IST to Seoul
+3h 30mIST
ISTSOURCESeoul
KSTGreen rows indicate typical business hours (9 AM - 5 PM)
IST and KST on the World Map
The map below highlights the IST (India Standard Time) and KST (Korea Standard Time) timezone regions across the globe.
IST – India Standard Time
UTC+05:30India Standard Time (IST) is the time zone for India and Sri Lanka, 5 hours and 30 minutes ahead of UTC.
- •India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT.
- •India uses a single time zone despite spanning 30° of longitude.
- •IST is one of only a handful of time zones with a 30-minute offset.
- •IST is the most populous single time zone in the world with over 1.4 billion people.
- •The Bombay Stock Exchange (BSE) and National Stock Exchange (NSE) operate on IST.
KST – Korea Standard Time
UTC+09:00Korea Standard Time (KST) is the time zone for South Korea, 9 hours ahead of UTC.
- •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).
About Seoul
WikipediaSeoul operates on Korea Standard Time (KST), UTC+9, same as Japan. As a global tech and entertainment hub, Seoul coordinates with East Asian markets.
Seoul has the fastest average internet speed in the world.
Understanding the +3h 30m Gap: IST vs Seoul
IST runs on India Standard Time (IST) at UTC+05:30. Seoul runs on Korean Standard Time (KST) at UTC+09:00. That puts IST 3 hours 30 minutes ahead of Seoul — a difference of +3h 30m at the current offsets.
In practice, when it is 9:00 AM in IST it is 12:30 PM in Seoul. Midnight in IST is 3:30 AM in Seoul. Neither zone observes daylight saving time, so the offset between them stays constant all year.
IST to Seoul time conversion table
| IST (IST) | Seoul (KST) | Day |
|---|---|---|
| 12:00 AM | 3:30 AM | same day |
| 6:00 AM | 9:30 AM | same day |
| 7:00 AM | 10:30 AM | same day |
| 8:00 AM | 11:30 AM | same day |
| 9:00 AM | 12:30 PM | same day |
| 12:00 PM | 3:30 PM | same day |
| 3:00 PM | 6:30 PM | same day |
| 5:00 PM | 8:30 PM | same day |
| 6:00 PM | 9:30 PM | same day |
| 9:00 PM | 12:30 AM | next day |
Why people convert IST to Seoul time
- Scheduling a call from IST to Seoul: a 10:00 AM start in IST lands at 1:30 PM in Seoul, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both IST and Seoul are inside the 9-to-5 working day between 9:00 AM and 1:30 PM IST time (12:30 PM–5:00 PM KST). That is roughly 4 hours 30 minutes of usable overlap.
- Coordinating a IST-based team with Seoul contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM IST" is unambiguous; "3 PM" across a +3h 30m gap is not.
- Block 9:00 AM–1:30 PM IST as the recurring meeting window if you work primarily from IST and need Seoul colleagues present.
About IST (India Standard Time)
India Standard Time (IST) is the time observed throughout India and Sri Lanka. It is based on the 82.5°E meridian, passing through Mirzapur in Uttar Pradesh. India uses a single time zone despite spanning roughly 30° of longitude, which has been debated. IST does not observe daylight saving time. India is the world's most populous country, making IST one of the most-used time zones globally. The IT outsourcing industry and call centers operate primarily on IST, making the EST-to-IST conversion one of the most searched timezone conversions.
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 IST and Seoul
Both IST and Seoul sit inside the 9 AM – 5 PM working day between 9:00 AM–1:30 PM IST, which is 12:30 PM–5:00 PM KST. That gives roughly 4 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
IST and Seoul overlap for about 4 hours during the working day — enough for meetings if you avoid the edges of the window.
IST is 3 hours 30 minutes ahead of Seoul (IST UTC+05:30 → KST UTC+09:00). The shared working window is 9:00 AM–1:30 PM IST. 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 IST and Seoul?
IST (IST, UTC+05:30) is 3 hours 30 minutes ahead of Seoul (KST, UTC+09:00). The gap is currently +3h 30m.
How do I convert IST time to Seoul time?
Add +3h 30m to IST local time. For example, 9:00 AM in IST is 12:30 PM in Seoul.
What time is it in Seoul right now?
Seoul 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 +3h 30m offset from IST.
What is the best time to call Seoul from IST?
Call between 9:00 AM and 1:30 PM IST — that maps to 12:30 PM–5:00 PM KST and keeps both parties inside the working day.
Which is ahead, IST or Seoul?
IST is 3 hours 30 minutes ahead of Seoul. When it is 12:00 PM in IST it is 3:30 PM in Seoul.
Do IST and Seoul use different time zones?
IST uses IST at UTC+05:30, while Seoul (South Korea) uses KST at UTC+09:00. The IANA identifiers are Asia/Kolkata and Asia/Seoul.
Does daylight saving time affect the IST–Seoul difference?
Neither zone observes daylight saving time, so the +3h 30m offset between IST and Seoul is fixed all year.
Which other cities share IST's time zone?
IST also covers Mumbai, Delhi, Bangalore, Kolkata, Chennai, Hyderabad, Pune, Ahmedabad and 4 more.
Which countries use IST, IST's zone?
IST is used in India, Sri Lanka.
Is there a day difference between IST and Seoul?
Not normally. The +3h 30m gap only pushes the date over for late-evening times.
What is the time difference between IST and Seoul?
Seoul is +3h 30m from IST.
What timezone is IST in?
IST operates on its local timezone.
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 are the business hours in Seoul?
Standard business hours in Seoul are 9:00 AM - 6:00 PM KST.
Which countries use IST (India Standard Time)?
IST is used in India, Sri Lanka.
Does IST observe daylight saving time?
No, IST does not observe daylight saving time and remains at UTC+05:30 year-round.
What are some interesting facts about IST?
India is 10 hours 30 minutes ahead of EST and 5 hours 30 minutes ahead of GMT. India uses a single time zone despite spanning 30° of longitude.
Which cities are in the KST timezone?
Major cities in the KST timezone include Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
What is the UTC offset for KST?
Korea Standard Time (KST) is at UTC+09:00.
What should I know about the KST timezone?
South Korea does not observe daylight saving time. Seoul is home to Samsung, LG, and Hyundai headquarters.
When is it midnight in IST, what time is it in Seoul?
When it is 12:00 AM (midnight) in IST (IST), it is +3h 30m later in Seoul (KST).
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