EDT to AST Converter
Convert time between Eastern Daylight Time (EDT) and Atlantic Standard Time (AST)
Eastern Daylight Time (EDT)
Atlantic Standard Time (AST)
Time Difference
Atlantic Standard Time (AST) is 0 hours ahead of Eastern Daylight Time (EDT)
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Select Time
Quick Reference
| EDT | AST |
|---|---|
| 21:00 | 22:00 |
| 23:00 | 00:00 |
| 01:00 | 02:00 |
| 03:00 | 04:00 |
| 05:00 | 06:00 |
| 07:00 | 08:00 |
| 09:00 | 10:00 |
| 11:00 | 12:00 |
| 13:00 | 14:00 |
| 15:00 | 16:00 |
| 17:00 | 18:00 |
| 19:00 | 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 EDT to AST Time Conversion
Converting time between Eastern Daylight Time (EDT) and Atlantic Standard Time (AST) is essential for coordinating between the US East Coast and Atlantic Canada. EDT is UTC-4 (used March to November), while AST is UTC-4 year-round. However, Atlantic Canada observes Atlantic Daylight Time (ADT, UTC-3) from March to November, making the effective difference 1 hour when EDT is active. This conversion bridges major US population centers and Canadian Atlantic provinces.
This converter is valuable for business operations, travel planning, and personal coordination between Eastern US cities (New York, Boston, Philadelphia) and Atlantic Canadian cities (Halifax, Saint John, Charlottetown). The 1-hour difference creates favorable overlap for business coordination between these regions, especially during the summer months when both regions are observing daylight saving time variants.
Common Use Cases for EDT to AST Conversion
Business & Work
- Scheduling meetings between East Coast US offices and Atlantic Canada operations
- Coordinating with Atlantic Canada business partners and clients
- Planning conference calls across Eastern US and Atlantic Canadian time zones
- Managing cross-border business operations between regions
- Coordinating summer tourism and hospitality industry operations
Personal & Travel
- Coordinating with family and friends in Atlantic Canada (Nova Scotia, New Brunswick, PEI)
- Planning travel to Atlantic Canada destinations during summer
- Scheduling events that include participants from both regions
- Understanding time differences for communications with Canadian contacts
- Managing summer vacation planning across the US-Canada border
Time Zone Information
Eastern Daylight Time (EDT)
- UTC Offset: UTC-4 (UTC-5 during EST)
- IANA Timezone: America/New_York
- Daylight Saving: Second Sunday in March to First Sunday in November
- Major Cities: New York, Boston, Philadelphia, Atlanta, Miami, Washington DC
- Coverage: Eastern United States and Eastern Canada
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
- Major Cities: Halifax, Saint John, Charlottetown, St. John's, Moncton
- Coverage: Atlantic Canada and some Caribbean islands
Quick Reference: EDT to AST
Note: During summer (March-November), Atlantic Canada uses ADT (UTC-3), making it 1 hour ahead of EDT. During winter, AST (UTC-4) equals EDT offset.
Frequently Asked Questions
What is the time difference between EDT and AST/ADT?
Eastern Daylight Time (EDT) is UTC-4. Atlantic Standard Time (AST) is UTC-4, but Atlantic Canada observes Atlantic Daylight Time (ADT, UTC-3) from March to November. During summer (when EDT is active), ADT is 1 hour ahead of EDT. When it's 12:00 PM in New York (EDT), it's 1:00 PM in Halifax (ADT).
Why is the EDT-AST difference important?
Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island) is a major business hub and travel destination for US East Coast residents. The minimal 1-hour difference makes coordination practical, unlike the larger offsets with West Coast regions. This difference is crucial for shipping/logistics, tourism, and cross-border business operations.
When do EDT and ADT transition dates occur?
EDT runs from the second Sunday in March to the first Sunday in November. ADT runs on the exact same schedule. This means the 1-hour difference is consistent throughout the entire daylight saving period. During winter, both regions shift to standard times (EST and AST), maintaining the same relative offset.
What are the best times to schedule calls between EDT and AST zones?
Optimal meeting windows: 9-11 AM EDT (10 AM-12 PM ADT), 11 AM-1 PM EDT (12-2 PM ADT), 2-4 PM EDT (3-5 PM ADT). The sweet spot is 10 AM-12 PM EDT (11 AM-1 PM ADT) when both regions are in productive morning/noon hours. Avoid early mornings before 8 AM EDT (9 AM ADT).
Why do businesses coordinate between EDT and Atlantic Canada?
Major reasons: shipping/logistics hubs in Halifax, tourism operations in Nova Scotia/PEI, financial services, tech companies, media, call centers, and manufacturing. Atlantic Canada has significant economic importance for US East Coast operations, making timezone coordination essential for daily business.
How do summer and winter transitions affect EDT-AST scheduling?
Both EDT and ADT/AST follow the same transition schedule (March and November), so the 1-hour difference remains constant year-round. This means you can maintain the same meeting times throughout the year without adjustment - a major advantage over other transatlantic or coast-to-coast conversions.
Pro Tips
- • Use "10 AM ET / 11 AM AT" format when scheduling calls - this double notation prevents confusion. AT represents Atlantic Time (either ADT or AST depending on season).
- • The 1-hour difference is minimal and favorable. A 10 AM EDT meeting is 11 AM ADT - both regions are in productive morning hours with no extreme inconvenience.
- • Best coordination window: 10 AM-12 PM EDT (11 AM-1 PM ADT) captures optimal productivity for both regions without sacrificing work-life balance.
- • Both regions transition on the exact same dates (March and November), so you can maintain consistent meeting times year-round without adjustment.
- • For US-Canada cross-border operations, remember Atlantic Canada is 1 hour ahead during summer months. Update team calendars and communication tools with this timezone pairing.
- • Schedule routine meetings during the overlap window: 8 AM-3 PM EDT (9 AM-4 PM ADT) captures full business hours for both regions.
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