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GMT
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3am
6am
9am
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6pm
9pm
The United Kingdom is on summer time: BST (UTC+1) until Sun, Oct 25.

Iceland and Ghana stay on GMT (UTC+0).

CDT
12am
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6am
9am
12pm
3pm
6pm
9pm

Quick answers

Selected conversion

12:00 pm12:00 GMT (UTC+0), Oct 12, 2026 = 8:00 am08:00 CDT (UTC-4), Oct 12, 2026

GMT is 4 hours ahead of CDT.

GMT and CDT examples

These examples always use GMT (UTC+0) and CDT (UTC-4). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.

GMT is 4 hours ahead of CDT.

How the time difference changes

For most of the year, GMT is 4 hours ahead of CDT Caribbean. From Nov 1, 2026 to Mar 14, 2027, GMT is 5 hours ahead of CST Caribbean.

For most of the year, working hours of 9:00 am to 5:00 pm in GMT correspond to 5:00 am to 1:00 pm in CDT Caribbean. At other times of the year, working hours of 9:00 am to 5:00 pm in GMT correspond to 4:00 am to 12:00 pm in CST Caribbean.For most of the year, working hours of 09:00 to 17:00 in GMT correspond to 05:00 to 13:00 in CDT Caribbean. At other times of the year, working hours of 09:00 to 17:00 in GMT correspond to 04:00 to 12:00 in CST Caribbean.

Compare GMT time with CDT time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Greenwich Mean Time is 4 hours ahead of Cuba Daylight Time.
12:00 pm12:00 in GMT is 8:00 am08:00 in CDT

GMT to CDT call time
Best time for a conference call or a meeting is between 1pm-5pm13:00-17:00 in GMT which corresponds to 9am-1pm09:00-13:00 in CDT

12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
8:00 am08:00 Cuba Daylight Time (CDT). Offset UTC -4:00 hours

12:00 pm12:00 GMT / 8:00 am08:00 CDT

Choose an hour to update the converter. Day labels such as “next day” or “+1” are relative to the selected date in the first column. Use Up and Down arrow keys, Home or End to move between hours, then Enter or Space to select.

Hourly time comparison
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Greenwich Mean Time

Offset: GMT is the same as Greenwich Mean Time (GMT).

Countries using this time zone: Burkina Faso, Côte d'Ivoire, Britain (UK), Guernsey, Ghana, Greenland, Gambia, Guinea, Guinea-Bissau, Ireland, Isle of Man, Iceland, Jersey, Liberia, Mali, Mauritania, St Helena, Sierra Leone, Senegal, Sao Tome & Principe, Togo

Principal Cities: The largest city in the GMT time zone is London in the United Kingdom, with about 8.962 million people. Other major cities in this time zone include Abidjan, Bamako, Dakar, Kumasi.

Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use the two are the same. In the military, GMT is known as Zulu time. Greenwich Mean Time was the same as Universal Time (UT), a standard astronomical concept used in many technical fields, until the introduction of UTC in 1972.

Map of the areas on Greenwich Mean Time (GMT)
GMT all year GMT part of the year

Today the lighter areas are on UTC+1 (British Summer Time, Irish Standard Time).

GMT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • Z - is the zone designator for the zero UTC/GMT offset, also known as 'Zulu' time
  • +00 - basic short
  • +0000 - basic
  • +00:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0000 - sign character (+) followed by a four digit time providing hours (00) and minutes (00) of the offset. Indicates the zero UTC/GMT offset.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Zulu - Military abbreviation for GMT
  • Z - short form of 'Zulu'
IANA/Olson: Reflects GMT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Africa/Abidjan
  • Africa/Accra
  • Africa/Bamako
  • Africa/Banjul
  • Africa/Bissau
  • Africa/Conakry
  • Africa/Dakar
  • Africa/Freetown
  • Africa/Lome
  • Africa/Monrovia
  • Africa/Nouakchott
  • Africa/Ouagadougou
  • Africa/Sao_Tome
  • Africa/Timbuktu
  • America/Danmarkshavn
  • Atlantic/Reykjavik
  • Atlantic/St_Helena
  • Eire
  • Etc/GMT
  • Etc/GMT+0
  • Etc/GMT-0
  • Etc/GMT0
  • Etc/Greenwich
  • Europe/Belfast
  • Europe/Dublin
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
  • GMT
  • GMT+0
  • GMT-0
  • GMT0
  • Greenwich
  • Iceland
Time zones with the GMT +0 offset:
  • EGST - Eastern Greenland Summer Time
  • GMT - Greenwich Mean Time
  • WET - Western European Time
  • AZOST - Azores Summer Time
  • UTC - Coordinated Universal Time
  • WT - Western Sahara Standard Time
  • Z - Zulu Time Zone

Cuba Daylight Time

Offset: CDT is 4 hours behind Greenwich Mean Time (GMT).

Countries using this time zone: Cuba

Principal Cities: The largest city in the CDT time zone is Havana in Cuba, with about 2.164 million people. Other major cities in this time zone include Santiago de Cuba, Camagüey, Holguín, Guantánamo.

Map of the areas on Cuba Daylight Time (CDT)
CDT part of the year

Today all shaded areas are on CDT.

Daylight Saving: Cuba Daylight Time (CDT) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Cuba Standard Time (CST).

123456789101112Start: Cuba Daylight Time (CDT) started on Sunday, March 8, 2026 at 12:00 am00:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 1:00 am01:00. Daylight saving starts annually on the second Sunday of March.

123456789101112End: Cuba Daylight Time (CDT) ends on Sunday, November 1, 2026 at 1:00 am01:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 12:00 am00:00 local standard time instead. Daylight saving ends annually on the first Sunday of November.

See upcoming clock changes worldwide.

CDT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -04 - basic short
  • -0400 - basic
  • -04:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0400 - sign character (-) followed by a four digit time providing hours (04) and minutes (00) of the offset. Indicates an offset of four hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Quebec - Military abbreviation for CDT
  • Q - short form of 'Quebec'
IANA/Olson: Reflects CDT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Havana
  • Cuba
CDT Abbreviation: Several time zones share CDT abbreviation and it could refer to these time zones
  • Central Daylight Time - UTC -5
  • Cuba Daylight Time - UTC -4
Time zones with the GMT -4 offset:
  • AST - Atlantic Standard Time
  • EDT - Eastern Daylight Time
  • AMT - Amazon Time
  • BOT - Bolivia Time
  • CDT - Cuba Daylight Time
  • CLT - Chile Standard Time
  • FKT - Falkland Island Time
  • GYT - Guyana Time
  • HLV - Hora Legal de Venezuela
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time