GMT
Greenwich Mean Time
GMT +0
HST
Hawaii Standard Time
GMT -10

Time Difference

Greenwich Mean Time is 10 hours ahead of Hawaii Standard Time
7:00 am07:00 in GMT is 9:00 pm21:00 in HST

GMT to HST call time
Best time for a conference call or a meeting is between 6pm-8pm in GMT which corresponds to 8am-10am in HST

7:00 am07:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
9:00 pm21:00 Hawaii Standard Time (HST). Offset UTC -10:00 hours

7:00 am07:00 GMT / 9:00 pm21:00 HST

GMT HST
12am (midnight) 2pm
1am 3pm
2am 4pm
3am 5pm
4am 6pm
5am 7pm
6am 8pm
7am 9pm
8am 10pm
9am 11pm
10am 12am (midnight)
11am 1am
12pm (noon) 2am
1pm 3am
2pm 4am
3pm 5am
4pm 6am
5pm 7am
6pm 8am
7pm 9am
8pm 10am
9pm 11am
10pm 12pm (noon)
11pm 1pm
0:00 14:00
1:00 15:00
2:00 16:00
3:00 17:00
4:00 18:00
5:00 19:00
6:00 20:00
7:00 21:00
8:00 22:00
9:00 23:00
10:00 0:00
11:00 1:00
12:00 2:00
13:00 3:00
14:00 4:00
15:00 5:00
16:00 6:00
17:00 7:00
18:00 8:00
19:00 9:00
20:00 10:00
21:00 11:00
22:00 12:00
23:00 13:00

Greenwich Mean Time

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

Countries: It is used in following countries: 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 timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are 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 zero hour and zero minutes time differences of the zero meridian.
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
GMT Abbreviation: Several time zones share GMT abbreviation and it could refer to these time zones
  • Greenwich Mean Time - UTC +0
  • GMT-05:00 - UTC -5
  • GMT+03:00 - UTC +3
  • GMT+04:00 - UTC +4
  • GMT+11:00 - UTC +11
  • GMT - UTC +1
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
  • GMT - GMT

Hawaii Standard Time

Offset: HST is 10 hours behind Greenwich Mean Time (GMT) and is used in Pacific

Countries: It is used in following countries: United States

Principal Cities: The largest city in the HST timezone is Honolulu from USA with population about 371,657 people. Other major cities in the area are Pearl City, Hilo, Kailua, Waipahu

Daylight Saving: This is a standard timezone, however during summer some places adjust time for one hour forward for daylight saving and observe Hawaii Daylight Time (HDT).

End: HST ended and clocks were set one hour forward on Sunday, 14 March 2021, at 2:00 (2:00 am) local time.

Start: HST starts and clocks are set one hour back on Sunday, 07 November 2021, at 2:00 (2:00 am) local time.

HST Time Zone Geo Map
HST timezone map

HST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -10 - basic short
  • -1000 - basic
  • -10:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -1000 - sign character (-) followed by a four digit time providing hours (10) and minutes (00) of the offset. Indicates ten hour and zero minutes time differences to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Whiskey - Military abbreviation for HST
  • W - short form of 'Whiskey'
IANA/Olson: Reflects HST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Adak
  • America/Atka
  • HST
  • Pacific/Honolulu
  • Pacific/Johnston
  • US/Aleutian
  • US/Hawaii
Time zones with the GMT -10 offset:
  • HAST - Hawaii-Aleutian Standard Time
  • CKT - Cook Island Time
  • HST - Hawaii Standard Time
  • TAHT - Tahiti Time
  • W - Whiskey Time Zone