Time Zone Abbreviations

If you’re familiar with time zones, it’s useful to know some of the most commonly used time zone abbreviations. Knowing time zone abbreviations makes it easier to navigate time differences around the world: if you know what UTC, GMT, CET, or EST means, you can easily figure out what time it is in Europe, North America, or anywhere else around the world. It’s not necessary to know all the time zone abbreviations by heart (although, technically, this would save you time – pun intended), but it helps to quickly figure out which abbreviation stands for which time zone, especially if you’re scheduling social or business calls across different countries.

So let’s start at the beginning and first look at UTC and GMT abbreviations.

UTC and GMT

GMT stands for the Greenwich Mean Time, whereas UTC stands for the Coordinated Universal Time. What’s the difference? GMT is a time zone, whereas UTC is a time standard used for regulating the world’s clocks. GMT represents the Prime Meridian, or the zero longitude, whereas UTC represents the standard 0 hour time according to which all time zones are regulated. Anything West of GMT will have a negative time offset, whereas anything East of GMT will have a positive UTC offset. 

Countries and cities in the GMT time zone include: United Kingdom, Portugal, Canary Islands (Spain), Faroe Islands, Burkina Faso, Gambia, Ghana, Guinea, Guinea-Bissau, Iceland, Ivory Coast, Liberia, Mali, Mauritania, Saint Helena, Ascension and Tristan da Cunha, Senegal, Sierra Leone, and Togo.

DST: Daylight Savings Time

Besides GMT and UTC, another important abbreviation to remember is DST which stands for the Daylight Saving Time. Daylight Saving Time is used to extend daylight hours seasonally: some countries around the world use DST moving their clocks forward in summer and backward in winter to enjoy more daylight; however, not all countries use this practice, and not all people are happy with it. DST was first introduced during World War I as a means to save energy, and in most countries around the world, the concept stuck. However, this adds confusion to time zone differences: for example, Australian Eastern Time (AEST) is UTC +10, but between March and November, the locals move their clocks forward, and it becomes the Australian Eastern Daylight Time which is in UTC +11:00. This si done in many countries, states, and territories around the world, so when you’re trying to figure out time differences across the globe, make sure you take DST into account – sometimes, it may mean a difference of an hour you might forget to account for.

Now that you’ve got your GMT, UTC, and DST abbreviations figured out, let’s take a look at time zone abbreviations used around the world. Each time zone abbreviation corresponds to a specific time zone around the world, but it is not always defined by geography only – some countries and territories around the world choose to observe just one time zone, a time zone observed by its neighbours, or create their very own time zone or time offset.

Here is a comprehensive list of time zone abbreviations around the globe:

ACST: Australia Central Standard Time

Australia has several different time zones, and Australia Central Standard Time (ACST) stands for UTC+09:30, used in the central part of the country. Major cities in the Australia Central Standard Time include Darwin, Adelaide, and Alice Springs.

AEST: Australia Eastern Standard Time

Australia Eastern Standard Time is just half an hour ahead of ACST, falling on the UTC+10:00. AEST is observed in Eastern Australia with major cities like Melbourne, Sydney, and Brisbane in its sphere. Note that Eastern Australia switches to daylight savings time during the summer months, moving the clocks forward one hour and using the UTC+11:00 time zone.

AWST: Australia Western Standard Time

In Western Australia, locals observe the AWST, or the Australia Western Standard Time which is UTC +09:00. One of the biggest cities in AWST is Perth.

AFT: Afghanistan Time

Afghanistan is among the few countries that prefer an offset of half an hour rather than a full hour, making timekeeping in Kabul interesting. Afghanistan uses UTC+4.30, making the AFT a rather curious time zone.

AKST: Alaska Standard Time

Alaska Standard Time is an interesting one, too: despite the fact that Alaska’s territory spans over five time zones, the state uses just one – the AKST, or the Alaska Standard Time – for convenience. AKST is UTC-9:00, but during the summer months, it’s switched to Alaska Daylight Time.

AST: Atlantic Standard Time

AST, or the Atlantic Standard Time, is a good one to remember as it covers several countries like Antigua and Barbuda, Barbados, and the US Virgin Islands. Atlantic Standard Time is UTC-04:00, and from March to November, it changes to Atlantic Daylight Time one hour ahead.

