AST to EDT Converter
Convert time between Atlantic Standard Time (AST) and Eastern Daylight Time (EDT)
Atlantic Standard Time (AST)
Eastern Daylight Time (EDT)
Time Difference
Eastern Daylight Time (EDT) is 0 hours ahead of Atlantic Standard Time (AST)
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Select Time
Quick Reference
| AST | EDT |
|---|---|
| 22:00 | 21:00 |
| 00:00 | 23:00 |
| 02:00 | 01:00 |
| 04:00 | 03:00 |
| 06:00 | 05:00 |
| 08:00 | 07:00 |
| 10:00 | 09:00 |
| 12:00 | 11:00 |
| 14:00 | 13:00 |
| 16:00 | 15:00 |
| 18:00 | 17:00 |
| 20:00 | 19:00 |
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 AST to EDT Time Conversion
Converting time between Atlantic Standard Time (AST) and Eastern Daylight Time (EDT) is unique because both timezones share the same UTC offset. AST is UTC-4 (standard time in Atlantic Canada, used November to March) and EDT is UTC-4 (daylight time on the US East Coast, used March to November). This creates a remarkable 0-hour time difference - a rare occurrence in North American timezone conversions.
This conversion is most relevant during a specific seasonal window when the Eastern US has transitioned to daylight time (EDT, UTC-4) while Atlantic Canada is still on standard time (AST, UTC-4). This unusual alignment occurs from mid-March through early April and creates perfect timing synchronization between Atlantic Canada and the US East Coast. After Atlantic Canada transitions to Atlantic Daylight Time (ADT, UTC-3), the difference becomes 1 hour. This makes AST-EDT conversion one of the most unique and valuable timezone relationships for Atlantic-East Coast coordination.
Common Use Cases for AST to EDT Conversion
Business & Work
- Scheduling meetings between Atlantic Canada and US East Coast with zero time conversion needed
- Coordinating software development teams during perfect timezone alignment
- Managing business operations with East Coast partners without timezone offset complications
- Planning conference calls that perfectly align both regions' business hours
Personal & Travel
- Coordinating with family and friends on the US East Coast without time zone confusion
- Planning travel from Atlantic Canada to East Coast with no time adjustment needed
- Scheduling virtual meetings with East Coast relatives with perfect time synchronization
- Arranging online collaboration with East Coast-based colleagues in the same timezone
Time Zone Information
Atlantic Standard Time (AST)
- UTC Offset: UTC-4 (Winter standard time, November-March)
- IANA Timezone: America/Halifax
- Daylight Saving: Transitions to ADT (UTC-3) on second Sunday in March
- Major Cities: Halifax, Saint John, Charlottetown, Fredericton
- Coverage: Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island)
Eastern Daylight Time (EDT)
- UTC Offset: UTC-4 (Summer daylight time, March-November)
- IANA Timezone: America/New_York
- Daylight Saving: Active March to November. Transitions from EST (UTC-5) on second Sunday in March
- Major Cities: New York, Boston, Philadelphia, Atlanta, Washington DC
- Coverage: Eastern United States (summer months)
Quick Reference: AST to EDT
Remarkable: AST and EDT have the same UTC offset (UTC-4), creating 0-hour difference. This unique alignment makes Atlantic-East Coast coordination perfectly synchronized during this seasonal window. After Atlantic Canada transitions to ADT, the difference becomes 1 hour.
Frequently Asked Questions
What is the time difference between AST and EDT?
Atlantic Standard Time (AST) is UTC-4, while Eastern Daylight Time (EDT) is UTC-4. This means AST and EDT are in the same timezone - 0 hours difference! When it's 12:00 PM (noon) in Halifax (AST), it's 12:00 PM in New York (EDT). Note: This occurs during the brief spring transition window when Atlantic is still on standard time while the Eastern US has switched to daylight time. From March to November (when both are on daylight time), the difference remains 0 hours (ADT-EDT).
How is this possible - zero time difference between Atlantic Canada and the East Coast?
During a brief window in spring (roughly April to mid-March transition period), Atlantic Standard Time (AST, UTC-4) aligns perfectly with Eastern Daylight Time (EDT, UTC-4). This occurs because the East Coast transitions to daylight time (EDT, UTC-4) on the second Sunday in March, while Atlantic Canada doesn't transition to Atlantic Daylight Time (ADT, UTC-3) until the same date, but the UTC offset alignment creates this unique synchronization. This makes it the only timezone conversion where Atlantic Canada has zero offset with a major US region.
When is the AST to EDT conversion relevant?
The AST-EDT conversion is relevant from mid-April through early November when both regions are observing daylight time. However, during this period, Atlantic Canada is technically on ADT (UTC-3) and the East Coast is on EDT (UTC-4), creating a 1-hour difference. The true AST-EDT zero-difference window occurs only from the second Sunday in March (when East Coast switches to EDT) through early April (before Atlantic Canada officially recognizes the timezone change internally). After that, the practical difference becomes 1 hour (ADT-EDT).
What about during winter months?
During winter months (November to March), Atlantic Canada is on AST (UTC-4) while the Eastern US is on EST (UTC-5). This creates a 1-hour difference (AST is ahead). The AST-EDT conversion only applies during the specific transition period when the East Coast has switched to daylight time but Atlantic Canada hasn't yet adjusted its official timezone designation. After the second Sunday in March, Atlantic Canada transitions to ADT (UTC-3), creating a 1-hour difference (ADT is behind EDT).
What are the best times to schedule calls between Atlantic Canada and the East Coast?
Year-round, the Atlantic Canada-East Coast relationship is ideal for scheduling. When times align perfectly (AST-EDT), any time works. When there's a 1-hour difference (winter with AST-EST or summer with ADT-EDT), the offset is minimal. Atlantic morning (8 AM-12 PM) overlaps with East Coast morning (7-11 AM or 8 AM-1 PM depending on season). Afternoon calls work equally well: 2-5 PM East Coast aligns with 3-6 PM Atlantic or 2-5 PM Atlantic depending on daylight saving status. Standard business hours align almost perfectly.
Why is this special for Atlantic-East Coast coordination?
The AST-EDT conversion is unique because it represents the closest possible time alignment between Atlantic Canada and the United States. The East Coast is Atlantic Canada's primary economic partner, and this minimal offset (0 to 1 hour depending on season) makes coordination nearly effortless. The fact that times align perfectly for part of the year makes the East Coast the premier choice for Atlantic Canadian businesses seeking seamless US coordination. Combined with the region's economic importance (finance, tech, government), it's the optimal partnership zone.
Pro Tips
- • AST and EDT are the same UTC offset (UTC-4). This creates a unique 0-hour difference - the only Atlantic-US timezone pair with perfect alignment!
- • This zero-difference window exists from mid-March through early April, creating a special coordination period where no time conversion is needed.
- • Most of the year, the difference is 1 hour: either AST-EST (winter) or ADT-EDT (summer). Both are minimal compared to other Atlantic-US region pairs.
- • Schedule during the 9-11 AM Atlantic window (same time EDT, or 8-10 AM EDT in summer) for peak productivity in both regions simultaneously.
- • The East Coast is Atlantic Canada's natural economic partner. The minimal timezone offset makes it the easiest US region for coordination.
- • Mark transition dates: second Sunday in March (East Coast to EDT, Atlantic still on AST), and first Sunday in November (both to standard time).
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