Overview
This comprehensive reference lists all major timezone abbreviations used worldwide, including their UTC offsets, daylight saving time (DST) rules, and common usage regions. Use this guide to quickly lookup timezone information when working with timestamps and scheduling.
Quick Lookup
Most Common Timezones
| Abbreviation | Full Name | UTC Offset (Standard) | DST Offset | Regions |
|---|---|---|---|---|
| UTC | Coordinated Universal Time | +00:00 | No DST | Worldwide Standard |
| GMT | Greenwich Mean Time | +00:00 | No DST | UK, West Africa |
| EST | Eastern Standard Time | -05:00 | EDT -04:00 | US East Coast |
| PST | Pacific Standard Time | -08:00 | PDT -07:00 | US West Coast |
| CST | Central Standard Time | -06:00 | CDT -05:00 | US Central |
| MST | Mountain Standard Time | -07:00 | MDT -06:00 | US Mountain |
| CET | Central European Time | +01:00 | CEST +02:00 | Central Europe |
| IST | India Standard Time | +05:30 | No DST | India |
| JST | Japan Standard Time | +09:00 | No DST | Japan |
| AEST | Australian Eastern Standard | +10:00 | AEDT +11:00 | Eastern Australia |
By UTC Offset
UTC -12:00 to -09:00
UTC -12:00
- BIT - Baker Island Time
- Region: Baker Island, Howland Island
- DST: No DST
- Notes: Uninhabited territories
UTC -11:00
- NUT - Niue Time
- Region: Niue
- DST: No DST
- SST - Samoa Standard Time
- Region: American Samoa
- DST: No DST
UTC -10:00
- HST - Hawaii-Aleutian Standard Time
- Region: Hawaii (most)
- DST: No DST
- Notes: Most of Hawaii doesn't observe DST
- HAST - Hawaii-Aleutian Standard Time
- Region: Aleutian Islands
- DST: HADT -09:00
- TAHT - Tahiti Time
- Region: French Polynesia
- DST: No DST
UTC -09:00
- AKST - Alaska Standard Time
- Region: Alaska
- DST: AKDT -08:00
- HADT - Hawaii-Aleutian Daylight Time
- Region: Aleutian Islands (Summer)
- DST: Daylight variant of HAST
UTC -08:00 to -05:00 (Americas)
UTC -08:00
- PST - Pacific Standard Time
- Region: US/Canada West Coast (Winter)
- DST: PDT -07:00
- Major Cities: Los Angeles, San Francisco, Seattle, Vancouver
- AKDT - Alaska Daylight Time
- Region: Alaska (Summer)
- DST: Daylight variant of AKST
UTC -07:00
- MST - Mountain Standard Time
- Region: US/Canada Mountain (Winter)
- DST: MDT -06:00
- Major Cities: Denver, Calgary, Phoenix (no DST)
- PDT - Pacific Daylight Time
- Region: US/Canada West Coast (Summer)
- DST: Daylight variant of PST
- PNT - Phoenix Time
- Region: Arizona (most)
- DST: No DST
- Notes: Arizona doesn't observe DST (except Navajo Nation)
UTC -06:00
- CST - Central Standard Time
- Region: US/Canada Central (Winter)
- DST: CDT -05:00
- Major Cities: Chicago, Mexico City, Winnipeg
- MDT - Mountain Daylight Time
- Region: US/Canada Mountain (Summer)
- DST: Daylight variant of MST
- GALT - Galapagos Time
- Region: Galapagos Islands
- DST: No DST
UTC -05:00
- EST - Eastern Standard Time
- Region: US/Canada East Coast (Winter)
- DST: EDT -04:00
- Major Cities: New York, Toronto, Miami
- CDT - Central Daylight Time
- Region: US/Canada Central (Summer)
- DST: Daylight variant of CST
- COT - Colombia Time
- Region: Colombia
- DST: No DST
- PET - Peru Time
- Region: Peru
