GMT
Greenwich Mean Time
GMT +0
12am
3am
6am
9am
12pm
3pm
6pm
9pm
AMT
Amazon Time
GMT -4
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

GMT is 4 hours ahead of AMT. GMT uses GMT +0, and AMT uses GMT -4 for this comparison.

For example, 12:00 pm GMT is 8:00 am AMT. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 1pm-5pm GMT, which is 9am-1pm AMT.

Compare GMT time with AMT 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 Amazon Time
12:00 pm12:00 in GMT is 8:00 am08:00 in AMT

GMT to AMT call time
Best time for a conference call or a meeting is between 1pm-5pm in GMT which corresponds to 9am-1pm in AMT

12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
8:00 am08:00 Amazon Time (AMT). Offset UTC -4:00 hours

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

GMTAMT
12am (midnight)8pm
1am9pm
2am10pm
3am11pm
4am12am (midnight)
5am1am
6am2am
7am3am
8am4am
9am5am
10am6am
11am7am
12pm (noon)8am
1pm9am
2pm10am
3pm11am
4pm12pm (noon)
5pm1pm
6pm2pm
7pm3pm
8pm4pm
9pm5pm
10pm6pm
11pm7pm
00:0020:00
01:0021:00
02:0022:00
03:0023:00
04:0000:00
05:0001:00
06:0002:00
07:0003:00
08:0004:00
09:0005:00
10:0006:00
11:0007:00
12:0008:00
13:0009:00
14:0010:00
15:0011:00
16:0012:00
17:0013:00
18:0014:00
19:0015:00
20:0016:00
21:0017:00
22:0018:00
23:0019:00

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

Amazon Time

Offset: AMT is 4 hours behind Greenwich Mean Time (GMT) and is used in South America

Countries using this time zone: Brazil

Principal Cities: The largest city in the AMT time zone is Manaus in Brazil, with about 1.598 million people. Other major cities in this time zone include Itacoatiara, Parintins, Manacapuru, Coari.

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

AMT Time Zone Geo Map
AMT timezone map

AMT 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 AMT
  • Q - short form of 'Quebec'
AMT Abbreviation: Several time zones share AMT abbreviation and it could refer to these time zones
  • Armenia Time - UTC +4
  • Amazon 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