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ADT to BST Converter

Updating current time…
ADT
Atlantic Daylight Time
GMT -3
12am
3am
6am
9am
12pm
3pm
6pm
9pm
BST
British Summer Time
GMT +1
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

Selected conversion

9:00 am09:00 ADT (UTC-3), Oct 7, 2026 = 1:00 pm13:00 BST (UTC+1), Oct 7, 2026

ADT is 4 hours behind BST.

ADT and BST examples

These examples always use ADT (UTC-3) and BST (UTC+1). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.

ADT is 4 hours behind BST.

How the time difference changes

For most of the year, ADT is 4 hours behind BST. At other times of the year, AST is 4 hours behind GMT or ADT is 3 hours behind GMT.

For most of the year, working hours of 9:00 am to 5:00 pm in ADT correspond to 1:00 pm to 9:00 pm in BST. At other times of the year, working hours of 9:00 am to 5:00 pm in AST correspond to 1:00 pm to 9:00 pm in GMT or working hours of 9:00 am to 5:00 pm in ADT correspond to 12:00 pm to 8:00 pm in GMT.For most of the year, working hours of 09:00 to 17:00 in ADT correspond to 13:00 to 21:00 in BST. At other times of the year, working hours of 09:00 to 17:00 in AST correspond to 13:00 to 21:00 in GMT or working hours of 09:00 to 17:00 in ADT correspond to 12:00 to 20:00 in GMT.

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

Time Difference

Atlantic Daylight Time is 4 hours behind British Summer Time.
9:00 am09:00 in ADT is 1:00 pm13:00 in BST

ADT to BST call time
Best time for a conference call or a meeting is between 9am-1pm09:00-13:00 in ADT which corresponds to 1pm-5pm13:00-17:00 in BST

9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
1:00 pm13:00 British Summer Time (BST). Offset UTC +1:00 hour

9:00 am09:00 ADT / 1:00 pm13:00 BST

ADTBST
12:00am4:00am
1:00am5:00am
2:00am6:00am
3:00am7:00am
4:00am8:00am
5:00am9:00am
6:00am10:00am
7:00am11:00am
8:00am12:00pm
9:00am1:00pm
10:00am2:00pm
11:00am3:00pm
12:00pm4:00pm
1:00pm5:00pm
2:00pm6:00pm
3:00pm7:00pm
4:00pm8:00pm
5:00pm9:00pm
6:00pm10:00pm
7:00pm11:00pm
8:00pm12:00am
9:00pm1:00am
10:00pm2:00am
11:00pm3:00am
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

Atlantic Daylight Time

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

Countries using this time zone: Bermuda, Canada, Greenland

Principal Cities: The largest city in the ADT time zone is Halifax in Canada, with about 471,559 people. Other major cities in this time zone include Sydney, Dartmouth, Moncton, Saint John.

French: HAA - Heure Avancée de l'Atlantique

ADT Time Zone Geo Map
ADT timezone map

Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Atlantic Standard Time (AST).

Daylight saving time clock moves forward for one hourStart: Atlantic Daylight Time (ADT) started 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. Daylight saving starts annually on the second Sunday of March.

Daylight saving time clock moves back for one hourEnd: Atlantic Daylight Time (ADT) ends 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 local standard time instead. Daylight saving ends annually on the first Sunday of November.

See upcoming clock changes worldwide.

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 an offset of three hours 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
  • 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

British Summer Time

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

Countries using this time zone: Britain (UK), Guernsey, Isle of Man, Jersey

Principal Cities: The largest city in the BST time zone is London in United Kingdom, with about 8.962 million people. Other major cities in this time zone include Birmingham, Glasgow, Liverpool, Saint Helier.

BST Time Zone Geo Map
BST timezone map

Daylight Saving: British Summer Time (BST) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Greenwich Mean Time (GMT).

Daylight saving time clock moves forward for one hourStart: British Summer Time (BST) started on Sunday, March 29, 2026 at 1:00 am01:00 local time and clocks were set one hour forward to Sunday, March 29, 2026, 2:00 am02:00. Daylight saving starts annually on the last Sunday of March.

Daylight saving time clock moves back for one hourEnd: British Summer Time (BST) ends on Sunday, October 25, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, October 25, 2026, 1:00 am01:00 local standard time instead. Daylight saving ends annually on the last Sunday of October.

See upcoming clock changes worldwide.

BST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +01 - basic short
  • +0100 - basic
  • +01:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates an offset of one hour to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Alpha - Military abbreviation for BST
  • A - short form of 'Alpha'
IANA/Olson: Reflects BST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Europe/Belfast
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
BST Abbreviation: Several time zones share BST abbreviation and it could refer to these time zones
  • British Summer Time - UTC +1
  • Bangladesh Standard Time - UTC +6
  • Bougainville Standard Time - UTC +11
Time zones with the GMT +1 offset:
  • BST - British Summer Time
  • CET - Central European Time
  • IST - Irish Standard Time
  • WEST - Western European Summer Time
  • A - Alpha Time Zone
  • CET - Central European Time
  • MEZ - Mitteleuropäische Zeit
  • WAT - West Africa Time
  • WST - Western Sahara Summer Time
  • BMT - Biel Mean Time
EST to ISTGMT to ESTPST to ESTEST to GMTPST to GMT