AST to AEDT Converter
Convert time between Atlantic Standard Time (AST) and Australian Eastern Daylight Time (AEDT)
Atlantic Standard Time (AST)
Australian Eastern Daylight Time (AEDT)
Time Difference
Australian Eastern Daylight Time (AEDT) is 0 hours ahead of Atlantic Standard Time (AST)
Select Date
Select Time
Quick Reference
| AST | AEDT |
|---|---|
| 23:00 | 13:00 |
| 01:00 | 15:00 |
| 03:00 | 17:00 |
| 05:00 | 19:00 |
| 07:00 | 21:00 |
| 09:00 | 23:00 |
| 11:00 | 01:00 |
| 13:00 | 03:00 |
| 15:00 | 05:00 |
| 17:00 | 07:00 |
| 19:00 | 09:00 |
| 21:00 | 11:00 |
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
About AST to AEDT Time Conversion
Converting time between Atlantic Standard Time (AST, UTC-4) and Australian Eastern Daylight Time (AEDT, UTC+11) involves a 15-hour difference, with AEDT well ahead. AST is observed across Atlantic Canada during winter — covering Halifax, Saint John, and Moncton — while AEDT is active in Sydney, Melbourne, and Canberra during Australian summer (October to April).
This converter uses the IANA timezone database for accurate results. AST applies from early November to mid-March; outside this window, Atlantic Canada uses ADT (UTC-3). AEDT is itself a daylight saving timezone active October to April, reverting to AEST (UTC+10) in winter. Both regions' DST schedules overlap during the Atlantic winter / Australian summer period, when the 15-hour gap applies.
Common Use Cases for AST to AEDT Conversion
Business & Work
- Scheduling calls between Halifax or Moncton offices and Sydney or Melbourne teams
- Coordinating Atlantic Canadian and eastern Australian project timelines
- Planning cross-Pacific business meetings between Maritime Canadian and Australian partners
Personal & Travel
- Calling family and friends between Atlantic Canada and eastern Australia
- Planning travel from Halifax to Sydney or Melbourne
- Joining Australian-hosted online events or webinars from Atlantic Canada
Time Zone Information
Atlantic Standard Time (AST)
- UTC Offset: UTC-4 (UTC-3 ADT during summer)
- IANA Timezone: America/Halifax
- Daylight Saving: Second Sunday in March to First Sunday in November (switches to ADT, UTC-3)
- Major Cities: Halifax, Saint John, Moncton, Fredericton, Charlottetown
- Coverage: Nova Scotia, New Brunswick, Prince Edward Island, and parts of Quebec
Australian Eastern Daylight Time (AEDT)
- UTC Offset: UTC+11 (UTC+10 AEST during winter)
- IANA Timezone: Australia/Sydney
- Daylight Saving: First Sunday in October to First Sunday in April (AEDT, UTC+11)
- Major Cities: Sydney, Melbourne, Canberra, Hobart, Wollongong
- Coverage: New South Wales, Victoria, Tasmania, ACT during summer
Quick Reference: AST to AEDT
AEDT is 15 hours ahead of AST. AEDT is only active during Australian summer (Oct–Apr). When eastern Australia reverts to AEST (UTC+10), the gap narrows to 14 hours. When Atlantic Canada switches to ADT (UTC-3) in March, the gap with AEDT also drops to 14 hours.
Frequently Asked Questions
What is the time difference between AST and AEDT?
Atlantic Standard Time (AST) is UTC-4, while Australian Eastern Daylight Time (AEDT) is UTC+11. AEDT is 15 hours ahead of AST. For example, when it's 12:00 PM in Halifax (AST), it's 3:00 AM the next day in Sydney (AEDT).
When is AST observed?
Atlantic Standard Time (AST, UTC-4) is observed across Atlantic Canada from the first Sunday in November to the second Sunday in March. This covers Nova Scotia, New Brunswick, Prince Edward Island, and parts of Quebec. During the rest of the year, the region uses Atlantic Daylight Time (ADT, UTC-3), reducing the gap with AEDT to 14 hours.
When is AEDT observed?
Australian Eastern Daylight Time (AEDT, UTC+11) is observed in New South Wales, Victoria, Tasmania, and the ACT from the first Sunday in October to the first Sunday in April. Outside this period, these states use AEST (UTC+10), reducing the gap with AST to 14 hours. Queensland observes AEST year-round with no DST.
What are the best times for AST to AEDT business calls?
With a 15-hour gap, early evening in Halifax is most practical: 6:00–8:00 PM AST corresponds to 9:00–11:00 AM AEDT the next day in Sydney — within business hours for both sides. Alternatively, early morning Sydney (8–9 AM AEDT) aligns with 5:00–6:00 PM AST the previous day in Halifax.
Which Canadian provinces use AST?
AST is observed in Nova Scotia (Halifax), New Brunswick (Saint John, Moncton, Fredericton), Prince Edward Island (Charlottetown), and the eastern part of Quebec. It is also used in Bermuda and parts of the Caribbean. Newfoundland and Labrador use their own unique offset: NST (UTC-3:30), half an hour ahead of AST.
When are AST and AEDT active at the same time?
AST (UTC-4) applies November–March and AEDT (UTC+11) applies October–April. The overlap when both are simultaneously active is November through late March — Atlantic Canada winter coinciding with Australian summer. Outside this window one or both regions have changed clocks, shifting the gap to 14 hours.
Pro Tips
- • AEDT is 15 hours ahead of AST — evening Halifax (6–8 PM AST) maps neatly to business morning Sydney (9–11 AM AEDT next day).
- • Both AST and AEDT are seasonal — this 15-hour gap is only active November through late March.
- • Queensland (Brisbane) uses AEST (UTC+10) year-round — if your contact is in Brisbane, the gap from AST is always 14 hours.
- • Newfoundland uses NST (UTC-3:30), not AST — if your contact is in St. John's, add 30 minutes to AST times.
- • When Atlantic Canada moves to ADT (UTC-3) in March, the gap with AEDT drops to 14 hours — update recurring invites.
- • Use a dual world clock showing Halifax and Sydney to track the offset as both regions shift clocks in opposite hemispheres.
Update Logs
View the latest updates and features