GMT
Greenwich Mean Time
GMT +0
12am
3am
6am
9am
12pm
3pm
6pm
9pm
Y
Yankee Time Zone
GMT -12
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

GMT is 12 hours ahead of Y. GMT uses GMT +0, and Y uses GMT -12 for this comparison.

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

Best meeting overlap: 7pm-8pm GMT, which is 7am-8am Y.

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

Time Difference

Greenwich Mean Time is 12 hours ahead of Yankee Time Zone
12:00 pm12:00 in GMT is 12:00 am00:00 in Y

GMT to Y call time
Best time for a conference call or a meeting is between 7pm-8pm in GMT which corresponds to 7am-8am in Y

12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
12:00 am00:00 Yankee Time Zone (Y). Offset UTC -12:00 hours

12:00 pm12:00 GMT / 12:00 am00:00 Y

GMTY
12am (midnight)12pm (noon)
1am1pm
2am2pm
3am3pm
4am4pm
5am5pm
6am6pm
7am7pm
8am8pm
9am9pm
10am10pm
11am11pm
12pm (noon)12am (midnight)
1pm1am
2pm2am
3pm3am
4pm4am
5pm5am
6pm6am
7pm7am
8pm8am
9pm9am
10pm10am
11pm11am
00:0012:00
01:0013:00
02:0014:00
03:0015:00
04:0016:00
05:0017:00
06:0018:00
07:0019:00
08:0020:00
09:0021:00
10:0022:00
11:0023:00
12:0000:00
13:0001:00
14:0002:00
15:0003:00
16:0004:00
17:0005:00
18:0006:00
19:0007:00
20:0008:00
21:0009:00
22:0010:00
23:0011:00

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

Yankee Time Zone

Offset: Y is 12 hours behind Greenwich Mean Time (GMT) and is used in Military

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

Y representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -12 - basic short
  • -1200 - basic
  • -12:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -1200 - sign character (-) followed by a four digit time providing hours (12) and minutes (00) of the offset. Indicates an offset of twelve hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Yankee - Military abbreviation for Y
  • Y - short form of 'Yankee'