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.

Seoul to Tehran

-5h 30m

Seoul

KSTSOURCE

South Korea · UTC+09:00

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Tehran

IRST

Iran · UTC+03:30

HH06

MM30

06:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

Seoul

Tehran

12:00 AM

6:30 PM-1

2:00 AM

8:30 PM-1

4:00 AM

10:30 PM-1

6:00 AM

12:30 AM

8:00 AM

2:30 AM

10:00 AM

4:30 AM

12:00 PM

6:30 AM

2:00 PM

8:30 AM

4:00 PM

10:30 AM

6:00 PM

12:30 PM

8:00 PM

2:30 PM

10:00 PM

4:30 PM

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

KST and IRST on the World Map

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

KST Zone

→

IRST Zone

Explore all world timezones interactively →

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

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

About Seoul

Wikipedia

Seoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.

Population:9.7 million

Metro:25.5 million

Business Hours:9:00 AM - 6:00 PM KST

Currency:KRW (₩)

Stock Exchange:KRX (Korea Exchange)

Key Landmarks

Gyeongbokgung PalaceN Seoul TowerBukchon Hanok VillageDongdaemun Design PlazaCheonggyecheon Stream

Did You Know?

Seoul has the fastest average internet speed in the world.

Learn more about KST timezone →

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 →

Seoul vs Tehran: Offsets, DST and Best Call Times

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

In practice, when it is 9:00 AM in Seoul it is 3:30 AM in Tehran. Midnight in Seoul is 6:30 PM in Tehran. Neither zone observes daylight saving time, so the offset between them stays constant all year.

Seoul to Tehran time conversion table

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

Why people convert Seoul to Tehran time

Scheduling a call from Seoul to Tehran: a 10:00 AM start in Seoul lands at 4:30 AM in Tehran, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both Seoul and Tehran are inside the 9-to-5 working day between 2:30 PM and 5:00 PM KST time (9:00 AM–11:30 AM IRST). That is roughly 2 hours 30 minutes of usable overlap.
Watching a live event or market open: Seoul viewers need 3:30 AM in Tehran to catch a 9:00 AM start there, and 5:30 AM if the event is anchored to Seoul.

Always state the zone abbreviation, not just the hour. "3:00 PM KST" is unambiguous; "3 PM" across a -5h 30m gap is not.
Block 2:30 PM–5:00 PM KST as the recurring meeting window if you work primarily from Seoul and need Tehran colleagues present.

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.

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 Seoul and Tehran

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

Business hours overlap

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

Seoul is 5 hours 30 minutes behind Tehran (KST UTC+09:00 → IRST UTC+03:30). The shared working window is 2:30 PM–5:00 PM KST. 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 Seoul and Tehran?

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

How do I convert Seoul time to Tehran time?

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

What is the best time to call Tehran from Seoul?

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

Which is behind, Seoul or Tehran?

Seoul is 5 hours 30 minutes behind Tehran. When it is 12:00 PM in Seoul it is 6:30 AM in Tehran.

Do Seoul and Tehran use different time zones?

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

Does daylight saving time affect the Seoul–Tehran difference?

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

Which other cities share Seoul's time zone?

KST also covers Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.

Which countries use KST, Seoul's zone?

KST is used in South Korea, North Korea.

Is there a day difference between Seoul and Tehran?

Not normally. The -5h 30m gap only pushes the date over the previous day.

What is the time difference between Seoul and Tehran?

Tehran is -5h 30m from Seoul.

What timezone is Seoul in?

Seoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.

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 Seoul?

Standard business hours in Seoul are 9:00 AM - 6:00 PM KST.

What are the business hours in Tehran?

Standard business hours in Tehran are 8:00 AM - 4:00 PM IRST.

What is the best time to schedule a call between Seoul and Tehran?

The best overlap for a call is when both cities are in business hours. Seoul works 9:00 AM - 6:00 PM KST and Tehran works 8:00 AM - 4:00 PM IRST (-5h 30m difference). Try scheduling during the overlapping window for maximum convenience.

What currencies are used in Seoul and Tehran?

Seoul uses KRW (₩) while Tehran uses IRR (﷼). Check current exchange rates when planning travel or business between these cities.

How do Seoul and Tehran compare in size?

Seoul has a population of approximately 9.7 million (metro: 25.5 million), while Tehran has approximately 9.4 million (metro: 16.8 million).

What are the major landmarks in Seoul and Tehran?

Seoul is known for Gyeongbokgung Palace, N Seoul Tower, Bukchon Hanok Village. Tehran is famous for Azadi Tower, Golestan Palace, Grand Bazaar.

Do Seoul and Tehran have stock exchanges?

Yes. Seoul has the KRX (Korea Exchange) and Tehran has the TSE (Tehran Stock Exchange). The -5h 30m time difference affects trading hour overlaps between these exchanges.