AST to BST Converter
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Quick answers
Selected conversion
8:00 am08:00 AST (UTC-4), Nov 10, 2026 = 12:00 pm12:00 GMT (UTC+0), Nov 10, 2026
AST is 4 hours behind GMT.
AST and BST examples
These examples always use AST (UTC-4) 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.
AST is 5 hours behind BST.
How the time difference changes
For most of the year, ADT is 4 hours behind BST. From Nov 1, 2026 to Mar 14, 2027, and from Nov 7, 2027 to Mar 12, 2028, AST is 4 hours behind GMT. From Mar 14 to Mar 28, 2027, and from Oct 31 to Nov 7, 2027, ADT is 3 hours behind GMT.
For most of the year, working hours of 9:00 am to 6:00 pm in ADT correspond to 1:00 pm to 10:00 pm in BST. At other times of the year, working hours of 9:00 am to 6:00 pm in AST correspond to 1:00 pm to 10:00 pm in GMT or working hours of 9:00 am to 6:00 pm in ADT correspond to 12:00 pm to 9:00 pm in GMT.For most of the year, working hours of 09:00 to 18:00 in ADT correspond to 13:00 to 22:00 in BST. At other times of the year, working hours of 09:00 to 18:00 in AST correspond to 13:00 to 22:00 in GMT or working hours of 09:00 to 18:00 in ADT correspond to 12:00 to 21:00 in GMT.
Compare AST time with BST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
Atlantic Standard Time is 4 hours behind Greenwich Mean Time.
8:00 am08:00 in AST is 12:00 pm12:00 in GMT
AST to GMT call time
Best time for a conference call or a meeting is between 9am-2pm09:00-14:00 in AST which corresponds to 1pm-6pm13:00-18:00 in GMT.
8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours
12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
8:00 am08:00 AST / 12:00 pm12:00 GMT
Choose an hour to update the converter. Day labels such as “next day” or “+1” are relative to the selected date in the first column. Use Up and Down arrow keys, Home or End to move between hours, then Enter or Space to select.
| AST | GMT |
|---|---|
| 4:00am | |
| 5:00am | |
| 6:00am | |
| 7:00am | |
| 8:00am | |
| 9:00am | |
| 10:00am | |
| 11:00am | |
| 12:00pm | |
| 1:00pm | |
| 2:00pm | |
| 3:00pm | |
| 4:00pm | |
| 5:00pm | |
| 6:00pm | |
| 7:00pm | |
| 8:00pm | |
| 9:00pm | |
| 10:00pm | |
| 11:00pm | |
| 12:00am next day | |
| 1:00am next day | |
| 2:00am next day | |
| 3:00am next day | |
| 04:00 | |
| 05:00 | |
| 06:00 | |
| 07:00 | |
| 08:00 | |
| 09:00 | |
| 10:00 | |
| 11:00 | |
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| 22:00 | |
| 23:00 | |
| 00:00 next day | |
| 01:00 next day | |
| 02:00 next day | |
| 03:00 next day |
Atlantic Standard Time
Offset: AST is 4 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: Anguilla, Antigua and Barbuda, Aruba, Barbados, Bermuda, British Virgin Islands, Canada, Caribbean Netherlands, Curaçao, Dominica, Dominican Republic, Greenland, Grenada, Guadeloupe, Martinique, Montserrat, Puerto Rico, Saint Barthélemy, Saint Kitts and Nevis, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, Sint Maarten, Trinidad and Tobago, US Virgin Islands
Principal Cities: The largest city in the AST time zone is Santo Domingo in the Dominican Republic, with about 2.202 million people. Other major cities in this time zone include Santiago de los Caballeros, Halifax, San Juan, San Pedro de Macorís.
French: HNA - Heure Normale de l'Atlantique
Spanish: AST - Tiempo Estándar del Atlántico
Today all shaded areas are on AST.
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).
Start: Atlantic Standard Time (AST) started on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks were set one hour back to Sunday, November 1, 2026, 1:00 am01:00. Standard time starts annually on the first Sunday of November.
End: Atlantic Standard Time (AST) ends on Sunday, March 14, 2027 at 2:00 am02:00 local time and clocks are set one hour forward to Sunday, March 14, 2027, 3:00 am03:00 local daylight time instead. Standard time ends annually on the second Sunday of March.
See Canada daylight saving time and upcoming clock changes worldwide.
AST representations, usage and related time zones
- -04 - basic short
- -0400 - basic
- -04:00 - extended
- -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.
- Quebec - Military abbreviation for AST
- Q - short form of 'Quebec'
- 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
- Atlantic Standard Time - UTC -4
- Arabia Standard Time - UTC +3
- AST - Atlantic Standard Time
- EDT - Eastern Daylight Time
- AMT - Amazon Time
- BOT - Bolivia Time
- CDT - Cuba Daylight Time
- CLT - Chile Standard Time
- GYT - Guyana Time
- HLV - Hora Legal de Venezuela
- Q - Quebec Time Zone
- VET - Venezuelan Standard Time
British Summer Time
Offset: BST is 1 hour ahead of Greenwich Mean Time (GMT).
Countries using this time zone: Guernsey, Isle of Man, Jersey, United Kingdom
Principal Cities: The largest city in the BST time zone is London in the United Kingdom, with about 8.962 million people. Other major cities in this time zone include Birmingham, Glasgow, Manchester, Sheffield.
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 the two are the same. In the military, GMT is known as Zulu time. Greenwich Mean Time was the same as Universal Time (UT), a standard astronomical concept used in many technical fields, until the introduction of UTC in 1972.
Current time in the United Kingdom: UK time now
Today the shaded areas are on UTC+0 (GMT).
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