- DST: No DST
UTC -04:00 to -01:00 (Atlantic & South America)
UTC -04:00
- EDT - Eastern Daylight Time
- Region: US/Canada East Coast (Summer)
- DST: Daylight variant of EST
- AST - Atlantic Standard Time
- Region: Atlantic Canada, Caribbean
- DST: ADT -03:00 (some regions)
- BOT - Bolivia Time
- Region: Bolivia
- DST: No DST
- VET - Venezuelan Standard Time
- Region: Venezuela
- DST: No DST
UTC -03:30
- NST - Newfoundland Standard Time
- Region: Newfoundland, Canada
- DST: NDT -02:30
- Notes: Unique half-hour offset
UTC -03:00
- ADT - Atlantic Daylight Time
- Region: Atlantic Canada (Summer)
- DST: Daylight variant of AST
- ART - Argentina Time
- Region: Argentina
- DST: No DST (since 2009)
- BRT - BrasĂlia Time
- Region: Eastern Brazil
- DST: BRST -02:00 (varies by year)
- FKST - Falkland Islands Summer Time
- Region: Falkland Islands
- DST: Daylight variant
- UYT - Uruguay Time
- Region: Uruguay
- DST: No DST currently
UTC -02:00
- BRST - BrasĂlia Summer Time
- Region: Eastern Brazil (Summer)
- DST: Daylight variant of BRT
- GST - South Georgia Time
- Region: South Georgia Island
- DST: No DST
UTC -01:00
- AZOT - Azores Standard Time
- Region: Azores, Portugal
- DST: AZOST +00:00
- CVT - Cape Verde Time
- Region: Cape Verde
- DST: No DST
- EGT - Eastern Greenland Time
- Region: Eastern Greenland
- DST: EGST +00:00
UTC +00:00 to +03:00 (Europe & Africa)
UTC +00:00
- GMT - Greenwich Mean Time
- Region: UK, Ireland (Winter)
- DST: BST +01:00
- Notes: Reference meridian
- UTC - Coordinated Universal Time
- Region: International Standard
- DST: No DST
- Notes: Scientific time standard
- WET - Western European Time
- Region: Portugal, Iceland (Winter)
- DST: WEST +01:00
UTC +01:00
- CET - Central European Time
- Region: Most of Western Europe (Winter)
- DST: CEST +02:00
- Major Cities: Paris, Berlin, Rome, Madrid
- BST - British Summer Time
- Region: UK, Ireland (Summer)
- DST: Daylight variant of GMT
- WEST - Western European Summer Time
- Region: Portugal (Summer)
- DST: Daylight variant of WET
- WAT - West Africa Time
- Region: West Central Africa
- DST: No DST
- Countries: Nigeria, Niger, Chad
UTC +02:00
- CEST - Central European Summer Time
- Region: Most of Western Europe (Summer)
- DST: Daylight variant of CET
- EET - Eastern European Time
- Region: Eastern Europe (Winter)
- DST: EEST +03:00
- Countries: Greece, Romania, Finland
- SAST - South African Standard Time
- Region: South Africa, Botswana
- DST: No DST
- CAT - Central Africa Time
- Region: Central Africa
- DST: No DST
- Countries: Zimbabwe, Zambia, Malawi
- IST - Israel Standard Time
- Region: Israel
- DST: IDT +03:00
UTC +03:00
- EEST - Eastern European Summer Time
- Region: Eastern Europe (Summer)
- DST: Daylight variant of EET
- EAT - East Africa Time
- Region: East Africa
- DST: No DST
- Countries: Kenya, Tanzania, Ethiopia
- MSK - Moscow Standard Time
- Region: Western Russia
- DST: No DST (since 2014)
- AST - Arabia Standard Time
- Region: Saudi Arabia, Iraq, Kuwait
- DST: No DST
- SYOT - Syowa Time
- Region: Antarctica (Syowa Station)
- DST: No DST
UTC +03:30 to +06:00 (Middle East & Central Asia)
