AST to Tehran
+7h 30mAST
ASTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
AST and IRST on the World Map
The map below highlights the AST (Atlantic Standard Time) and IRST (Iran 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.
IRST – Iran Standard Time
UTC+03:30Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.
- •IRST is one of only a few time zones with a 30-minute offset.
- •Iran observes daylight saving time, switching to IRDT (UTC+04:30).
- •Tehran has a metropolitan population of over 16 million.
About Tehran
WikipediaTehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).
AST vs Tehran: Offsets, DST and Best Call Times
AST runs on Atlantic Standard Time (AST) at UTC-04:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts AST 7 hours 30 minutes ahead of Tehran — a difference of +7h 30m at the current offsets.
In practice, when it is 9:00 AM in AST it is 4:30 PM in Tehran. Midnight in AST is 7:30 AM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
AST to Tehran time conversion table
| AST (AST) | Tehran (IRST) | Day |
|---|---|---|
| 12:00 AM | 7:30 AM | same day |
| 6:00 AM | 1:30 PM | same day |
| 7:00 AM | 2:30 PM | same day |
| 8:00 AM | 3:30 PM | same day |
| 9:00 AM | 4:30 PM | same day |
| 12:00 PM | 7:30 PM | same day |
| 3:00 PM | 10:30 PM | same day |
| 5:00 PM | 12:30 AM | next day |
| 6:00 PM | 1:30 AM | next day |
| 9:00 PM | 4:30 AM | next day |
Why people convert AST to Tehran time
- Scheduling a call from AST to Tehran: a 10:00 AM start in AST lands at 5:30 PM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both AST and Tehran are inside the 9-to-5 working day between 9:00 AM and 9:30 AM AST time (4:30 PM–5:00 PM IRST). That is roughly 0 hours 30 minutes of usable overlap.
- Watching a live event or market open: AST viewers need 4:30 PM in Tehran to catch a 9:00 AM start there, and 4:30 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 +7h 30m gap is not.
- Block 9:00 AM–9:30 AM AST as the recurring meeting window if you work primarily from AST and need Tehran colleagues present.
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 IRST (Iran Standard Time)
Iran Standard Time (IRST) is one of the few time zones with a 30-minute offset. Iran observes daylight saving time (IRDT, UTC+04:30) from late March to late September. Tehran, the capital, is one of the largest cities in the Middle East.
Best time to call between AST and Tehran
Both AST and Tehran sit inside the 9 AM – 5 PM working day between 9:00 AM–9:30 AM AST, which is 4:30 PM–5:00 PM IRST. That gives roughly 0 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
AST and Tehran overlap for only 30 minutes (9:00 AM–9:30 AM AST), so meetings have to be booked precisely.
AST is 7 hours 30 minutes ahead of Tehran (AST UTC-04:00 → IRST UTC+03:30). The shared working window is 9:00 AM–9:30 AM AST. 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
Tehran
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 Tehran?
AST (AST, UTC-04:00) is 7 hours 30 minutes ahead of Tehran (IRST, UTC+03:30). The gap is currently +7h 30m.
How do I convert AST time to Tehran time?
Add +7h 30m to AST local time. For example, 9:00 AM in AST is 4:30 PM in Tehran.
What time is it in Tehran right now?
Tehran uses IRST at UTC+03:30. Use the live converter at the top of this page — it updates in real time and already accounts for the +7h 30m offset from AST.
What is the best time to call Tehran from AST?
Call between 9:00 AM and 9:30 AM AST — that maps to 4:30 PM–5:00 PM IRST and keeps both parties inside the working day.
Which is ahead, AST or Tehran?
AST is 7 hours 30 minutes ahead of Tehran. When it is 12:00 PM in AST it is 7:30 PM in Tehran.
Do AST and Tehran use different time zones?
AST uses AST at UTC-04:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are America/Halifax and Asia/Tehran.
Does daylight saving time affect the AST–Tehran difference?
Neither zone observes daylight saving time, so the +7h 30m offset between AST and Tehran 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 Tehran?
Not normally. The +7h 30m gap only pushes the date over for late-evening times.
What is the time difference between AST and Tehran?
Tehran is +7h 30m from AST.
What timezone is AST in?
AST operates on its local timezone.
What timezone is Tehran in?
Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.
What are the business hours in Tehran?
Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.
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 IRST timezone?
Major cities in the IRST timezone include Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.
What is the UTC offset for IRST?
Iran Standard Time (IRST) is at UTC+03:30. During daylight saving time, it shifts to IRDT.
What should I know about the IRST timezone?
IRST is one of only a few time zones with a 30-minute offset. Iran observes daylight saving time, switching to IRDT (UTC+04:30).
When is it midnight in AST, what time is it in Tehran?
When it is 12:00 AM (midnight) in AST (AST), it is +7h 30m later in Tehran (IRST).
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