AST to SGT
+12hAST
ASTSOURCESGT
SGTGreen rows indicate typical business hours (9 AM - 5 PM)
AST and SGT on the World Map
The map below highlights the AST (Atlantic Standard Time) and SGT (Singapore 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.
SGT – Singapore Standard Time
UTC+08:00Singapore Standard Time (SGT) is the time zone for Singapore, 8 hours ahead of UTC.
- •Singapore uses UTC+08:00 despite being at about 104°E longitude (closer to UTC+07:00).
- •Singapore does not observe daylight saving time.
- •The Singapore Exchange (SGX) operates on SGT.
Understanding the +12h Gap: AST vs SGT
AST runs on Atlantic Standard Time (AST) at UTC-04:00. SGT runs on Singapore Standard Time (SGT) at UTC+08:00. That puts AST 12 hours ahead of SGT — a difference of +12h at the current offsets.
In practice, when it is 9:00 AM in AST it is 9:00 PM in SGT. Midnight in AST is 12:00 PM in SGT. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AST to SGT time conversion table
| AST (AST) | SGT (SGT) | 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 SGT time
- Scheduling a call from AST to SGT: a 10:00 AM start in AST lands at 10:00 PM in SGT, so you can confirm the slot without doing the arithmetic yourself.
- Handling a +12h gap: AST and SGT 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 SGT is 9:00 PM in AST.
- Watching a live event or market open: AST viewers need 9:00 PM in SGT to catch a 9:00 AM start there, and 12:00 PM if the event is anchored to AST.
- 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 SGT 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 SGT (Singapore Standard Time)
Singapore Standard Time (SGT) is used in Singapore year-round. Singapore does not observe daylight saving time. Despite being geographically close to the UTC+07:00 zone, Singapore uses UTC+08:00 to align with major trading partners like China, Hong Kong, and Malaysia. Singapore is a major global financial hub.
Best time to call between AST and SGT
With a +12h offset there is no overlap inside a normal 9 AM – 5 PM day. SGT opens at 9:00 AM SGT, 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 SGT 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 SGT (AST UTC-04:00 → SGT 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
SGT
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 SGT?
AST (AST, UTC-04:00) is 12 hours ahead of SGT (SGT, UTC+08:00). The gap is currently +12h.
How do I convert AST time to SGT time?
Add +12h to AST local time. For example, 9:00 AM in AST is 9:00 PM in SGT.
What time is it in SGT right now?
SGT uses SGT 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 SGT 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 SGT.
Which is ahead, AST or SGT?
AST is 12 hours ahead of SGT. When it is 12:00 PM in AST it is 12:00 AM in SGT.
Does daylight saving time affect the AST–SGT difference?
Neither zone observes daylight saving time, so the +12h offset between AST and SGT 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 SGT?
Sometimes. The +12h gap is large enough that 8:00 PM or later in AST already falls on the next day in SGT.
What is the time difference between AST and SGT?
SGT is +12h from AST.
What timezone is AST in?
AST operates on its local timezone.
What timezone is SGT in?
SGT 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 SGT timezone?
Major cities in the SGT timezone include Singapore.
What is the UTC offset for SGT?
Singapore Standard Time (SGT) is at UTC+08:00.
What should I know about the SGT timezone?
Singapore uses UTC+08:00 despite being at about 104°E longitude (closer to UTC+07:00). Singapore does not observe daylight saving time.
When is it midnight in AST, what time is it in SGT?
When it is 12:00 AM (midnight) in AST (AST), it is +12h later in SGT (SGT).
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See every conversion from AST →·See every conversion from SGT →