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ADT/AST

Atlantic Daylight Time

GMT -3

12am

3am

6am

9am

12pm

3pm

6pm

9pm

Atlantic Time is on daylight saving time: ADT (UTC−3) until Sun, Nov 1.

Use AST all year (UTC−4)

CEST/CET

Central European Summer Time

GMT +2

12am

3am

6am

9am

12pm

3pm

6pm

9pm

Central Europe is on summer time: CEST (UTC+2) until Sun, Oct 25.

Use CET all year (UTC+1)

Quick answers

Selected conversion

9:00 am09:00 ADT (UTC-3), Oct 4, 2026 = 2:00 pm14:00 CEST (UTC+2), Oct 4, 2026

ADT is 5 hours behind CEST.

AST and CET examples

These examples always use AST (UTC-4) and CET (UTC+1). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.

AST is 5 hours behind CET.

How the time difference changes

For most of the year, ADT is 5 hours behind CEST. At other times of the year, AST is 5 hours behind CET or ADT is 4 hours behind CET.

For most of the year, working hours of 9:00 am to 5:00 pm in ADT correspond to 2:00 pm to 10:00 pm in CEST. At other times of the year, working hours of 9:00 am to 5:00 pm in AST correspond to 2:00 pm to 10:00 pm in CET or working hours of 9:00 am to 5:00 pm in ADT correspond to 1:00 pm to 9:00 pm in CET.For most of the year, working hours of 09:00 to 17:00 in ADT correspond to 14:00 to 22:00 in CEST. At other times of the year, working hours of 09:00 to 17:00 in AST correspond to 14:00 to 22:00 in CET or working hours of 09:00 to 17:00 in ADT correspond to 13:00 to 21:00 in CET.

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

Time Difference

Atlantic Daylight Time is 5 hours behind Central European Summer Time.
9:00 am09:00 in ADT is 2:00 pm14:00 in CEST

ADT to CEST call time
Best time for a conference call or a meeting is between 9am-12pm09:00-12:00 in ADT which corresponds to 2pm-5pm14:00-17:00 in CEST

9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
2:00 pm14:00 Central European Summer Time (CEST). Offset UTC +2:00 hours

9:00 am09:00 ADT / 2:00 pm14:00 CEST

ADT	CEST
12:00am	5:00am
1:00am	6:00am
2:00am	7:00am
3:00am	8:00am
4:00am	9:00am
5:00am	10:00am
6:00am	11:00am
7:00am	12:00pm
8:00am	1:00pm
9:00am	2:00pm
10:00am	3:00pm
11:00am	4:00pm
12:00pm	5:00pm
1:00pm	6:00pm
2:00pm	7:00pm
3:00pm	8:00pm
4:00pm	9:00pm
5:00pm	10:00pm
6:00pm	11:00pm
7:00pm	12:00am
8:00pm	1:00am
9:00pm	2:00am
10:00pm	3:00am
11:00pm	4:00am
00:00	05:00
01:00	06:00
02:00	07:00
03:00	08:00
04:00	09:00
05:00	10:00
06:00	11:00
07:00	12:00
08:00	13:00
09:00	14:00
10:00	15:00
11:00	16:00
12:00	17:00
13:00	18:00
14:00	19:00
15:00	20:00
16:00	21:00
17:00	22:00
18:00	23:00
19:00	00:00
20:00	01:00
21:00	02:00
22:00	03:00
23:00	04:00

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, Halifax, San Juan.

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).

End: Atlantic Standard Time (AST) ended on Sunday, March 8, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 3:00 am03:00 local daylight time instead. Standard time ends annually on the second Sunday of March.

Start: Atlantic Standard Time (AST) starts on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 1:00 am01:00. Standard time starts annually on the first Sunday of November.

See upcoming clock changes worldwide.

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

Central European Time

Offset: CET is 1 hour ahead Greenwich Mean Time (GMT) and is used in Europe

Countries using this time zone: Andorra, Albania, Austria, Bosnia & Herzegovina, Belgium, Switzerland, Czech Republic, Germany, Denmark, Algeria, Spain, France, Gibraltar, Croatia, Hungary, Italy, Liechtenstein, Luxembourg, Monaco, Montenegro, North Macedonia, Malta, Netherlands, Norway, Poland, Serbia, Sweden, Slovenia, Svalbard & Jan Mayen, Slovakia, San Marino, Tunisia, Vatican City

Principal Cities: The largest city in the CET time zone is Berlin in Germany, with about 3.426 million people. Other major cities in this time zone include Madrid, Algiers, Rome, Paris.

German: MEZ - Mitteleuropäische Zeit

CET Time Zone Geo Map — CET 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 Central European Summer Time (CEST).

End: Central European Time (CET) ended on Sunday, March 29, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 29, 2026, 3:00 am03:00 local daylight time instead. Standard time ends annually on the last Sunday of March.

Start: Central European Time (CET) starts on Sunday, October 25, 2026 at 3:00 am03:00 local time and clocks are set one hour back to Sunday, October 25, 2026, 2:00 am02:00. Standard time starts annually on the last Sunday of October.