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.

Tehran to KST

+5h 30m

Tehran

IRSTSOURCE

Iran · UTC+03:30

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

KST

UTC+09:00

HH05

MM30

17:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Tehran

KST

12:00 AM

5:30 AM

2:00 AM

7:30 AM

4:00 AM

9:30 AM

6:00 AM

11:30 AM

8:00 AM

1:30 PM

10:00 AM

3:30 PM

12:00 PM

5:30 PM

2:00 PM

7:30 PM

4:00 PM

9:30 PM

6:00 PM

11:30 PM

8:00 PM

1:30 AM+1

10:00 PM

3:30 AM+1

Green rows indicate typical business hours (9 AM - 5 PM)

IRST and KST on the World Map

The map below highlights the IRST (Iran Standard Time) and KST (Korea Standard Time) timezone regions across the globe.

IRST Zone

→

KST Zone

Explore all world timezones interactively →

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

KST – Korea Standard Time

UTC+09:00

Korea Standard Time (KST) is the time zone for South Korea, 9 hours ahead of UTC.

Countries in KST

South KoreaNorth Korea

Major Cities in KST

SeoulBusanIncheonDaeguDaejeonPyongyang

Key Facts about KST

•South Korea does not observe daylight saving time.
•Seoul is home to Samsung, LG, and Hyundai headquarters.
•KST is the same offset as JST (UTC+09:00).

Daylight Saving:No – UTC+09:00 year-round

Learn more about KST on Wikipedia

About Tehran

Wikipedia

Tehran operates on Iran Standard Time (IRST), UTC+3:30. Iran's unique half-hour offset makes Tehran time distinctive for regional business coordination.

Population:9.4 million

Metro:16.8 million

Business Hours:8:00 AM - 4:00 PM IRST

Currency:IRR (﷼)

Stock Exchange:TSE (Tehran Stock Exchange)

Key Landmarks

Azadi TowerGolestan PalaceGrand BazaarMilad TowerTabiat Bridge

Did You Know?

Iran Standard Time (IRST) is one of few timezones with a 30-minute offset (UTC+3:30).

Learn more about IRST timezone →

Understanding the +5h 30m Gap: Tehran vs KST

Tehran runs on Iran Standard Time (IRST) at UTC+03:30. KST runs on Korea Standard Time (KST) at UTC+09:00. That puts Tehran 5 hours 30 minutes ahead of KST — a difference of +5h 30m at the current offsets.

In practice, when it is 9:00 AM in Tehran it is 2:30 PM in KST. Midnight in Tehran is 5:30 AM in KST. Neither zone observes daylight saving time, so the offset between them stays constant all year.

Tehran to KST time conversion table

Tehran (IRST)	KST (KST)	Day
12:00 AM	5:30 AM	same day
6:00 AM	11:30 AM	same day
7:00 AM	12:30 PM	same day
8:00 AM	1:30 PM	same day
9:00 AM	2:30 PM	same day
12:00 PM	5:30 PM	same day
3:00 PM	8:30 PM	same day
5:00 PM	10:30 PM	same day
6:00 PM	11:30 PM	same day
9:00 PM	2:30 AM	next day

Why people convert Tehran to KST time

Scheduling a call from Tehran to KST: a 10:00 AM start in Tehran lands at 3:30 PM in KST, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both Tehran and KST are inside the 9-to-5 working day between 9:00 AM and 11:30 AM IRST time (2:30 PM–5:00 PM KST). That is roughly 2 hours 30 minutes of usable overlap.
Keeping family and friends in sync: knowing that 8:00 PM in Tehran is 1:30 AM in KST makes it easy to avoid calling at 3 AM.

Always state the zone abbreviation, not just the hour. "3:00 PM IRST" is unambiguous; "3 PM" across a +5h 30m gap is not.
Block 9:00 AM–11:30 AM IRST as the recurring meeting window if you work primarily from Tehran and need KST colleagues present.

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.

About KST (Korea Standard Time)

Korea Standard Time (KST) is the time zone used in South Korea. It shares the same UTC offset as Japan Standard Time but is a distinct time zone. South Korea does not observe daylight saving time. Seoul, the capital, is a major global tech and business hub.

Best time to call between Tehran and KST

Both Tehran and KST sit inside the 9 AM – 5 PM working day between 9:00 AM–11:30 AM IRST, which is 2:30 PM–5:00 PM KST. That gives roughly 2 hours and 30 minutes of shared time — the safest window for a live call or meeting.

Business hours overlap

Tehran and KST overlap for about 2 hours during the working day — enough for meetings if you avoid the edges of the window.

Tehran is 5 hours 30 minutes ahead of KST (IRST UTC+03:30 → KST UTC+09:00). The shared working window is 9:00 AM–11:30 AM IRST. 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 Tehran and KST?

Tehran (IRST, UTC+03:30) is 5 hours 30 minutes ahead of KST (KST, UTC+09:00). The gap is currently +5h 30m.

How do I convert Tehran time to KST time?

Add +5h 30m to Tehran local time. For example, 9:00 AM in Tehran is 2:30 PM in KST.

What time is it in KST right now?

KST uses KST at UTC+09:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +5h 30m offset from Tehran.

What is the best time to call KST from Tehran?

Call between 9:00 AM and 11:30 AM IRST — that maps to 2:30 PM–5:00 PM KST and keeps both parties inside the working day.

Which is ahead, Tehran or KST?

Tehran is 5 hours 30 minutes ahead of KST. When it is 12:00 PM in Tehran it is 5:30 PM in KST.

Do Tehran and KST use different time zones?

Tehran (Iran) uses IRST at UTC+03:30, while KST uses KST at UTC+09:00. The IANA identifiers are Asia/Tehran and Asia/Seoul.

Does daylight saving time affect the Tehran–KST difference?

Neither zone observes daylight saving time, so the +5h 30m offset between Tehran and KST is fixed all year.

Which other cities share Tehran's time zone?

IRST also covers Tehran, Isfahan, Mashhad, Tabriz, Shiraz, Karaj.

Which countries use IRST, Tehran's zone?

IRST is used in Iran.

Is there a day difference between Tehran and KST?

Not normally. The +5h 30m gap only pushes the date over for late-evening times.

What is the time difference between Tehran and KST?

KST is +5h 30m from Tehran.

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.