PT
Pacific Time
GMT -8
12am
3am
6am
9am
12pm
3pm
6pm
9pm
AST
Atlantic Standard Time
GMT -4
12am
3am
6am
9am
12pm
3pm
6pm
9pm

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

Time Difference

Pacific Time is 4 hours behind Atlantic Standard Time
4:00 am04:00 in PT is 8:00 am08:00 in AST

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

4:00 am04:00 Pacific Time (PT). Offset UTC -8:00 hours
8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours

4:00 am04:00 PT / 8:00 am08:00 AST

PTAST
12am (midnight)4am
1am5am
2am6am
3am7am
4am8am
5am9am
6am10am
7am11am
8am12pm (noon)
9am1pm
10am2pm
11am3pm
12pm (noon)4pm
1pm5pm
2pm6pm
3pm7pm
4pm8pm
5pm9pm
6pm10pm
7pm11pm
8pm12am (midnight)
9pm1am
10pm2am
11pm3am
00:0004:00
01:0005:00
02:0006:00
03:0007:00
04:0008:00
05:0009:00
06:0010:00
07:0011:00
08:0012:00
09:0013:00
10:0014:00
11:0015:00
12:0016:00
13:0017:00
14:0018:00
15:0019:00
16:0020:00
17:0021:00
18:0022:00
19:0023:00
20:0000:00
21:0001:00
22:0002:00
23:0003:00

Pacific Time

Pacific Time (PT) is a general term used to describe the areas that observe either the Pacific Standard Time (PST) or Pacific Daylight Time (PDT) in the United States and Canada. PT also called Pacific Coast Time. PT is not static but switches between PDT and PST.

Territories observing the Pacific Time Zone are primarily in North America. It runs through the western part of Canada, the United States and the Northwestern part of Mexico.

Countries using this time zone: Canada, Mexico, United States.

Principal Cities: The largest city in the PST time zone is Los Angeles in the United States, with about 3.793 million people. Other major cities in this time zone include Vancouver, Tijuana, San Diego, San Jose.

French: HNP - Heure Normale du Pacifique

Spanish: PT - Tiempo del Pacífico, PT - Zona Noroeste

PT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -08 - basic short
  • -0800 - basic
  • -08:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0800 - sign character (-) followed by a four digit time providing hours (08) and minutes (00) of the offset. Indicates an offset of eight hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Uniform - Military abbreviation for PT
  • U - short form of 'Uniform'
Time zones with the GMT -8 offset:
  • AKDT - Alaska Daylight Time
  • PST - Pacific Standard Time
  • PT - Pacific Time
  • PST - Pitcairn Standard Time
  • U - Uniform Time Zone

Atlantic Standard Time

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

Countries using this time zone: 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 time zone is Santo Domingo in Dominican Republic, with about 2.202 million people. Other major cities in this time zone include 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 time zone. During summer, some places set clocks forward one hour for daylight saving time 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 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am. Standard time starts annually on the 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 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am local daylight time instead. Standard time ends annually on the 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 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 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
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