AST to AEDT Converter & Meeting Planner
Quick answer: 9:00 AM AST = 12:00 AM AEDT (fixed -04:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Atlantic Standard Time (AST) and Australian Eastern Daylight Time (AEDT)? You need to account for the standard time difference. Australian Eastern Daylight Time is normally 15 hours ahead of Atlantic Standard Time. Whether you are coordinating between teams in Halifax and San Juan and Sydney and Melbourne, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM AST = 3:00 PM AEDT. The full 24-hour AST to AEDT table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM AST = 6:00 AM AEDT (+1 day).
| AST Time | AEDT Time |
|---|---|
| 12:00 AM (00:00) | 3:00 PM (15:00) |
| 1:00 AM (01:00) | 4:00 PM (16:00) |
| 2:00 AM (02:00) | 5:00 PM (17:00) |
| 3:00 AM (03:00) | 6:00 PM (18:00) |
| 4:00 AM (04:00) | 7:00 PM (19:00) |
| 5:00 AM (05:00) | 8:00 PM (20:00) |
| 6:00 AM (06:00) | 9:00 PM (21:00) |
| 7:00 AM (07:00) | 10:00 PM (22:00) |
| 8:00 AM (08:00) | 11:00 PM (23:00) |
| 9:00 AM (09:00) | 12:00 AM (00:00)+1 day |
| 10:00 AM (10:00) | 1:00 AM (01:00)+1 day |
| 11:00 AM (11:00) | 2:00 AM (02:00)+1 day |
| 12:00 PM (12:00) | 3:00 AM (03:00)+1 day |
| 1:00 PM (13:00) | 4:00 AM (04:00)+1 day |
| 2:00 PM (14:00) | 5:00 AM (05:00)+1 day |
| 3:00 PM (15:00) | 6:00 AM (06:00)+1 day |
| 4:00 PM (16:00) | 7:00 AM (07:00)+1 day |
| 5:00 PM (17:00) | 8:00 AM (08:00)+1 day |
| 6:00 PM (18:00) | 9:00 AM (09:00)+1 day |
| 7:00 PM (19:00) | 10:00 AM (10:00)+1 day |
| 8:00 PM (20:00) | 11:00 AM (11:00)+1 day |
| 9:00 PM (21:00) | 12:00 PM (12:00)+1 day |
| 10:00 PM (22:00) | 1:00 PM (13:00)+1 day |
| 11:00 PM (23:00) | 2:00 PM (14:00)+1 day |
Best time to call Sydney from Halifax
For most work calls, compare the normal business day in Halifax (AST) with the business day in Sydney (AEDT). AST commonly covers North America, Caribbean, while AEDT is mainly associated with Oceania, Eastern Australia.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
⚠️ There is no clean same-day business-hours overlap on 2026-07-05. A practical compromise is around 8:00 PM AST, which reaches 9:00 AM AEDT near the start of their workday.
- DST Safety: AST or AEDT may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Australian Securities Exchange (ASX): 10:00-16:00 local time in Sydney.
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Frequently Asked Questions
What is the time difference between AST and AEDT?
During standard time, Australian Eastern Daylight Time is 15 hours ahead of Atlantic Standard Time.
Does the Caribbean observe Daylight Saving Time?
The vast majority of Caribbean nations and territories — including Puerto Rico, the Dominican Republic, the US Virgin Islands, Trinidad and Tobago, and Barbados — do not observe Daylight Saving Time and remain on AST (UTC-4) year-round. This means these territories share the same clock as Halifax only during the Atlantic Standard Time window in winter, diverging by one hour once Canada and Bermuda advance to ADT each spring.
What is the difference between AST and ADT?
AST (Atlantic Standard Time) is the standard winter offset at UTC-4:00, observed from the first Sunday in November through the second Sunday in March across all AST regions. ADT (Atlantic Daylight Time) is the summer offset at UTC-3:00, applied by Eastern Canadian provinces and Bermuda when they advance their clocks by one hour during Daylight Saving Time.
When does AEDT start and end?
AEDT begins on the first Sunday in October at 02:00 local time, when clocks spring forward one hour from AEST (UTC+10) to AEDT (UTC+11). It ends on the first Sunday in April at 03:00 local time, when clocks fall back to AEST. In 2026, AEDT starts on October 4 and ends on April 5 — following the Southern Hemisphere summer calendar, which runs opposite to DST schedules in Europe and North America.
Is Brisbane on AEDT?
No — Queensland, including Brisbane, does not observe Daylight Saving Time and remains on AEST (UTC+10) year-round. During the AEDT period from October through April, Sydney and Melbourne advance to UTC+11 while Brisbane stays at UTC+10, creating a one-hour gap between cities that share nearly the same longitude and are otherwise in the same time zone for the other six months of the year.