This table contains a list of the time zones recognized by the International Telecommunication Union (ITU). The table includes the abbreviation, full name, location, and time zone for each time zone and a list of the countries that use each time zone. The table is organized in order of increasing time zone, starting with the time zones that are most behind Coordinated Universal Time (UTC) and ending with the time zones that are most ahead of UTC.
Time zones recognized by the International Telecommunication Union (ITU)
The table is organized in order of increasing time zone, starting with the time zones that are most behind Coordinated Universal Time (UTC) and ending with the time zones that are most ahead of UTC.
| Abbreviation | Full Name | Location | Time Zone | Countries |
| IDLW | International Date Line West | Between the 180th meridian and 173rd W | UTC-12:00 | Baker Island, Howland Island |
| CUT-11 | Coordinated Universal Time-11 | Baker Island and Howland Island | UTC-11:00 | American Samoa |
| HAST | Hawaii-Aleutian Standard Time | Most of Hawaii and the Aleutian Islands | UTC-10:00 | Hawaii, Aleutian Islands (USA), Johnston Atoll (USA) |
| MART | Marquesas Time | Marquesas Islands | UTC-09:30 | Marquesas Islands (French Polynesia) |
| AKST | Alaska Standard Time | Most of Alaska | UTC-09:00 | Alaska (USA), Gambier Islands (French Polynesia) |
| PST | Pacific Standard Time | Most of western North America | UTC-08:00 | USA (California, Nevada, most of Idaho, most of Oregon, most of Washington), Canada, Pitcairn Islands |
| MST | Mountain Standard Time | Most of western North America | UTC-07:00 | USA (Arizona, Colorado, Montana, New Mexico, Utah, Wyoming), Canada, Baja California |
| CST | Central Standard Time | Most of North America | UTC-06:00 | USA (Arkansas, Illinois, Indiana, Iowa, Kansas, Kentucky, Michigan, Minnesota, Missouri, Nebraska, Oklahoma, Texas), Canada (Manitoba, Ontario, Saskatchewan), Mexico (Mexico City, Tijuana), and Central America. |
| EST | Eastern Standard Time | Most of North America | UTC-05:00 | USA (Alabama, Florida, Georgia, Louisiana, Maine, Mississippi, New York, North Carolina, South Carolina, Vermont). |
| AST | Atlantic Standard Time | Most of eastern Canada and the Caribbean | UTC-04:00 | Canada: Most of eastern Canada (including the provinces of New Brunswick, Newfoundland and Labrador, Nova Scotia, and Prince Edward Island), Caribbean (Anguilla, Antigua and Barbuda, Aruba, Bahamas, Barbados, British Virgin Islands, Dominica, Grenada, Guadeloupe, Martinique, Montserrat, Puerto Rico, Saint Kitts and Nevis, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, Sint Maarten, Trinidad and Tobago, and the Turks and Caicos Islands), USA (Connecticut, Delaware, District of Columbia, Georgia, Kentucky, Maryland, Massachusetts, New Hampshire, New Jersey, New York, North Carolina, Ohio, Pennsylvania, Rhode Island, South Carolina, Tennessee, Vermont, Virginia, West Virginia) |
| NST | Newfoundland Standard Time | Newfoundland and Labrador, Canada | UTC-03:30 | Newfoundland and Labrador (Canada) |
| AST | Amazon Standard Time | Brazil, French Guiana, Guyana, Suriname | UTC-03:00 | Brazil, French Guiana, Guyana, Suriname, and most of eastern South America, including the following countries: Bolivia, Brazil (eastern states), Colombia (eastern states), Ecuador, Peru (eastern states), and Venezuela (eastern states). |
| FNT | Fernando de Noronha Time | Fernando de Noronha | UTC-02:00 | Fernando de Noronha (Brazil) |
| CVT | Cape Verde Time | Cape Verde Islands | UTC-01:00 | Cape Verde Islands |
| UTC | Coordinated Universal Time | Prime Meridian (0 degrees longitude) | UTC+00:00 | Senegal, Gambia, Guinea, Sierra Leone, Liberia, Ivory Coast, Burkina Faso, Ghana |
| WET | Western European Time | Most of western Europe | UTC+01:00 | Most of western Europe (Andorra, Belgium, France, Gibraltar, Ireland, Luxembourg, Monaco, Portugal, Spain), Algeria, Tunisia |
| CET | Central European Time | Most of central Europe | UTC+02:00 | Albania, Austria, Belgium, Bosnia and Herzegovina, Czech Republic, Denmark (except for the Faroe Islands), France (except for the overseas territories), Germany, Italy, Kosovo, Luxembourg, Monaco, Montenegro, Namibia, Netherlands, North Macedonia, Poland, Serbia, Slovakia, Slovenia, South Africa, Spain (Canary Islands only), Switzerland, Tunisia. |
| EET | Eastern European Time | Most of eastern Europe | UTC+03:00 | Most of eastern Europe (Belarus, Bulgaria, Cyprus, Estonia, Greece, Latvia, Lithuania, Moldova, Romania, Russia (Kaliningrad Oblast only), Israel, Palestine, Saudi Arabia, Iraq, Kuwait, Bahrain, Qatar, United Arab Emirates. |
| IRDT | Iran Daylight Time | Iran | UTC+03:30 | Iran |
| GST | Gulf Standard Time | United Arab Emirates, Oman | UTC+04:00 | Bahrain, Kuwait, Oman, Qatar, Saudi Arabia, United Arab Emirates |
| AFT | Afghanistan Time | Afghanistan | UTC+04:30 | Afghanistan |
| PKT | Pakistan Standard Time | Pakistan | UTC+05:00 | Pakistan, Kazakhstan (western part) |
| IST | India Standard Time | India | UTC+05:30 | India, Nepal, Maldives, Sri Lanka |
| NPT | Nepal Time | Nepal | UTC+05:45 | Nepal |
| BDT | Bangladesh Standard Time | Bangladesh | UTC+06:00 | Bangladesh, Bhutan, Kazakhstan (eastern part) |
| CIT | Cocos Islands Time | Cocos Islands | UTC+06:30 | Cocos Islands (Australia) |
International Telecommunication Union (ITU)
The International Telecommunication Union (ITU) is a United Nations agency that coordinates communication and information technology. One of the functions of the ITU is to define and maintain standardized time zones around the world. The ITU defines time zones based on the world’s 24 primary meridians, each 15 degrees apart and running north-south around the Earth.
The ITU recognizes a total of 40 time zones, which are generally centered around these 24 primary meridians. Each time zone is generally about 15 degrees wide, about one hour ahead or behind its neighboring time zones. Some time zones are slightly wider or narrower than 15 degrees to accommodate the needs of the countries within them.
The time zones recognized by the ITU are used by most countries worldwide, although some countries may use their own local time zones that differ slightly from the ITU time zones.
Some countries use their own local time zones
Some countries use their own local time zones that differ slightly from the time zones recognized by the International Telecommunication Union (ITU).
For example, China has one time zone for the entire country, which is 8 hours ahead of Coordinated Universal Time (UTC). However, the ITU recognizes two time zones for China: UTC+06:00 and UTC+08:00.
Similarly, India has one time zone for the entire country, which is 5 hours and 30 minutes ahead of UTC. The ITU recognizes two time zones for India: UTC+05:00 and UTC+05:30.
A few other countries have their own local time zones that differ slightly from the ITU time zones, such as Nepal, which is 5 hours and 45 minutes ahead of UTC, and Iran, which is 3 hours and 30 minutes ahead of UTC.
