AST/ADT
Atlantic Standard Time
GMT -4
ADT automatically adjusted to AST time zone, that is in use
EST/EDT
Eastern Standard Time
GMT -5
EDT automatically adjusted to EST time zone, that is in use

Time Difference

Atlantic Standard Time is 1 hour ahead of Eastern Standard Time
So 12:00 pm12:00 in AST is 11:00 am11:00 in EST

12:00 pm12:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours
11:00 am11:00 Eastern Standard Time (EST). Offset UTC -5:00 hours

12:00 pm12:00 AST / 11:00 am11:00 EST

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

Atlantic Daylight Time

Offset: ADT is 3 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries: It is used in following countries: Bermuda, Canada, Greenland

Principal Cities: The largest city in the ADT timezone is Halifax from Canada with population about 359,111 people. Other major cities in the area are Sydney, Dartmouth, Saint John, Moncton

Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer timezone, however during winter some places adjust time for one hour back and observe Atlantic Standard Time (AST).

End: ADT ended and clocks were set one hour back on Sunday, 01 November 2020, at 2:00 (2:00 am) local time.

Start: ADT starts and clocks are set one hour forward on Sunday, 14 March 2021, at 2:00 (2:00 am) local time.

French: HAA - Heure Avancée de l'Atlantique

ADT Time Zone Geo Map
ADT timezone map
ADT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -03 - basic short
  • -0300 - basic
  • -03:00 - extended

Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0300 - sign character (-) followed by a four digit time providing hours (03) and minutes (00) of the offset. Indicates three 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
  • Papa - Military abbreviation for ADT
  • P - short form of 'Papa'

IANA/Olson: Reflects ADT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Halifax
  • America/Moncton
  • America/Thule
  • Atlantic/Bermuda
  • Canada/Atlantic

Time zones with the GMT -3 offset:

  • ADT - Atlantic Daylight Time
  • PMT - Pierre & Miquelon Standard Time
  • PMST - Pierre & Miquelon Standard Time
  • WGT - West Greenland Time
  • AMST - Amazon Summer Time
  • ART - Argentina Time
  • BRT - Brasília time
  • CLST - Chile Summer Time
  • FKST - Falkland Islands Summer Time
  • GFT - French Guiana Time
  • P - Papa Time Zone
  • PYST - Paraguay Summer Time
  • SRT - Suriname Time
  • UYT - Uruguay Time
  • GMT - GMT-03:00
  • -03 -


Eastern Daylight Time

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

Countries: It is used in following countries: Bahamas, Canada, Haiti, Turks & Caicos Is, United States

Principal Cities: The largest city in the EDT timezone is New York City from USA with population about 8.175 million people. Other major cities in the area are Toronto, Montreal, Brooklyn, Borough of Queens

Daylight Saving: Eastern Daylight Time (EDT) is a daylight saving/summer timezone, however during winter some places adjust time for one hour back and observe Eastern Standard Time (EST).

End: EDT ended and clocks were set one hour back on Sunday, 01 November 2020, at 2:00 (2:00 am) local time.

Start: EDT starts and clocks are set one hour forward on Sunday, 14 March 2021, at 2:00 (2:00 am) local time.

French: HAE - Heure Avancée de l'Est

Spanish: EDT - Tiempo de verano del Este, ET - Zona Sureste

EDT Time Zone Geo Map
EDT timezone map
EDT 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 four 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
  • Quebec - Military abbreviation for EDT
  • Q - short form of 'Quebec'

IANA/Olson: Reflects EDT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Detroit
  • America/Fort_Wayne
  • America/Grand_Turk
  • America/Indiana/Indianapolis
  • America/Indiana/Marengo
  • America/Indiana/Petersburg
  • America/Indiana/Vevay
  • America/Indiana/Vincennes
  • America/Indiana/Winamac
  • America/Indianapolis
  • America/Iqaluit
  • America/Kentucky/Louisville
  • America/Kentucky/Monticello
  • America/Louisville
  • America/Montreal
  • America/Nassau
  • America/New_York
  • America/Nipigon
  • America/Pangnirtung
  • America/Port-au-Prince
  • America/Thunder_Bay
  • America/Toronto
  • Canada/Eastern
  • EST5EDT
  • US/East-Indiana
  • US/Eastern
  • US/Michigan

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
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time
  • -04 -