BST to ADT Converter
BST is not used on this date
This converter uses GMT (GMT +0), the offset London uses on this date. Open the GMT converter.ADT is not used on this date
This converter uses AST (GMT -4), the offset Moncton uses on this date. Open the AST converter.Compare BST time with ADT time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
Greenwich Mean Time is 4 hours ahead of Atlantic Standard Time
12:00 pm12:00 in GMT is 8:00 am08:00 in AST
GMT to AST call time
Best time for a conference call or a meeting is between 1pm-5pm in GMT which corresponds to 9am-1pm in AST
12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours
12:00 pm12:00 GMT / 8:00 am08:00 AST
| GMT | AST |
|---|---|
| 12am (midnight) | 8pm |
| 1am | 9pm |
| 2am | 10pm |
| 3am | 11pm |
| 4am | 12am (midnight) |
| 5am | 1am |
| 6am | 2am |
| 7am | 3am |
| 8am | 4am |
| 9am | 5am |
| 10am | 6am |
| 11am | 7am |
| 12pm (noon) | 8am |
| 1pm | 9am |
| 2pm | 10am |
| 3pm | 11am |
| 4pm | 12pm (noon) |
| 5pm | 1pm |
| 6pm | 2pm |
| 7pm | 3pm |
| 8pm | 4pm |
| 9pm | 5pm |
| 10pm | 6pm |
| 11pm | 7pm |
| 00:00 | 20:00 |
| 01:00 | 21:00 |
| 02:00 | 22:00 |
| 03:00 | 23:00 |
| 04:00 | 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 |
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 7.557 million people. Other major cities in this time zone include Birmingham, Glasgow, Liverpool, Saint Helier.
Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

BST representations, usage and related time zones
- +01 - basic short
- +0100 - basic
- +01:00 - extended
- +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.
- Alpha - Military abbreviation for BST
- A - short form of 'Alpha'
- Europe/Belfast
- Europe/Guernsey
- Europe/Isle_of_Man
- Europe/Jersey
- Europe/London
- GB
- GB-Eire
- British Summer Time - UTC +1
- Bangladesh Standard Time - UTC +6
- Bougainville Standard Time - UTC +11
- 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
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 359,111 people. Other major cities in this time zone include Sydney, Dartmouth, Saint John, Moncton.
French: HAA - Heure Avancée de l'Atlantique

Daylight Saving: Atlantic Daylight Time (ADT) is a daylight saving/summer time zone, but some places set clocks back one hour during winter and observe Atlantic Standard Time (AST).
End: Atlantic Daylight Time (ADT) ended 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 local standard time instead. Daylight saving ends annually on the first Sunday of November
Start: Atlantic Daylight Time (ADT) starts 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. Daylight saving starts annually on the second Sunday of March
ADT representations, usage and related time zones
- -03 - basic short
- -0300 - basic
- -03:00 - extended
- -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.
- Papa - Military abbreviation for ADT
- P - short form of 'Papa'
- America/Glace_Bay
- America/Goose_Bay
- America/Halifax
- America/Moncton
- America/Thule
- Atlantic/Bermuda
- Canada/Atlantic
- ADT - Atlantic Daylight Time
- PMT - Pierre & Miquelon Standard Time
- PMST - Pierre & Miquelon Standard Time
- AMST - Amazon Summer Time
- ART - Argentina Time
- BRT - BrasÃlia 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
