AST to China
+12hAST
ASTSOURCEChina
CSTGreen rows indicate typical business hours (9 AM - 5 PM)
AST and CST on the World Map
The map below highlights the AST (Atlantic Standard Time) and CST (China Standard Time) timezone regions across the globe.
AST – Atlantic Standard Time
UTC-04:00Atlantic Standard Time (AST) is the time zone for the Canadian Atlantic provinces and the Caribbean, 4 hours behind UTC.
- •Puerto Rico uses AST year-round and does not observe DST.
- •AST is 1 hour ahead of EST.
- •Halifax, the capital of Nova Scotia, is the largest city in AST Canada.
CST – China Standard Time
UTC+08:00China Standard Time (CST) covers all of mainland China, 8 hours ahead of UTC.
- •China uses a single time zone despite spanning 5 geographical zones.
- •In Xinjiang (western China), sunset can be as late as midnight in summer.
- •China abolished daylight saving time in 1991.
- •The Shanghai Stock Exchange operates on CST/Beijing Time.
Everything You Need to Know About AST and China Time
AST runs on Atlantic Standard Time (AST) at UTC-04:00. China runs on China Standard Time (CST) at UTC+08:00. That puts AST 12 hours ahead of China — a difference of +12h at the current offsets.
In practice, when it is 9:00 AM in AST it is 9:00 PM in China. Midnight in AST is 12:00 PM in China. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AST to China time conversion table
| AST (AST) | China (CST) | Day |
|---|---|---|
| 12:00 AM | 12:00 PM | same day |
| 6:00 AM | 6:00 PM | same day |
| 7:00 AM | 7:00 PM | same day |
| 8:00 AM | 8:00 PM | same day |
| 9:00 AM | 9:00 PM | same day |
| 12:00 PM | 12:00 AM | next day |
| 3:00 PM | 3:00 AM | next day |
| 5:00 PM | 5:00 AM | next day |
| 6:00 PM | 6:00 AM | next day |
| 9:00 PM | 9:00 AM | next day |
Why people convert AST to China time
- Scheduling a call from AST to China: a 10:00 AM start in AST lands at 10:00 PM in China, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +12h gap: AST and China have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in China is 9:00 PM in AST.
- Booking travel or deliveries: tracking China local time against AST keeps pickup windows and arrival estimates honest across the +12h offset.
- Always state the zone abbreviation, not just the hour. "3:00 PM AST" is unambiguous; "3 PM" across a +12h gap is not.
- With a +12h gap there is no shared 9-to-5 window, so alternate the early start: one week AST takes the early slot, the next week China does.
About AST (Atlantic Standard Time)
Atlantic Standard Time (AST) covers Canada's Atlantic provinces (Nova Scotia, New Brunswick, Prince Edward Island, and most of Labrador), as well as several Caribbean nations. Puerto Rico and the US Virgin Islands use AST year-round without daylight saving time. The Canadian provinces switch to Atlantic Daylight Time (ADT) in summer.
About CST (China Standard Time)
China Standard Time (CST, also known as Beijing Time) is used across all of mainland China despite the country spanning five geographical time zones. This single-timezone policy was adopted in 1949. China does not observe daylight saving time. CST is shared with Hong Kong (HKT), Macau, Taiwan, Singapore, Malaysia, and the Philippines, making UTC+08:00 one of the most used offsets in the world.
Best time to call between AST and China
With a +12h offset there is no overlap inside a normal 9 AM – 5 PM day. China opens at 9:00 AM CST, which is 9:00 PM in AST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
AST and China have no shared working hours because of the +12h gap. Teams need to alternate early starts or rely on asynchronous handovers.
AST is 12 hours ahead of China (AST UTC-04:00 → CST UTC+08:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
AST
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
China
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between AST and China?
AST (AST, UTC-04:00) is 12 hours ahead of China (CST, UTC+08:00). The gap is currently +12h.
How do I convert AST time to China time?
Add +12h to AST local time. For example, 9:00 AM in AST is 9:00 PM in China.
What time is it in China right now?
China uses CST at UTC+08:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +12h offset from AST.
What is the best time to call China from AST?
There is no shared working-hours window because of the +12h gap. The closest option is 1:00 PM in AST, which is 1:00 AM in China.
Which is ahead, AST or China?
AST is 12 hours ahead of China. When it is 12:00 PM in AST it is 12:00 AM in China.
Do AST and China use different time zones?
AST uses AST at UTC-04:00, while China (China) uses CST at UTC+08:00. The IANA identifiers are America/Halifax and Asia/Shanghai.
Does daylight saving time affect the AST–China difference?
Neither zone observes daylight saving time, so the +12h offset between AST and China is fixed all year.
Which other cities share AST's time zone?
AST also covers Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
Which countries use AST, AST's zone?
AST is used in Canada (Atlantic provinces), Puerto Rico, US Virgin Islands, Dominican Republic, Venezuela, Bolivia, Barbados, Trinidad and Tobago.
Is there a day difference between AST and China?
Sometimes. The +12h gap is large enough that 8:00 PM or later in AST already falls on the next day in China.
What is the time difference between AST and China?
China is +12h from AST.
What timezone is AST in?
AST operates on its local timezone.
What timezone is China in?
China operates on its local timezone.
Which countries use AST (Atlantic Standard Time)?
AST is used in Canada (Atlantic provinces), Puerto Rico, US Virgin Islands, Dominican Republic, Venezuela, Bolivia, and 2 more countries.
Does AST observe daylight saving time?
Yes, AST switches to ADT during summer months.
What are some interesting facts about AST?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
Which cities are in the CST timezone?
Major cities in the CST timezone include Shanghai, Beijing, Shenzhen, Guangzhou, Chengdu, Hong Kong, Taipei, Wuhan.
What is the UTC offset for CST?
China Standard Time (CST) is at UTC+08:00.
What should I know about the CST timezone?
China uses a single time zone despite spanning 5 geographical zones. In Xinjiang (western China), sunset can be as late as midnight in summer.
When is it midnight in AST, what time is it in China?
When it is 12:00 AM (midnight) in AST (AST), it is +12h later in China (CST).
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See every conversion from AST →·See every conversion from China →