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GMT
Greenwich Mean Time
GMT +0
12am
3am
6am
9am
12pm
3pm
6pm
9pm
CST
Central Standard Time
GMT -6
12am
3am
6am
9am
12pm
3pm
6pm
9pm
CST/CDT
Central Standard Time
GMT -6
12am
3am
6am
9am
12pm
3pm
6pm
9pm
CDT is not used on this date
This converter uses CST (GMT -6), the offset Chicago uses on this date. Open the CST converter.

Quick answers

GMT to CST

For most of the year, GMT is 5 hours ahead of CDT. During seasonal clock changes, GMT is 6 hours ahead of CST.

For most 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 CDT. During seasonal clock changes, working hours of 9:00 am to 5:00 pm in GMT correspond to 3:00 am to 11:00 am in CST.

GMT to CDT

For most of the year, GMT is 5 hours ahead of CDT. During seasonal clock changes, GMT is 6 hours ahead of CST.

For most 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 CDT. During seasonal clock changes, working hours of 9:00 am to 5:00 pm in GMT correspond to 3:00 am to 11:00 am in CST.

Compare GMT time with CST and 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 6 hours ahead of Central Standard Time and 6 hours ahead of Central Standard Time
12:00 pm12:00 in GMT is 6:00 am06:00 in CST and is 6:00 am06:00 in CST

GMT to CST call time
Best time for a conference call or a meeting is between 3pm-5pm in GMT which corresponds to 9am-11am in CST
GMT to CST call time
Best time for a conference call or a meeting is between 3pm-5pm in GMT which corresponds to 9am-11am in CST

12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
6:00 am06:00 Central Standard Time (CST). Offset UTC -6:00 hours
6:00 am06:00 Central Standard Time (CST). Offset UTC -6:00 hours

12:00 pm12:00 GMT / 6:00 am06:00 CST / 6:00 am06:00 CST

GMTCSTCST
12am (midnight)6pm6pm
1am7pm7pm
2am8pm8pm
3am9pm9pm
4am10pm10pm
5am11pm11pm
6am12am (midnight)12am (midnight)
7am1am1am
8am2am2am
9am3am3am
10am4am4am
11am5am5am
12pm (noon)6am6am
1pm7am7am
2pm8am8am
3pm9am9am
4pm10am10am
5pm11am11am
6pm12pm (noon)12pm (noon)
7pm1pm1pm
8pm2pm2pm
9pm3pm3pm
10pm4pm4pm
11pm5pm5pm
00:0018:0018:00
01:0019:0019:00
02:0020:0020:00
03:0021:0021:00
04:0022:0022:00
05:0023:0023:00
06:0000:0000:00
07:0001:0001:00
08:0002:0002:00
09:0003:0003:00
10:0004:0004:00
11:0005:0005:00
12:0006:0006:00
13:0007:0007:00
14:0008:0008:00
15:0009:0009:00
16:0010:0010:00
17:0011:0011:00
18:0012:0012:00
19:0013:0013:00
20:0014:0014:00
21:0015:0015:00
22:0016:0016:00
23:0017:0017:00

Greenwich Mean Time

Offset: GMT is 0 hours ahead Greenwich Mean Time (GMT) and is used in Europe

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 United Kingdom, with about 7.557 million people. Other major cities in this time zone include Abidjan, Dakar, Grand Dakar, Accra.

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 for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

GMT Time Zone Geo Map
GMT timezone map

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 - Universal Time Coordinated
  • WT - Western Sahara Standard Time
  • Z - Zulu Time Zone

Central Standard Time

Offset: CST is 6 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Belize, Canada, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, El Salvador, United States

Principal Cities: The largest city in the CST time zone is Mexico City in Mexico, with about 12.294 million people. Other major cities in this time zone include Chicago, Houston, Iztapalapa, Ecatepec.

