AST to PST Converter
Convert time between Atlantic Standard Time (AST) and Pacific Standard Time (PST)
Atlantic Standard Time (AST)
Pacific Standard Time (PST)
Time Difference
Pacific Standard Time (PST) is 0 hours ahead of Atlantic Standard Time (AST)
Select Date
Select Time
Quick Reference
| AST | PST |
|---|---|
| 22:00 | 18:00 |
| 00:00 | 20:00 |
| 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 |
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 PST Time Conversion
Converting time between Atlantic Standard Time (AST) and Pacific Standard Time (PST) is essential for coordinating across North America's coasts. AST is UTC-4 and is used in Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island, and parts of Newfoundland and Labrador), while PST is UTC-8 and is used across the Pacific United States and Canada (November to March). AST is 4 hours ahead of PST.
This conversion is crucial for business coordination between Atlantic Canada and the US West Coast, travel planning, and communication across these distant regions. Understanding the 4-hour time difference helps ensure accurate scheduling for business meetings, family calls, and coordinated activities spanning both coasts of North America.
Common Use Cases for AST to PST Conversion
Business & Work
- Scheduling meetings between Atlantic Canada and Pacific West Coast offices
- Coordinating with Pacific Coast business partners and clients
- Planning conference calls across the Atlantic and Pacific time zones
- Managing distributed teams across North American coasts
Personal & Travel
- Coordinating with family and friends in Pacific Coast regions
- Planning travel from Atlantic Canada to Pacific Coast destinations
- Scheduling events that include participants from both regions
- Understanding time differences for remote communications
Time Zone Information
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, Fredericton
- Coverage: Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island)
Pacific Standard Time (PST)
- UTC Offset: UTC-8 (UTC-7 during PDT)
- IANA Timezone: America/Los_Angeles
- Daylight Saving: Second Sunday in March to First Sunday in November
- Major Cities: Los Angeles, San Francisco, Seattle, San Diego, Portland, Vancouver
- Coverage: Pacific United States and Canada
Quick Reference: AST to PST
Remember: AST is always 4 hours ahead of PST
Frequently Asked Questions
What is the time difference between AST and PST?
Atlantic Standard Time (AST) is UTC-4, while Pacific Standard Time (PST) is UTC-8. This means AST is 4 hours ahead of PST. When it's 12:00 PM (noon) in Halifax (AST), it's 8:00 AM in Los Angeles (PST). Note: AST is also used for Atlantic Daylight Time (ADT, UTC-3) during daylight saving time.
How does AST to PST differ from other timezone conversions?
The 4-hour offset between AST and PST is straightforward compared to many other conversions. This makes scheduling between Atlantic Canada (Halifax, St. John's area) and the US Pacific coast relatively manageable. The offset remains consistent even during daylight saving time transitions, though the naming changes (AST/ADT vs PST/PDT).
Does Newfoundland use AST like other Atlantic provinces?
Newfoundland and Labrador use Newfoundland Standard Time (NST, UTC-3:30) and Newfoundland Daylight Time (NDT, UTC-2:30), which differ from Atlantic Standard Time. This makes Newfoundland 30 minutes ahead of other Atlantic provinces, adding complexity to Atlantic region scheduling. Always verify which timezone applies when coordinating with Newfoundland.
When do AST and PST change for daylight saving time?
Both AST and PST transition to daylight saving time (ADT and PDT) on the second Sunday in March and transition back on the first Sunday in November. During these transition periods, the offset remains 4 hours, but the timezone abbreviations change. Always update your calendar systems during these transitions.
What are the best times to schedule calls between Atlantic Canada and the US Pacific?
Business hour overlap is significant with a 4-hour offset. Atlantic morning (9 AM-12 PM AST) overlaps with Pacific early morning (5 AM-8 AM PST). Pacific afternoon (2 PM-5 PM PST) overlaps with Atlantic evening (6 PM-9 PM AST). The 9 AM-12 PM AST window offers the best balance for both regions during typical business hours.
Why is AST important for Canadian-US West Coast coordination?
Atlantic Standard Time is the standard for Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island), making it essential for coordinating between Eastern Canada and the US Pacific region. With a 4-hour difference, it's easier to find common business hours compared to Central or Mountain time zones. This makes the Atlantic-Pacific route favorable for cross-country projects.
Pro Tips
- • The 4-hour offset is easy to remember: subtract 4 hours from AST to get PST. A 3 PM AST call is 11 AM PST.
- • Both regions transition to daylight saving on the same dates (second Sunday in March, first Sunday in November). Mark these dates to adjust meeting schedules.
- • Early morning Atlantic meetings (9-10 AM AST) are ideal for Pacific West Coast teams starting their day (5-6 AM PST).
- • Late afternoon Pacific calls (4-5 PM PST) work perfectly for Atlantic teams in their early evening (8-9 PM AST) after typical business hours.
- • Watch for Newfoundland exceptions - they are 30 minutes ahead of Atlantic provinces, affecting any coordinated Atlantic region scheduling.
- • Document all meeting times in both AST and PST, including whether daylight saving time is currently active, to prevent confusion during transitions.
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