BST to AST Converter
Convert time between British Summer Time (BST) and Atlantic Standard Time (AST)
British Summer Time (BST)
Atlantic Standard Time (AST)
Time Difference
Atlantic Standard Time (AST) is 0 hours ahead of British Summer Time (BST)
Select Date
Select Time
Quick Reference
| BST | AST |
|---|---|
| 02:00 | 22:00 |
| 04:00 | 00:00 |
| 06:00 | 02:00 |
| 08:00 | 04:00 |
| 10:00 | 06:00 |
| 12:00 | 08:00 |
| 14:00 | 10:00 |
| 16:00 | 12:00 |
| 18:00 | 14:00 |
| 20:00 | 16:00 |
| 22:00 | 18:00 |
| 00:00 | 20:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
Related Time Zone Conversions
About BST to AST Time Conversion
Converting time between British Summer Time (BST) and Atlantic Standard Time (AST) is essential for coordinating activities between the UK and Atlantic Canada during winter months. BST is UTC+1, while AST is UTC-4, making AST 5 hours behind BST.
This time zone converter uses the IANA timezone database to ensure accurate calculations, accounting for daylight saving time transitions and regional variations. Whether you're scheduling business meetings between London and Halifax, planning travel, or coordinating with teams across time zones, our converter provides reliable results. Atlantic Canada has significant maritime industries and is an important gateway for international trade.
Common Use Cases for BST to AST Conversion
Business & Work
- Scheduling meetings between UK and Atlantic Canada offices during winter
- Coordinating London and Halifax business operations
- Planning maritime and shipping coordination between UK and Canada
Personal & Travel
- Planning travel itineraries from UK to Atlantic Canada during winter
- Coordinating with family and friends in Nova Scotia and New Brunswick
- Scheduling virtual events with UK-Atlantic Canada audiences
Time Zone Information
British Summer Time (BST)
- UTC Offset: UTC+1 (UTC+0 during GMT)
- IANA Timezone: Europe/London
- Daylight Saving: Last Sunday in March to Last Sunday in October
- Major Cities: London, Manchester, Edinburgh, Cardiff, Belfast
- Coverage: United Kingdom and Ireland (during daylight saving time)
Atlantic Standard Time (AST)
- UTC Offset: UTC-4 (UTC-3 during ADT)
- IANA Timezone: America/Halifax
- Daylight Saving: Second Sunday in March to First Sunday in November (observes ADT)
- Major Cities: Halifax, Saint John, Charlottetown, St. John's
- Coverage: Atlantic provinces of Canada (Nova Scotia, New Brunswick, Prince Edward Island, Newfoundland and Labrador)
Quick Reference: BST to AST
Remember: AST is always 5 hours behind BST. In summer, Atlantic Canada uses ADT (UTC-3), making the difference 4 hours.
Frequently Asked Questions
What is the time difference between BST and AST?
British Summer Time (BST) is UTC+1, while Atlantic Standard Time (AST) is UTC-4. BST is 5 hours ahead of AST. This means when it's 6:00 PM in BST, it's 1:00 PM in AST. AST is used during winter months in the Atlantic provinces of Canada (November to March).
What's the difference between AST and ADT?
Atlantic Standard Time (AST) is UTC-4 and is used during winter months (November to March). Atlantic Daylight Time (ADT) is UTC-3 and is used during summer months (March to November). When the Atlantic region is in ADT (summer), the time difference from BST becomes 4 hours instead of 5. Always verify which is active when scheduling.
When should I use the BST to AST converter?
Use this converter when coordinating with the Atlantic region of Canada (Nova Scotia, New Brunswick, Prince Edward Island, Newfoundland and Labrador) during winter months (November to March) when AST is active. During summer months when ADT is active, use the BST to ADT converter for more accurate times.
What are the major cities in the AST timezone?
Major cities in Atlantic Standard Time include Halifax (Nova Scotia), Saint John (New Brunswick), Charlottetown (Prince Edward Island), and parts of Newfoundland and Labrador. These are important business, maritime, and shipping centers in Eastern Canada. The Atlantic provinces have significant tourism and natural resources industries.
How do I convert BST to AST manually?
To convert from BST to AST, subtract 5 hours from the BST time. For example, if it's 6:00 PM BST, it would be 1:00 PM AST. Remember this only applies during winter months when the Atlantic region uses AST. During summer when the Atlantic region observes ADT, the difference is 4 hours instead. Always check the current date to use the correct conversion.
What should I know about scheduling across BST and AST?
The UK and Atlantic Canada have similar working hour overlap as the US East Coast, but slightly more favorable. Morning BST times (8-10 AM) correspond to early morning AST (3-5 AM), which is quite early. Afternoon BST (2-4 PM) roughly aligns with late morning AST (9-11 AM), which is excellent for transatlantic scheduling. Late afternoon UK times (5-6 PM BST) work perfectly for early afternoon AST meetings (12-1 PM AST). Successful scheduling requires minimal flexibility compared to coordinating with the US West Coast.
Pro Tips
- • BST is 5 hours ahead of AST during winter months (November-March). Remember to switch to the BST to ADT converter when summer daylight saving time is active.
- • The UK observes daylight saving time with different dates than Atlantic Canada. UK changes: last Sunday of March/October. Atlantic Canada: second Sunday of March/first Sunday of November.
- • Early morning BST (8-10 AM) equals early morning AST (3-5 AM). While early, this is more manageable than coordinating with the US West Coast.
- • Afternoon BST (2-4 PM) roughly aligns with late morning AST (9-11 AM), which is the most practical window for transatlantic scheduling to avoid extreme hours.
- • Late afternoon UK times (5-6 PM BST) correspond to early afternoon Atlantic times (12-1 PM AST), making this the ideal window for important cross-timezone meetings.
- • Atlantic Canada includes important maritime and fishing industries, plus major ports. The region is also a gateway to the rest of North America for overseas trade.