AST to CST Converter
Convert time between Atlantic Standard Time (AST) and Central Standard Time (CST)
Atlantic Standard Time (AST)
Central Standard Time (CST)
Time Difference
Central Standard Time (CST) is 0 hours ahead of Atlantic Standard Time (AST)
Select Date
Select Time
Quick Reference
| AST | CST |
|---|---|
| 22:00 | 20:00 |
| 00:00 | 22:00 |
| 02:00 | 00:00 |
| 04:00 | 02:00 |
| 06:00 | 04:00 |
| 08:00 | 06:00 |
| 10:00 | 08:00 |
| 12:00 | 10:00 |
| 14:00 | 12:00 |
| 16:00 | 14:00 |
| 18:00 | 16:00 |
| 20:00 | 18:00 |
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 CST Time Conversion
Converting time between Atlantic Standard Time (AST) and Central Standard Time (CST) is essential for coordinating between Atlantic Canada and the US Central region. AST is UTC-4 (the standard time in Atlantic Canada, used November to March), while CST is UTC-6 (standard time on the US Central, typically November to March). AST is 2 hours ahead of CST, making it the smallest time difference among Atlantic-US region conversions.
This conversion is crucial for business coordination between Atlantic Canada and the US Central region, home to major business hubs like Chicago, Dallas, Houston, and other significant economic centers. The minimal 2-hour time difference provides excellent business hour overlap compared to Atlantic-Pacific coordination. When daylight saving time transitions occur (second Sunday in March and first Sunday in November), both regions shift simultaneously, with the time difference reducing to just 1 hour (ADT to CDT). Understanding this favorable timezone relationship makes Central region coordination an attractive option for Atlantic Canadian businesses.
Common Use Cases for AST to CST Conversion
Business & Work
- Scheduling meetings between Atlantic Canada and Central region offices
- Coordinating software development teams across Atlantic and Central zones
- Managing business operations with Central region partners and clients
- Planning conference calls and project deadlines across regions
Personal & Travel
- Coordinating with family and friends in the Central region
- Planning travel from Atlantic Canada to Central destinations
- Scheduling virtual meetings with Central region relatives
- Arranging online collaboration with Central region-based colleagues
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)
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, St. Louis
- Coverage: Central United States and Canada (winter months)
Quick Reference: AST to CST
Remember: AST is 2 hours ahead of CST during winter (November-March). From March to November when ADT and CDT are active, the difference becomes 1 hour (ADT to CDT).
Frequently Asked Questions
What is the time difference between AST and CST?
Atlantic Standard Time (AST) is UTC-4, while Central Standard Time (CST) is UTC-6. This means AST is 2 hours ahead of CST. When it's 12:00 PM (noon) in Halifax (AST), it's 10:00 AM in Chicago (CST). Note: This 2-hour difference applies during winter months (November to March) when both regions observe standard time. From March to November, when Central Daylight Time (CDT, UTC-5) is active, the difference becomes 1 hour.
How does the AST to CST offset differ from other Atlantic-US conversions?
The 2-hour offset between AST and CST is the smallest difference among Atlantic-US conversions, making Atlantic-Central coordination the most manageable. Compared to AST-MST (3 hours) or AST-PST (4 hours), the 2-hour gap provides better business hour overlap. Both regions transition to daylight time on the same schedule (second Sunday in March, first Sunday in November), which simplifies calendar management. The minimal time difference makes the Central region an ideal choice for coordinating with Atlantic Canada.
Does the Central region observe daylight saving time like Atlantic Canada?
Yes, both regions observe daylight saving time on the same dates (second Sunday in March to first Sunday in November). Atlantic Canada transitions from AST (UTC-4) to Atlantic Daylight Time (ADT, UTC-3), while the Central region transitions from CST (UTC-6) to Central Daylight Time (CDT, UTC-5). This reduces the time difference from 2 hours (AST-CST) to 1 hour (ADT-CDT). From November to March, both regions maintain their standard time with the full 2-hour difference.
When does the time difference change from 2 to 1 hour?
The difference changes on the second Sunday in March when both regions simultaneously transition to daylight saving time. From March to November, the difference is 1 hour (ADT to CDT). From November to March, the difference is 2 hours (AST to CST). Both regions use identical transition dates, making it simple to remember and update your meeting schedules. Mark these dates: second Sunday in March (spring forward) and first Sunday in November (fall back).
What are the best times to schedule calls between Atlantic Canada and Central region?
Business hour overlap is excellent with a 2-hour difference (winter) or 1-hour difference (summer). Atlantic morning (9 AM-12 PM AST) overlaps perfectly with Central morning (7 AM-10 AM CST), offering significant overlap. For afternoon calls, 2 PM-4 PM CST (3 PM-5 PM AST) provides late morning/early afternoon availability for both regions. With only a 2-hour gap, you can often find meeting times during standard business hours (9 AM-5 PM) in both locations. The 10 AM-12 PM AST window (8 AM-10 AM CST) provides excellent morning alignment.
Why is the Central region ideal for Atlantic Canada coordination?
The Central region offers the best combination of factors for Atlantic Canada coordination: the smallest time difference (2 hours, becoming 1 hour in summer), major business hubs like Chicago, Dallas, and Houston with significant corporate headquarters and tech presence, and excellent flight connections from Atlantic Canadian cities. Many Canadian companies prefer Central region partnerships because the time zone is manageable while accessing major US markets. The minimal timezone difference reduces scheduling complexity and allows for better real-time communication compared to West or East Coast coordination.
Pro Tips
- • Remember the 2-hour offset (winter) or 1-hour offset (summer). The difference changes only on daylight saving transition dates (second Sunday in March and first Sunday in November).
- • Both regions transition to daylight saving on the same dates. This means your meeting times only need one adjustment per year instead of multiple changes.
- • Schedule Atlantic team morning meetings (9-10 AM AST) to match Central team morning (7-8 AM CST) - this creates excellent alignment for early-morning discussions or standup meetings.
- • The 10 AM-4 PM CST window (11 AM-5 PM AST) offers near-complete overlap with standard business hours in both regions, making it ideal for collaborative work.
- • During summer (ADT-CDT, 1-hour difference), the time zones are nearly aligned, making scheduling even simpler. A 9 AM AST call is only 8 AM CDT.
- • Document all meeting times in both AST and CST to prevent scheduling errors, and update immediately after daylight saving transitions to maintain consistency.
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