French: HNC - Heure Normale du Centre

Spanish: CT - Tiempo Central Estándar, CT - Zona Centro

CST Time Zone Geo Map
CST timezone map

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Central Daylight Time (CDT).

Daylight saving time clock moves back for one hour from 2am to 1amStart: Central Standard Time (CST) started on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am. Standard time starts annually on the first Sunday of November.

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Central Standard Time (CST) ends on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am local daylight time instead. Standard time ends annually on the second Sunday of March.

CST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -06 - basic short
  • -0600 - basic
  • -06:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0600 - sign character (-) followed by a four digit time providing hours (06) and minutes (00) of the offset. Indicates an offset of six hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Sierra - Military abbreviation for CST
  • S - short form of 'Sierra'
IANA/Olson: Reflects CST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Bahia_Banderas
  • America/Belize
  • America/Chicago
  • America/Chihuahua
  • America/Costa_Rica
  • America/El_Salvador
  • America/Guatemala
  • America/Indiana/Knox
  • America/Indiana/Tell_City
  • America/Knox_IN
  • America/Managua
  • America/Matamoros
  • America/Menominee
  • America/Merida
  • America/Mexico_City
  • America/Monterrey
  • America/North_Dakota/Beulah
  • America/North_Dakota/Center
  • America/North_Dakota/New_Salem
  • America/Ojinaga
  • America/Rainy_River
  • America/Rankin_Inlet
  • America/Regina
  • America/Resolute
  • America/Swift_Current
  • America/Tegucigalpa
  • America/Winnipeg
  • CST6CDT
  • Canada/Central
  • Canada/Saskatchewan
  • Mexico/General
  • US/Central
  • US/Indiana-Starke
CST Abbreviation: Several time zones share CST abbreviation and it could refer to these time zones
  • Central Standard Time - UTC -6
  • China Standard Time - UTC +8
  • Cuba Standard Time - UTC -5
Time zones with the GMT -6 offset:
  • CST - Central Standard Time
  • CT - Central Time
  • MDT - Mountain Daylight Time
  • EAST - Easter Island Standard Time
  • GALT - Galapagos Time
  • S - Sierra Time Zone

Central Daylight Time

Offset: CDT is 5 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Canada, Mexico, United States

Principal Cities: The largest city in the CDT time zone is Chicago in the United States, with about 2.696 million people. Other major cities in this time zone include Houston, Ciudad Juarez, San Antonio, Dallas.

French: HAC - Heure Avancée du Centre

Spanish: CT - Zona Centro

CDT Time Zone Geo Map
CDT timezone map

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

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Central Daylight Time (CDT) ended on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am local standard time instead. Daylight saving ends annually on the first Sunday of November

Daylight saving time clock moves back for one hour from 2am to 1amStart: Central Daylight Time (CDT) starts on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am. Daylight saving starts annually on the second Sunday of March

CDT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -05 - basic short
  • -0500 - basic
  • -05:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0500 - sign character (-) followed by a four digit time providing hours (05) and minutes (00) of the offset. Indicates an offset of five hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Romeo - Military abbreviation for CDT
  • R - short form of 'Romeo'
IANA/Olson: Reflects CDT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Chicago
  • America/Indiana/Knox
  • America/Indiana/Tell_City
  • America/Knox_IN
  • America/Matamoros
  • America/Menominee
  • America/North_Dakota/Beulah
  • America/North_Dakota/Center
  • America/North_Dakota/New_Salem
  • America/Ojinaga
  • America/Rainy_River
  • America/Rankin_Inlet
  • America/Resolute
  • America/Winnipeg
  • CST6CDT
  • Canada/Central
  • US/Central
  • US/Indiana-Starke
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 -5 offset:
  • CDT - Central Daylight Time
  • EST - Eastern Standard Time
  • ET - Eastern Time
  • COT - Colombia Time
  • CST - Cuba Standard Time
  • EASST - Easter Island Summer Time
  • ECT - Ecuador Time
  • PET - Peru Time
  • R - Romeo Time Zone