AST
Atlantic Standard Time
GMT -4
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
9:00 pm21:00 in AST is 8:00 pm20:00 in EST

AST to EDT call time
Best time for a conference call or a meeting is between 8am-6pm in AST which corresponds to 8am-6pm in EDT

9:00 pm21:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours
8:00 pm20:00 Eastern Standard Time (EST). Offset UTC -5:00 hours

9:00 pm21:00 AST / 8:00 pm20:00 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 Standard Time

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

Countries: It is used in following countries: Antigua & Barbuda, Anguilla, Aruba, Barbados, St Barthelemy, Bermuda, Caribbean NL, Canada, Curaçao, Dominica, Dominican Republic, Grenada, Greenland, Guadeloupe, St Kitts & Nevis, St Lucia, St Martin (French), Martinique, Montserrat, Puerto Rico, St Maarten (Dutch), Trinidad & Tobago, St Vincent, Virgin Islands (UK), Virgin Islands (US)

Principal Cities: The largest city in the AST timezone is Santo Domingo from Dominican Republic with population about 2.202 million people. Other major cities in the area are Santiago de los Caballeros, Santo Domingo Oeste, San Juan, Halifax

French: HNA - Heure Normale de l'Atlantique

Spanish: AST - Tiempo Estándar del Atlántico

AST Time Zone Geo Map
AST timezone map

Daylight Saving: This is a standard timezone, however during summer some places switch clocks for one hour forward when daylight saving comes into effect and observe Atlantic Daylight Time (ADT).

Daylight saving time clock moves back for one hour from 2am to 1amStart: Atlantic Standard Time (AST) started on Sunday, November 7, 2021 at 2:00 am local time and clocks were set one hour back to Sunday, November 7, 2021, 1:00 am. Standard time starts annually the on first Sunday of November.

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Atlantic Standard Time (AST) ends on Sunday, March 13, 2022 at 2:00 am local time and clocks are set one hour forward to Sunday, March 13, 2022, 3:00 am local daylight time instead. Standard time starts annually the on second Sunday of March.

AST 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 AST
  • Q - short form of 'Quebec'
IANA/Olson: Reflects AST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Anguilla
  • America/Antigua
  • America/Aruba
  • America/Barbados
  • America/Blanc-Sablon
  • America/Curacao
  • America/Dominica
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Grenada
  • America/Guadeloupe
  • America/Halifax
  • America/Kralendijk
  • America/Lower_Princes
  • America/Marigot
  • America/Martinique
  • America/Moncton
  • America/Montserrat
  • America/Port_of_Spain
  • America/Puerto_Rico
  • America/Santo_Domingo
  • America/St_Barthelemy
  • America/St_Kitts
  • America/St_Lucia
  • America/St_Thomas
  • America/St_Vincent
  • America/Thule
  • America/Tortola
  • America/Virgin
  • Atlantic/Bermuda
  • Canada/Atlantic
AST Abbreviation: Several time zones share AST abbreviation and it could refer to these time zones
  • Atlantic Standard Time - UTC -4
  • Arabia Standard Time - UTC +3
  • Arabian Standard Time - UTC +3
  • Acre Standard Time - UTC -5
  • Azores Standard Time - UTC -1
  • Apia Standard Time - UTC +13
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

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

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

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

Daylight saving time clock moves back for one hour from 2am to 1amEnd: Eastern Daylight Time (EDT) has ended on Sunday, November 7, 2021 at 2:00 am local time and clocks were set one hour back to Sunday, November 7, 2021, 1:00 am local standard time instead. Daylight saving ends annually the on first Sunday of November

Daylight saving time clock moves forward for one hour from 2am to 3amStart: Eastern Daylight Time (EDT) starts on Sunday, March 13, 2022 at 2:00 am local time and clocks are set one hour forward to Sunday, March 13, 2022, 3:00 am. Daylight saving starts annually the on second Sunday of March

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
  • HLV - Hora Legal de Venezuela
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time