UTC +03:30
- IRST - Iran Standard Time
- Region: Iran
- DST: IRDT +04:30
- Notes: Unique half-hour offset
UTC +04:00
- GET - Georgia Standard Time
- Region: Georgia
- DST: No DST
- AMT - Armenia Time
- Region: Armenia
- DST: No DST
- AZT - Azerbaijan Time
- Region: Azerbaijan
- DST: No DST
- GST - Gulf Standard Time
- Region: UAE, Oman
- DST: No DST
- MUT - Mauritius Time
- Region: Mauritius
- DST: No DST
UTC +04:30
- AFT - Afghanistan Time
- Region: Afghanistan
- DST: No DST
- Notes: Unique half-hour offset
UTC +05:00
- PKT - Pakistan Standard Time
- Region: Pakistan
- DST: No DST
- UZT - Uzbekistan Time
- Region: Uzbekistan
- DST: No DST
- YEKT - Yekaterinburg Time
- Region: West Siberia, Russia
- DST: No DST
- MAWT - Mawson Time
- Region: Antarctica (Mawson Station)
- DST: No DST
UTC +05:30
- IST - India Standard Time
- Region: India, Sri Lanka
- DST: No DST
- Notes: Unique half-hour offset
- Population: Over 1.4 billion people
UTC +05:45
- NPT - Nepal Time
- Region: Nepal
- DST: No DST
- Notes: Unique 45-minute offset
UTC +06:00
- BST - Bangladesh Standard Time
- Region: Bangladesh
- DST: No DST
- BTT - Bhutan Time
- Region: Bhutan
- DST: No DST
- KGT - Kyrgyzstan Time
- Region: Kyrgyzstan
- DST: No DST
- OMST - Omsk Standard Time
- Region: Omsk, Russia
- DST: No DST
UTC +06:30 to +09:00 (Asia)
UTC +06:30
- MMT - Myanmar Time
- Region: Myanmar (Burma)
- DST: No DST
- Notes: Unique half-hour offset
- CCT - Cocos Islands Time
- Region: Cocos Islands
- DST: No DST
UTC +07:00
- ICT - Indochina Time
- Region: Vietnam, Cambodia, Laos, Thailand
- DST: No DST
- WIB - Western Indonesian Time
- Region: Western Indonesia (Jakarta)
- DST: No DST
- KRAT - Krasnoyarsk Time
- Region: Krasnoyarsk, Russia
- DST: No DST
- NOVT - Novosibirsk Time
- Region: Novosibirsk, Russia
- DST: No DST
UTC +08:00
- CST - China Standard Time
- Region: Mainland China, Taiwan
- DST: No DST
- Notes: Single timezone for all of China
- HKT - Hong Kong Time
- Region: Hong Kong
- DST: No DST
- SGT - Singapore Time
- Region: Singapore
- DST: No DST
- PHT - Philippine Time
- Region: Philippines
- DST: No DST
- WITA - Central Indonesian Time
- Region: Central Indonesia (Bali)
- DST: No DST
- MYT - Malaysia Time
- Region: Malaysia
- DST: No DST
- AWST - Australian Western Standard Time
- Region: Western Australia
- DST: No DST (most of WA)
- IRKT - Irkutsk Time
- Region: Irkutsk, Russia
- DST: No DST
UTC +08:45
- ACWST - Australian Central Western Standard Time
- Region: Eucla, Western Australia
- DST: No DST
- Notes: Unique 45-minute offset, very small population
UTC +09:00
- JST - Japan Standard Time
- Region: Japan
- DST: No DST
- KST - Korea Standard Time
- Region: South Korea, North Korea
- DST: No DST
- WIT - Eastern Indonesian Time
- Region: Eastern Indonesia
- DST: No DST
- TLT - Timor Leste Time
- Region: East Timor
- DST: No DST
- YAKT - Yakutsk Time
- Region: Yakutsk, Russia
- DST: No DST
UTC +09:30 to +12:00 (Oceania)
UTC +09:30
- ACST - Australian Central Standard Time
- Region: South Australia, Northern Territory
- DST: ACDT +10:30 (SA only)
- Major Cities: Adelaide
UTC +10:00