CAT: Central Africa Time

What’s common between Botswana, Malawi, Namibia, Rwanda, and Sudan? The time zone! These countries observe CAT, or Central African Time, which is UTC +02:00. Essentially, CAT time is the same as GMT +2 time zone.

CET: Central European Time

Central European Time, or CET, is a time zone that covers a long list of European countries like Albania, Andorra, Austria, Belgium, Bosnia and Herzegovina, Croatia, Czech Republic, Denmark, France, Germany, Hungary, Italy, Kosovo, Liechtenstein, Luxembourg, Malta, Monaco, Montenegro, Netherlands, North Macedonia, Norway, Poland, San Marino, Serbia, Slovakia, Slovenia, Spain (except Canary Islands), Sweden, Switzerland, and Vatican City. CET is UTC+01:00, and major cities in this time zone include Amsterdam, Berlin, Warsaw, Brussels, Madrid, and Rome. Most countries in CET switch to daylight savings time during the summer months.

CST: Central Standard Time

CST, or Central Standard Time, covers the central part of the US and Canada. CST is UTC+06:00, and it covers Alabama, Arkansas, Illinois, Iowa, Louisiana, Minnesota, Mississippi, Missouri, Oklahoma, and Wisconsin in the US as well as Manitoba in Canada and several states in Mexico.

EAT: East Africa Time

EAT, or East Africa Time, is in UTC + 03:00, and it covers Kenya, Somalia, Madagascar, Ethiopia, Eritrea, Djibouti, Tanzania, and Uganda.

EET: Eastern European Time

EET stands for Easter European Time which is UTC +02:00, covering Bulgaria, Cyprus, Estonia, Finland, Greece, Latvia, Lithuania, Moldova, Romania, and Ukraine. Most of these countries observe daylight savings time.

EST: Eastern Standard Time

Eastern Standard Time, or EST, time zone covers large swaths of North, Central, and South America, and is UTC -05:00. Countries that use EST include United States, Canada, Mexico, Bahamas, Tahiti, Panama, Brazil, Colombia, Peru, and Ecuador.

MSK: Moscow Standard Time

Can a city have its very own time zone? Yes, if that city is Moscow: MSK stands for Moscow Standard Time, which is in UTC +03:00. MSK isn’t just used in Moscow, however: Belarus, parts of Ukraine, and parts of Russia also adhere to the Moscow Standard Time.

MST: Mountain Standard Time

MST, or Mountain Standard Time, is in UTC -07:00 and covers US states of Colorado, Montana, Wyoming, New Mexico, Arizona, and Utah. In Canada, the province of Alberta and part of British Columbia use MST, too, and in Mexico, Baja California, Chihuahua, Sonora, and Sinaloa fall under the Mountain Standard Time.

PST: Pacific Standard Time

If you work or communicate with people from LA or Las Vegas, PST, which stands for Pacific Standard Time, is an important abbreviation to remember. PST is UTC-08:00, and it covers the states of California, Washington, Idaho, Nevada, and Oregon in the US as well as British Columbia in Canada and part of Baja California in Mexico.

WAT: West Africa Time

WAT stands for West Africa Time which is UTC +01:00. WAT covers countries like Angola, Benin, Cameroon, Central African Republic, Chad, Congo, The Democratic Republic of Congo, Guinea, Gabon, Niger, and Nigeria.

WET: Western European Time

WET, or Western European Time, is the same time zone as GMT as it is in UTC 00:00. Countries in the Western European Time include the United Kingdom, Ireland, Iceland, and Portugal.

Once again, when calculating time differences between time zones, don’t forget to factor in the DST both in your own country and the one you’re determining the local time in. Whether the actual time zone offset is an hour, half an hour, or even just fifteen minutes (looking at you, Nepal!), if you don’t add the DST differences in, you may be way off when scheduling calls or meetings. And easy way to figure out whether a time zone abbreviation already has the DST factored in is to look for that “D”: for example, the Australian Eastern Time (AET) becomes the Australian Eastern Daylight Time (AEDT) during the summer, the “D” betraying the daylight savings. This is common across most time zone abbreviations regardless of geographical location.

Now that you know all the most commonly used time zone abbreviations, you’ll never mess up your work or social schedule whenever it involves international calls or meetings!