ICT to Tehran
-3h 30mICT
ICTSOURCETehran
IRSTGreen rows indicate typical business hours (9 AM - 5 PM)
ICT and IRST on the World Map
The map below highlights the ICT (Indochina Time) and IRST (Iran Standard Time) timezone regions across the globe.
ICT – Indochina Time
UTC+07:00Indochina Time (ICT) is the time zone for Vietnam, Thailand, Laos, and Cambodia, 7 hours ahead of UTC.
- •Bangkok is one of the most visited cities in the world.
- •ICT is 12 hours ahead of EST.
- •Thailand, Vietnam, and Cambodia all share ICT.
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).
Understanding the -3h 30m Gap: ICT vs Tehran
ICT runs on Indochina Time (ICT) at UTC+07:00. Tehran runs on Iran Standard Time (IRST) at UTC+03:30. That puts ICT 3 hours 30 minutes behind Tehran — a difference of -3h 30m at the current offsets.
In practice, when it is 9:00 AM in ICT it is 5:30 AM in Tehran. Midnight in ICT is 8:30 PM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.
ICT to Tehran time conversion table
| ICT (ICT) | Tehran (IRST) | Day |
|---|---|---|
| 12:00 AM | 8:30 PM | previous day |
| 6:00 AM | 2:30 AM | same day |
| 7:00 AM | 3:30 AM | same day |
| 8:00 AM | 4:30 AM | same day |
| 9:00 AM | 5:30 AM | same day |
| 12:00 PM | 8:30 AM | same day |
| 3:00 PM | 11:30 AM | same day |
| 5:00 PM | 1:30 PM | same day |
| 6:00 PM | 2:30 PM | same day |
| 9:00 PM | 5:30 PM | same day |
Why people convert ICT to Tehran time
- Scheduling a call from ICT to Tehran: a 10:00 AM start in ICT lands at 6:30 AM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both ICT and Tehran are inside the 9-to-5 working day between 12:30 PM and 5:00 PM ICT time (9:00 AM–1:30 PM IRST). That is roughly 4 hours 30 minutes of usable overlap.
- Keeping family and friends in sync: knowing that 8:00 PM in ICT is 4:30 PM in Tehran makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM ICT" is unambiguous; "3 PM" across a -3h 30m gap is not.
- Block 12:30 PM–5:00 PM ICT as the recurring meeting window if you work primarily from ICT and need Tehran colleagues present.
About ICT (Indochina Time)
Indochina Time (ICT) is used across Southeast Asia including Vietnam, Thailand, Laos, and Cambodia. Indonesia (Western time, WIB) also uses UTC+07:00. ICT does not observe daylight saving time.
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 ICT and Tehran
Both ICT and Tehran sit inside the 9 AM – 5 PM working day between 12:30 PM–5:00 PM ICT, which is 9:00 AM–1:30 PM IRST. That gives roughly 4 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
ICT and Tehran overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.
ICT is 3 hours 30 minutes behind Tehran (ICT UTC+07:00 → IRST UTC+03:30). The shared working window is 12:30 PM–5:00 PM ICT. Remember to re-check around daylight-saving transitions.
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 ICT and Tehran?
ICT (ICT, UTC+07:00) is 3 hours 30 minutes behind Tehran (IRST, UTC+03:30). The gap is currently -3h 30m.
How do I convert ICT time to Tehran time?
Add -3h 30m to ICT local time. For example, 9:00 AM in ICT is 5:30 AM 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 -3h 30m offset from ICT.
What is the best time to call Tehran from ICT?
Call between 12:30 PM and 5:00 PM ICT — that maps to 9:00 AM–1:30 PM IRST and keeps both parties inside the working day.
Which is behind, ICT or Tehran?
ICT is 3 hours 30 minutes behind Tehran. When it is 12:00 PM in ICT it is 8:30 AM in Tehran.
Do ICT and Tehran use different time zones?
ICT uses ICT at UTC+07:00, while Tehran (Iran) uses IRST at UTC+03:30. The IANA identifiers are Asia/Bangkok and Asia/Tehran.
Does daylight saving time affect the ICT–Tehran difference?
Neither zone observes daylight saving time, so the -3h 30m offset between ICT and Tehran is fixed all year.
Which other cities share ICT's time zone?
ICT also covers Bangkok, Ho Chi Minh City, Hanoi, Jakarta, Phnom Penh, Vientiane.
Which countries use ICT, ICT's zone?
ICT is used in Thailand, Vietnam, Cambodia, Laos, Indonesia (WIB).
Is there a day difference between ICT and Tehran?
Not normally. The -3h 30m gap only pushes the date over the previous day.
What is the time difference between ICT and Tehran?
Tehran is -3h 30m from ICT.
What timezone is ICT in?
ICT 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 ICT (Indochina Time)?
ICT is used in Thailand, Vietnam, Cambodia, Laos, Indonesia (WIB).
Does ICT observe daylight saving time?
No, ICT does not observe daylight saving time and remains at UTC+07:00 year-round.
What are some interesting facts about ICT?
Bangkok is one of the most visited cities in the world. ICT is 12 hours 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 ICT, what time is it in Tehran?
When it is 12:00 AM (midnight) in ICT (ICT), it is -3h 30m later in Tehran (IRST).
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