT | UTC−9 | daylight | America/Adak |
| HAST | UTC−10 | standard | America/Adak |
| HKT HKT time now | UTC+8 | standard | Asia/Hong_Kong |
| HST HST time now | UTC−10 | standard | Pacific/Honolulu |
| IST ambiguous | UTC+1 | daylight | Europe/Dublin |
| IST ambiguous | UTC+2 | standard | Israel Standard Time (Asia/Jerusalem) |
| IST ambiguous IST time now | UTC+5:30 | standard | Asia/Calcutta, Asia/Colombo |
| JST JST time now | UTC+9 | standard | Japan Standard Time (Asia/Tokyo) |
| KST KST time now | UTC+9 | standard | Korea Standard Time (Asia/Seoul) |
| LHDT | UTC+11 | daylight | Australia/Lord_Howe |
| LHST | UTC+10:30 | standard | Australia/Lord_Howe |
| MDT | UTC−6 | daylight | America/Boise, America/Cambridge_Bay, America/Ciudad_Juarez, America/Denver, America/Edmonton, America/Inuvik |
| MSK MSK time now | UTC+3 | standard | Moscow Time (Europe/Moscow) |
| MST MST time now | UTC−7 | standard | America/Boise, America/Cambridge_Bay, America/Ciudad_Juarez, America/Creston, America/Dawson_Creek, America/Denver +4 more |
| MYT | UTC+8 | standard | Asia/Kuala_Lumpur, Asia/Kuching |
| NDT | UTC−2:30 | daylight | America/St_Johns |
| NST | UTC−3:30 | standard | America/St_Johns |
| NZDT | UTC+13 | daylight | Antarctica/McMurdo, Pacific/Auckland |
| NZST NZST time now | UTC+12 | standard | Antarctica/McMurdo, Pacific/Auckland |
| PDT | UTC−7 | daylight | America/Los_Angeles, America/Tijuana, America/Vancouver |
| PHT PHT time now | UTC+8 | standard | Philippine Time (Asia/Manila) |
| PKT PKT time now | UTC+5 | standard | Pakistan Standard Time (Asia/Karachi) |
| PMDT | UTC−2 | daylight | America/Miquelon |
| PMST | UTC−3 | standard | America/Miquelon |
| PST PST time now | UTC−8 | standard | America/Los_Angeles, America/Tijuana, America/Vancouver |
| SAST | UTC+2 | standard | Africa/Johannesburg, Africa/Maseru, Africa/Mbabane |
| SGT SGT time now | UTC+8 | standard | Asia/Singapore |
| WAT | UTC+1 | standard | Africa/Bangui, Africa/Brazzaville, Africa/Douala, Africa/Kinshasa, Africa/Lagos, Africa/Libreville +5 more |
| WEST | UTC+1 | daylight | Atlantic/Canary, Atlantic/Faeroe, Atlantic/Madeira, Europe/Lisbon |
| WET | UTC±0 | standard | Atlantic/Canary, Atlantic/Faeroe, Atlantic/Madeira, Europe/Lisbon |
| WIB | UTC+7 | standard | Western Indonesia Time (Asia/Jakarta) |
Built from the abbreviations the Unicode CLDR data prints for each IANA zone, plus common ones CLDR leaves out (CST for China, JST, KST, PKT, PHT, MSK, WIB).
Questions
Why are time zone abbreviations ambiguous?
They are not standardised. CST is used for US Central, China and Cuba; IST for India, Ireland and Israel; BST for British Summer Time and historically Bangladesh. When it matters, give a city or an IANA zone name instead.
Is EST the same as ET?
ET (Eastern Time) means whatever the US East Coast clocks show: EST (UTC−5) in winter, EDT (UTC−4) in summer. Strictly, EST is only the winter offset, but many people use it all year.
Why do some places show GMT+7 instead of an abbreviation?
Many zones have no widely used English abbreviation. The IANA database stopped inventing them in 2017, so software shows a numeric offset instead.