Does it handle Daylight Saving Time?

Yes, the tool automatically adjusts for Daylight Saving Time based on the specific date you select, ensuring accurate conversions year-round.

Can I add multiple cities?

Yes, you can add as many cities as you need to the dashboard to compare times across your entire global network simultaneously.

Vietnam to IRST

-3h 30m

Vietnam

ICTSOURCE

UTC+07:00

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

IRST

UTC+03:30

HH08

MM30

08:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Vietnam

IRST

12:00 AM

8:30 PM-1

2:00 AM

10:30 PM-1

4:00 AM

12:30 AM

6:00 AM

2:30 AM

8:00 AM

4:30 AM

10:00 AM

6:30 AM

12:00 PM

8:30 AM

2:00 PM

10:30 AM

4:00 PM

12:30 PM

6:00 PM

2:30 PM

8:00 PM

4:30 PM

10:00 PM

6:30 PM

Green 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 Zone

→

IRST Zone

Explore all world timezones interactively →

ICT – Indochina Time

UTC+07:00

Indochina Time (ICT) is the time zone for Vietnam, Thailand, Laos, and Cambodia, 7 hours ahead of UTC.

Countries in ICT

ThailandVietnamCambodiaLaosIndonesia (WIB)

Major Cities in ICT

BangkokHo Chi Minh CityHanoiJakartaPhnom PenhVientiane

Key Facts about ICT

•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.

Daylight Saving:No – UTC+07:00 year-round

Learn more about ICT on Wikipedia

IRST – Iran Standard Time

UTC+03:30

Iran Standard Time (IRST) is the time zone for Iran, 3 hours and 30 minutes ahead of UTC.

Countries in IRST

Iran

Major Cities in IRST

TehranIsfahanMashhadTabrizShirazKaraj

Key Facts about IRST

•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.

Daylight Saving:Yes – switches to IRDT

Learn more about IRST on Wikipedia

Vietnam vs IRST: Offsets, DST and Best Call Times

Vietnam runs on Indochina Time (ICT) at UTC+07:00. IRST runs on Iran Standard Time (IRST) at UTC+03:30. That puts Vietnam 3 hours 30 minutes behind IRST — a difference of -3h 30m at the current offsets.

In practice, when it is 9:00 AM in Vietnam it is 5:30 AM in IRST. Midnight in Vietnam is 8:30 PM in IRST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

Vietnam to IRST time conversion table

Vietnam (ICT)	IRST (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 Vietnam to IRST time

Scheduling a call from Vietnam to IRST: a 10:00 AM start in Vietnam lands at 6:30 AM in IRST, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both Vietnam and IRST 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.
Booking travel or deliveries: tracking IRST local time against Vietnam keeps pickup windows and arrival estimates honest across the -3h 30m offset.

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 Vietnam and need IRST 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 Vietnam and IRST

Both Vietnam and IRST 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

Vietnam and IRST overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.

Vietnam is 3 hours 30 minutes behind IRST (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:

⏳

History of Timekeeping

From sundials to atomic clocks - 5000 years of measuring time

🌍

How Time Zones Work

UTC, offsets, and why zones don't follow straight lines

☀️

Daylight Saving Time

DST dates, which countries observe it, and the ongoing debate

Frequently Asked Questions

What is the time difference between Vietnam and IRST?

Vietnam (ICT, UTC+07:00) is 3 hours 30 minutes behind IRST (IRST, UTC+03:30). The gap is currently -3h 30m.

How do I convert Vietnam time to IRST time?

Add -3h 30m to Vietnam local time. For example, 9:00 AM in Vietnam is 5:30 AM in IRST.

What time is it in IRST right now?

IRST 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 Vietnam.