- AEST - Australian Eastern Standard Time
- Region: Eastern Australia (Winter)
- DST: AEDT +11:00 (most areas)
- Major Cities: Sydney, Melbourne, Brisbane
- ACDT - Australian Central Daylight Time
- Region: South Australia (Summer)
- DST: Daylight variant of ACST
- ChST - Chamorro Standard Time
- Region: Guam, Northern Mariana Islands
- DST: No DST
- PGT - Papua New Guinea Time
- Region: Papua New Guinea
- DST: No DST
- VLAT - Vladivostok Time
- Region: Vladivostok, Russia
- DST: No DST
UTC +10:30
- LHST - Lord Howe Standard Time
- Region: Lord Howe Island
- DST: LHDT +11:00
- Notes: Unique half-hour offset and 30-minute DST shift
UTC +11:00
- AEDT - Australian Eastern Daylight Time
- Region: Eastern Australia (Summer)
- DST: Daylight variant of AEST
- NCT - New Caledonia Time
- Region: New Caledonia
- DST: No DST
- SBT - Solomon Islands Time
- Region: Solomon Islands
- DST: No DST
- VUT - Vanuatu Time
- Region: Vanuatu
- DST: No DST
- MAGT - Magadan Time
- Region: Magadan, Russia
- DST: No DST
UTC +12:00
- NZST - New Zealand Standard Time
- Region: New Zealand (Winter)
- DST: NZDT +13:00
- FJT - Fiji Time
- Region: Fiji
- DST: FJST +13:00 (some years)
- GILT - Gilbert Island Time
- Region: Kiribati (Gilbert Islands)
- DST: No DST
- PETT - Kamchatka Time
- Region: Kamchatka, Russia
- DST: No DST
- TVT - Tuvalu Time
- Region: Tuvalu
- DST: No DST
- WFT - Wallis and Futuna Time
- Region: Wallis and Futuna
- DST: No DST
UTC +12:45 to +14:00 (Far East Pacific)
UTC +12:45
- CHAST - Chatham Standard Time
- Region: Chatham Islands, New Zealand
- DST: CHADT +13:45
- Notes: Unique 45-minute offset
UTC +13:00
- NZDT - New Zealand Daylight Time
- Region: New Zealand (Summer)
- DST: Daylight variant of NZST
- PHOT - Phoenix Island Time
- Region: Phoenix Islands, Kiribati
- DST: No DST
- TOT - Tonga Time
- Region: Tonga
- DST: TOST +14:00 (some years)
- TKT - Tokelau Time
- Region: Tokelau
- DST: No DST
- FJST - Fiji Summer Time
- Region: Fiji (Summer, varies)
- DST: Daylight variant of FJT
UTC +13:45
- CHADT - Chatham Daylight Time
- Region: Chatham Islands (Summer)
- DST: Daylight variant of CHAST
UTC +14:00
- LINT - Line Islands Time
- Region: Line Islands, Kiribati
- DST: No DST
- Notes: One of the earliest timezones to see the new day
- TOST - Tonga Summer Time
- Region: Tonga (Summer, varies)
- DST: Daylight variant of TOT
Special Cases & Notes
Military Time Zones
Military uses single-letter timezone codes:
| Letter | UTC Offset | Name |
|---|---|---|
| Z | +00:00 | Zulu Time (UTC) |
| A | +01:00 | Alpha |
| B | +02:00 | Bravo |
| C | +03:00 | Charlie |
| D | +04:00 | Delta |
| E | +05:00 | Echo |
| F | +06:00 | Foxtrot |
| G | +07:00 | Golf |
| H | +08:00 | Hotel |
| I | +09:00 | India |
| K | +10:00 | Kilo |
| L | +11:00 | Lima |
| M | +12:00 | Mike |
| N | -01:00 | November |
| O | -02:00 | Oscar |
| P | -03:00 | Papa |
| Q | -04:00 | Quebec |
| R | -05:00 | Romeo |
| S | -06:00 | Sierra |
| T | -07:00 | Tango |
| U | -08:00 | Uniform |
| V | -09:00 | Victor |
| W | -10:00 | Whiskey |
| X | -11:00 | X-ray |
| Y | -12:00 | Yankee |
Note: Letter J is not used to avoid confusion with local time.
