Time Zone Abbreviations & UTC Offsets
Find out what EST, CEST, IST or AEDT stands for and how far it is from UTC. Search and sort 185 abbreviations, then switch to the live list of every IANA time zone with its current local time, UTC offset, abbreviation and daylight saving status, calculated in your browser.
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How to use the Time Zone Abbreviations & UTC Offsets
- Search an abbreviation such as IST or CEST in the Abbreviations tab, or filter by UTC offset or region.
- Check for ambiguity: the Notes column shows when the same letters mean different zones.
- Open Live IANA time zones to see the current time, offset and abbreviation for every zone, updated each second.
- Filter by continent or offset, or tick Observing DST now to list zones on summer time today.
- Copy a row or press Export CSV to download the filtered table.
The most searched abbreviations at a glance
| Abbreviation | Meaning | Standard | Summer (DST) | Used in |
|---|---|---|---|---|
| EST / EDT | Eastern Time | UTC−5 | UTC−4 | New York, Toronto, Miami |
| CST / CDT | Central Time | UTC−6 | UTC−5 | Chicago, Dallas, Winnipeg |
| MST / MDT | Mountain Time | UTC−7 | UTC−6 | Denver, Calgary (Phoenix: MST all year) |
| PST / PDT | Pacific Time | UTC−8 | UTC−7 | Los Angeles, Seattle, Vancouver |
| GMT / BST | UK time | UTC+0 | UTC+1 | London, Edinburgh |
| CET / CEST | Central European Time | UTC+1 | UTC+2 | Paris, Berlin, Madrid, Rome |
| EET / EEST | Eastern European Time | UTC+2 | UTC+3 | Athens, Helsinki, Kyiv, Bucharest |
| IST | India Standard Time | UTC+5:30 | — | All of India |
| JST | Japan Standard Time | UTC+9 | — | Tokyo, Osaka |
| AEST / AEDT | Australian Eastern Time | UTC+10 | UTC+11 | Sydney, Melbourne (Brisbane: AEST all year) |
| NZST / NZDT | New Zealand Time | UTC+12 | UTC+13 | Auckland, Wellington |
In North America the generic forms ET, CT, MT and PT mean "whatever is in effect", so "3 pm ET" is correct all year, while "3 pm EST" in July is technically wrong (it should be EDT).
When daylight saving time changes
- United States and Canada: clocks go forward at 2:00 local time on the second Sunday in March and back on the first Sunday in November.
- European Union and UK: forward at 01:00 UTC on the last Sunday in March and back at 01:00 UTC on the last Sunday in October, so all of Europe changes at the same moment.
- Australia (NSW, Victoria, ACT, Tasmania, South Australia): forward on the first Sunday in October and back on the first Sunday in April.
- New Zealand: forward on the last Sunday in September and back on the first Sunday in April.
- Chile: summer time runs from early September to early April, matching the southern hemisphere summer.
Because the northern and southern hemispheres switch in opposite seasons, the gap between, say, London and Sydney varies between 9, 10 and 11 hours during the year.
Reading UTC offsets
An offset tells you how far local time is ahead of (+) or behind (−) UTC. To convert a local time to UTC, subtract the offset: 15:00 at UTC+5:30 is 09:30 UTC, and 15:00 at UTC−4 is 19:00 UTC. Most offsets are whole hours, but India (+5:30), Iran (+3:30), Afghanistan (+4:30), Myanmar (+6:30), Newfoundland (−3:30), central Australia (+9:30), the Marquesas (−9:30), Nepal (+5:45) and the Chatham Islands (+12:45) are not. The full range runs from UTC−12 (Baker and Howland Islands) to UTC+14 (Kiribati's Line Islands), so at some moments three calendar dates are in use at once.
When storing or exchanging times, use ISO 8601 with an offset, such as 2026-10-19T15:00:00+02:00, or UTC with a Z, and keep the IANA zone name (for example Europe/Berlin) if future local times matter, because offsets and DST rules can change by law.
Frequently asked questions
What is the difference between GMT and UTC?
UTC (Coordinated Universal Time) is the atomic-clock time standard that all time zones are defined from. GMT (Greenwich Mean Time) is a time zone used by the UK, Ireland, Iceland and parts of West Africa, and it is always equal to UTC+0. In everyday use the two show the same clock time, but UTC is the standard and GMT is a zone.
Why do some abbreviations mean more than one time zone?
Abbreviations are not standardised, so different countries chose the same letters. IST can mean India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) or Israel Standard Time (UTC+2), and CST can be US Central, China or Cuba Standard Time. For anything important, write the UTC offset or the IANA zone name (for example Asia/Kolkata) instead.
What is an IANA time zone?
The IANA time zone database (also called tz or zoneinfo) names zones by region and city, such as America/New_York or Europe/Paris, and records every historical change to their offsets and daylight saving rules. Operating systems, browsers and programming languages use it, which is why the live list on this page is always as current as your browser.
How is the live data calculated?
Your browser's built-in Intl API is asked for the current UTC offset, short abbreviation and long name of each IANA zone. Daylight saving is detected by comparing the zone's offsets across the current year: the lower one is standard time and the higher one is daylight time. Nothing is downloaded from a server.
Why does a zone show GMT+X instead of letters?
Many zones have no widely used English abbreviation. When your browser's locale data (CLDR) has no common abbreviation for a zone, it shows the offset instead, for example GMT+4 for Asia/Dubai in some browsers. The full name column still identifies the zone.
Which countries do not use daylight saving time?
Most of Africa and Asia, nearly all of South America (Brazil stopped in 2019), Russia, Turkey, Iceland, Japan, China, India and the US states of Hawaii and Arizona (except the Navajo Nation) keep the same time all year. Use the Observing DST now filter to see which zones are currently on summer time.
Are the offsets correct for today?
The live tab uses the time zone rules built into your browser, so it reflects recent changes such as Kazakhstan moving to UTC+5 in 2024, as long as your browser is up to date. The abbreviation list shows the standard offset each abbreviation stands for.