GMT
Greenwich Mean Time
GMT +0
12am
3am
6am
9am
12pm
3pm
6pm
9pm
HST
Hawaii Standard Time
GMT -10
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

GMT is 10 hours ahead of HST. GMT uses GMT +0, and HST uses GMT -10 for this comparison.

For example, 12:00 pm GMT is 2:00 am HST. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 5:30pm-6:30pm GMT, which is 7:30am-8:30am HST.

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

Time Difference

Greenwich Mean Time is 10 hours ahead of Hawaii Standard Time
12:00 pm12:00 in GMT is 2:00 am02:00 in HST

GMT to HST call time
Best time for a conference call or a meeting is between 5:30pm-6:30pm in GMT which corresponds to 7:30am-8:30am in HST

12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
2:00 am02:00 Hawaii Standard Time (HST). Offset UTC -10:00 hours

12:00 pm12:00 GMT / 2:00 am02:00 HST

GMTHST
12am (midnight)2pm
1am3pm
2am4pm
3am5pm
4am6pm
5am7pm
6am8pm
7am9pm
8am10pm
9am11pm
10am12am (midnight)
11am1am
12pm (noon)2am
1pm3am
2pm4am
3pm5am
4pm6am
5pm7am
6pm8am
7pm9am
8pm10am
9pm11am
10pm12pm (noon)
11pm1pm
00:0014:00
01:0015:00
02:0016:00
03:0017:00
04:0018:00
05:0019:00
06:0020:00
07:0021:00
08:0022:00
09:0023:00
10:0000:00
11:0001:00
12:0002:00
13:0003:00
14:0004:00
15:0005:00
16:0006:00
17:0007:00
18:0008:00
19:0009:00
20:0010:00
21:0011:00
22:0012:00
23:0013:00

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

Hawaii Standard Time

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

Countries using this time zone: United States

Principal Cities: The largest city in the HST time zone is Honolulu in the United States, with about 371,657 people. Other major cities in this time zone include Pearl City, Hilo, Kailua, Waipahu.

Daylight Saving: Clocks in Hawaii Standard Time (HST) do not change for daylight saving time, so HST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter.

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 an offset of ten hours 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