Ambiguous Abbreviations
Some timezone abbreviations are used for multiple regions:
- CST: Central Standard Time (US) OR China Standard Time OR Cuba Standard Time
- IST: India Standard Time OR Israel Standard Time OR Irish Standard Time
- AST: Atlantic Standard Time OR Arabia Standard Time
- BST: British Summer Time OR Bangladesh Standard Time
- GST: Gulf Standard Time OR South Georgia Time
Best Practice: Always use full timezone names or IANA timezone identifiers to avoid confusion.
Deprecated Timezones
Some timezone abbreviations are no longer officially used:
- PST8PDT → Use America/Los_Angeles
- EST5EDT → Use America/New_York
- CST6CDT → Use America/Chicago
No DST Regions
Major regions that don't observe Daylight Saving Time:
- Asia: Most of Asia (China, Japan, India, etc.)
- Africa: All of Africa
- Central/South America: Most countries
- Oceania: Queensland (Australia), Northern Territory (Australia)
- North America: Arizona (most), Hawaii, Saskatchewan
DST Transition Rules
United States & Canada
- Start: Second Sunday in March at 2:00 AM local time
- End: First Sunday in November at 2:00 AM local time
- Shift: Clocks move forward 1 hour in spring, back 1 hour in fall
European Union
- Start: Last Sunday in March at 1:00 AM UTC
- End: Last Sunday in October at 1:00 AM UTC
- Shift: Clocks move forward 1 hour in spring, back 1 hour in fall
- Note: EU voted to abolish DST, but implementation is pending
Australia
- Start: First Sunday in October at 2:00 AM local time
- End: First Sunday in April at 3:00 AM local time
- Regions: NSW, VIC, SA, TAS, ACT (QLD, NT, WA don't observe)
New Zealand
- Start: Last Sunday in September at 2:00 AM local time
- End: First Sunday in April at 3:00 AM local time
IANA Timezone Database
For programming, use IANA timezone identifiers instead of abbreviations:
Recommended Format
Continent/City
Examples
| Abbreviation | IANA Identifier | Recommended |
|---|---|---|
| EST/EDT | America/New_York | âś… |
| PST/PDT | America/Los_Angeles | âś… |
| CET/CEST | Europe/Paris | âś… |
| JST | Asia/Tokyo | âś… |
| AEST/AEDT | Australia/Sydney | âś… |
| IST | Asia/Kolkata | âś… (India) |
| IST | Asia/Jerusalem | âś… (Israel) |
Code Examples
JAVASCRIPT1// JavaScript - Use IANA identifiers 2const date = new Date(); 3const nyTime = date.toLocaleString('en-US', { timeZone: 'America/New_York' }); 4const tokyoTime = date.toLocaleString('en-US', { timeZone: 'Asia/Tokyo' });
PYTHON1# Python - Use pytz with IANA identifiers 2from datetime import datetime 3import pytz 4 5ny_tz = pytz.timezone('America/New_York') 6tokyo_tz = pytz.timezone('Asia/Tokyo') 7 8ny_time = datetime.now(ny_tz) 9tokyo_time = datetime.now(tokyo_tz)
Best Practices
When Working with Timezones
- Always use UTC internally - Convert to local timezones only for display
- Use IANA identifiers - More precise than abbreviations
- Never hardcode offsets - DST rules change
- Store timezone info with timestamps - Avoid ambiguity
- Be aware of DST transitions - Can cause duplicate or missing hours
- Test edge cases - Leap seconds, DST transitions, timezone changes
Common Pitfalls
❌ Avoid:
- Using timezone abbreviations in code (use IANA identifiers)
- Assuming all US states observe DST
- Forgetting that China has only one timezone
- Hardcoding DST transition dates
- Ignoring half-hour and 45-minute offsets
âś… Do:
- Use timezone-aware datetime objects
- Leverage timezone libraries (pytz, moment-timezone, etc.)
- Always include timezone information
- Test with different timezones
- Handle DST transitions gracefully