GST to AST
-8hGST
GSTSOURCEAST
ASTGreen rows indicate typical business hours (9 AM - 5 PM)
GST and AST on the World Map
The map below highlights the GST (Gulf Standard Time) and AST (Atlantic Standard Time) timezone regions across the globe.
GST – Gulf Standard Time
UTC+04:00Gulf Standard Time (GST) is used in the UAE, Oman, and other Gulf states, 4 hours ahead of UTC.
- •Dubai uses GST year-round with no daylight saving time.
- •GST is 9 hours ahead of EST and 4 hours ahead of GMT.
- •The Dubai Financial Market (DFM) operates on GST.
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.
Time Conversion Guide: GST to AST
GST runs on Gulf Standard Time (GST) at UTC+04:00. AST runs on Atlantic Standard Time (AST) at UTC-04:00. That puts GST 8 hours behind AST — a difference of -8h at the current offsets.
In practice, when it is 9:00 AM in GST it is 1:00 AM in AST. Midnight in GST is 4:00 PM in AST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
GST to AST time conversion table
| GST (GST) | AST (AST) | Day |
|---|---|---|
| 12:00 AM | 4:00 PM | previous day |
| 6:00 AM | 10:00 PM | previous day |
| 7:00 AM | 11:00 PM | previous day |
| 8:00 AM | 12:00 AM | same day |
| 9:00 AM | 1:00 AM | same day |
| 12:00 PM | 4:00 AM | same day |
| 3:00 PM | 7:00 AM | same day |
| 5:00 PM | 9:00 AM | same day |
| 6:00 PM | 10:00 AM | same day |
| 9:00 PM | 1:00 PM | same day |
Why people convert GST to AST time
- Scheduling a call from GST to AST: a 10:00 AM start in GST lands at 2:00 AM in AST, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -8h gap: GST and AST 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 AST is 1:00 AM in GST.
- Watching a live event or market open: GST viewers need 1:00 AM in AST to catch a 9:00 AM start there, and 8:00 AM if the event is anchored to GST.
- Always state the zone abbreviation, not just the hour. "3:00 PM GST" is unambiguous; "3 PM" across a -8h gap is not.
- With a -8h gap there is no shared 9-to-5 window, so alternate the early start: one week GST takes the early slot, the next week AST does.
About GST (Gulf Standard Time)
Gulf Standard Time (GST) is the time zone used in the United Arab Emirates, Oman, and other Gulf states. GST does not observe daylight saving time. Dubai and Abu Dhabi, major international business and tourism hubs, operate on GST.
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.
Best time to call between GST and AST
With a -8h offset there is no overlap inside a normal 9 AM – 5 PM day. AST opens at 9:00 AM AST, which is 1:00 AM in GST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
GST and AST have no shared working hours because of the -8h gap. Teams need to alternate early starts or rely on asynchronous handovers.
GST is 8 hours behind AST (GST UTC+04:00 → AST UTC-04:00). 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
GST
Does not observe DST
AST
☀ Currently in DST
Standard: UTC-04:00 · DST: UTC-03:00
Clocks fall back on Sun, Nov 1, 2026
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 GST and AST?
GST (GST, UTC+04:00) is 8 hours behind AST (AST, UTC-04:00). The gap is currently -8h.
How do I convert GST time to AST time?
Add -8h to GST local time. For example, 9:00 AM in GST is 1:00 AM in AST.
What time is it in AST right now?
AST uses AST at UTC-04:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -8h offset from GST.
What is the best time to call AST from GST?
There is no shared working-hours window because of the -8h gap. The closest option is 1:00 PM in GST, which is 5:00 AM in AST.
Which is behind, GST or AST?
GST is 8 hours behind AST. When it is 12:00 PM in GST it is 4:00 AM in AST.
Does daylight saving time affect the GST–AST difference?
Neither zone observes daylight saving time, so the -8h offset between GST and AST is fixed all year.
Which other cities share GST's time zone?
GST also covers Dubai, Abu Dhabi, Muscat, Baku, Tbilisi.
Which countries use GST, GST's zone?
GST is used in UAE, Oman, Georgia, Azerbaijan, Mauritius.
Is there a day difference between GST and AST?
Not normally. The -8h gap only pushes the date over the previous day.
What is the time difference between GST and AST?
AST is -8h from GST.
What timezone is GST in?
GST operates on its local timezone.
What timezone is AST in?
AST operates on its local timezone.
Which countries use GST (Gulf Standard Time)?
GST is used in UAE, Oman, Georgia, Azerbaijan, Mauritius.
Does GST observe daylight saving time?
No, GST does not observe daylight saving time and remains at UTC+04:00 year-round.
What are some interesting facts about GST?
Dubai uses GST year-round with no daylight saving time. GST is 9 hours ahead of EST and 4 hours ahead of GMT.
Which cities are in the AST timezone?
Major cities in the AST timezone include Halifax, San Juan, Santo Domingo, Caracas, La Paz, Fredericton, Charlottetown.
What is the UTC offset for AST?
Atlantic Standard Time (AST) is at UTC-04:00. During daylight saving time, it shifts to ADT.
What should I know about the AST timezone?
Puerto Rico uses AST year-round and does not observe DST. AST is 1 hour ahead of EST.
When is it midnight in GST, what time is it in AST?
When it is 12:00 AM (midnight) in GST (GST), it is -8h later in AST (AST).
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