Does it account for Daylight Saving Time?

Yes, our converter uses the IANA timezone database, which includes all current DST rules for every timezone in the world.

UTC (Coordinated Universal Time) is the primary time standard by which the world regulates clocks. All timezones are defined as offsets from UTC.

Can I compare multiple timezones at once?

Yes, you can add multiple cities or timezones and see the equivalent times side by side.

How many timezones are there in the world?

There are 38 distinct UTC offsets in use, ranging from UTC-12 to UTC+14. This includes half-hour (UTC+5:30 India, UTC+9:30 Australia) and 45-minute offsets (UTC+5:45 Nepal, UTC+8:45 Australia).

What is the International Date Line?

The International Date Line (IDL) runs roughly along the 180° meridian in the Pacific Ocean. When you cross it westward, you gain a day; crossing eastward, you lose a day.

Why do some timezones have 30 or 45 minute offsets?

Countries chose offsets that best matched their solar noon. India uses UTC+5:30 and Nepal uses UTC+5:45 because standard hourly offsets didn't align well with their geography.

Which country has the most timezones?

France has the most (12 timezones) due to overseas territories. Russia spans 11 timezones. The US has 6 (including Hawaii and Alaska).

KST to Iran

-5h 30m

KST

KSTSOURCE

UTC+09:00

HH12

MM00

12:00 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Iran

IRST

UTC+03:30

HH06

MM30

06:30 (24-hr)

12 AM6 AM12 PM6 PM12 AM

Quick Reference

Time Conversion Table

KST

Iran

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

KST vs Iran: Offsets, DST and Best Call Times

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

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

KST to Iran time conversion table

KST (KST)	Iran (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 KST to Iran time

Scheduling a call from KST to Iran: a 10:00 AM start in KST lands at 4:30 AM in Iran, so you can confirm the slot without doing the arithmetic yourself.
Finding shared working hours: both KST and Iran 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: KST viewers need 3:30 AM in Iran to catch a 9:00 AM start there, and 5:30 AM if the event is anchored to KST.

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 KST and need Iran 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 KST and Iran

Both KST and Iran 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

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

KST is 5 hours 30 minutes behind Iran (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 KST and Iran?

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

How do I convert KST time to Iran time?

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

What time is it in Iran right now?

Iran 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 KST.