CST to AST Converter
Convert time between Central Standard Time (CST) and Atlantic Standard Time (AST)
Central Standard Time (CST)
Atlantic Standard Time (AST)
Time Difference
Atlantic Standard Time (AST) is 0 hours ahead of Central Standard Time (CST)
Select Date
Select Time
Quick Reference
| CST | AST |
|---|---|
| 20:00 | 22:00 |
| 22:00 | 00:00 |
| 00:00 | 02:00 |
| 02:00 | 04:00 |
| 04:00 | 06:00 |
| 06:00 | 08:00 |
| 08:00 | 10:00 |
| 10:00 | 12:00 |
| 12:00 | 14:00 |
| 14:00 | 16:00 |
| 16:00 | 18:00 |
| 18:00 | 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 CST to AST Time Conversion
Central Standard Time (CST) is UTC-6 and is used across the central United States and parts of Canada and Mexico. Atlantic Standard Time (AST) is UTC-4 and is used in Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island, and parts of Newfoundland and Labrador) as well as some Caribbean islands. AST is 2 hours ahead of CST.
This conversion is essential for business coordination between central North America and Atlantic Canada, as well as for travel planning and communication across these regions. Understanding the time difference helps ensure accurate scheduling for business meetings, family calls, and coordinated activities.
Common Use Cases for CST to AST Conversion
Business & Work
- Scheduling meetings between central US offices and Atlantic Canada operations
- Coordinating with Atlantic Canada business partners and clients
- Planning conference calls across the Central and Atlantic time zones
Personal & Travel
- Coordinating with family and friends in Atlantic Canada
- Planning travel to Nova Scotia, New Brunswick, or Prince Edward Island
- Scheduling events that include participants from both regions
Time Zone Information
Central Standard Time (CST)
- UTC Offset: UTC-6 (UTC-5 during CDT)
- IANA Timezone: America/Chicago
- Daylight Saving: Second Sunday in March to First Sunday in November
- Major Cities: Chicago, Dallas, Houston, Kansas City, New Orleans
- Coverage: Central United States and parts of Canada and Mexico
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
- Coverage: Atlantic Canada and some Caribbean islands
Quick Reference: CST to AST
Remember: AST is always 2 hours ahead of CST
Frequently Asked Questions
What is the time difference between CST and AST?
Central Standard Time (CST) is UTC-6, while Atlantic Standard Time (AST) is UTC-4. This means AST is 2 hours ahead of CST. When it's 10:00 AM in Chicago (CST), it's 12:00 PM (noon) in Halifax (AST).
What is Atlantic Standard Time (AST)?
Atlantic Standard Time (AST) is UTC-4 and is observed in Atlantic Canada (Nova Scotia, New Brunswick, Prince Edward Island, and parts of Newfoundland and Labrador) and some Caribbean islands. During daylight saving time (March-November), it becomes Atlantic Daylight Time (ADT, UTC-3). AST is 1 hour ahead of EST and EDT depending on the season.
Do CST and AST have daylight saving transitions on the same dates?
Yes, both CST and AST observe daylight saving time on the same dates. CST transitions to CDT on the second Sunday in March, and AST transitions to ADT on the same date. Both transition back on the first Sunday in November. This means the 2-hour difference remains consistent year-round.
What are the best times to schedule meetings between CST and AST regions?
Since AST is 2 hours ahead, there is good business hour overlap. Morning meetings in the Central region (10-11 AM CST) align with noon-1 PM in Atlantic Canada (AST). Afternoon Central time (2-3 PM CST) works well as 4-5 PM Atlantic time (AST). These windows provide optimal coordination for both regions.
Which major cities are in Atlantic Canada (AST)?
Major AST cities include Halifax (Nova Scotia), Saint John (New Brunswick), Charlottetown (Prince Edward Island), and St. John's (Newfoundland and Labrador). These Atlantic Canadian cities are important business centers, tourism destinations, and cultural hubs, making CST to AST conversion relevant for travel, business, and personal connections.
Why would I need to convert CST to AST?
CST to AST conversion is useful for business coordination with Atlantic Canada, scheduling calls with family or friends in the Atlantic provinces, planning travel to Nova Scotia, New Brunswick, or Prince Edward Island, and coordinating events that involve participants from both the central US and Atlantic Canada regions.
Pro Tips
- • Remember: AST is always 2 hours ahead of CST. A quick way to convert is to add 2 hours to CST to get AST.
- • The best meeting window is 10 AM-3 PM CST, which converts to 12 PM-5 PM AST - covering business hours in both regions.
- • Both CST and AST observe daylight saving on the same dates, so the 2-hour offset remains constant throughout the year.
- • When traveling to Atlantic Canada, remember that Halifax and other AST cities are 2 hours ahead - set your watch forward when you arrive.
- • For international business coordination, note that AST also impacts communication with Caribbean islands that observe the same timezone.
- • Use this converter for scheduling meetings, planning travel, and coordinating events with Atlantic Canada and US Central region participants.
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