KST to IST Time Converter
IST is 3 hours and 30 minutes behind KST. KST is UTC+9:00, and IST is UTC+5:30.
Best Time to Call Between KST and IST
Both zones are inside normal business hours between 1:00 PM and 5:00 PM KST — that's 9:30 AM to 1:30 PM IST. That's a 4-hour window.
both at work KST only IST only neither — hours along the strip are KST.
Common Times Converted
KST on the left, IST on the right.
KST to IST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| KST | IST | Working hours |
|---|---|---|
| 12:00 AM | 8:30 PM prev day | — |
| 1:00 AM | 9:30 PM prev day | — |
| 2:00 AM | 10:30 PM prev day | — |
| 3:00 AM | 11:30 PM prev day | — |
| 4:00 AM | 12:30 AM | — |
| 5:00 AM | 1:30 AM | — |
| 6:00 AM | 2:30 AM | — |
| 7:00 AM | 3:30 AM | — |
| 8:00 AM | 4:30 AM | — |
| 9:00 AM | 5:30 AM | KST only |
| 10:00 AM | 6:30 AM | KST only |
| 11:00 AM | 7:30 AM | KST only |
| 12:00 PM | 8:30 AM | KST only |
| 1:00 PM | 9:30 AM | Both zones |
| 2:00 PM | 10:30 AM | Both zones |
| 3:00 PM | 11:30 AM | Both zones |
| 4:00 PM | 12:30 PM | Both zones |
| 5:00 PM | 1:30 PM | IST only |
| 6:00 PM | 2:30 PM | IST only |
| 7:00 PM | 3:30 PM | IST only |
| 8:00 PM | 4:30 PM | IST only |
| 9:00 PM | 5:30 PM | — |
| 10:00 PM | 6:30 PM | — |
| 11:00 PM | 7:30 PM | — |
What KST and IST Actually Are
KST — Korea Standard Time
Seoul, Busan, Incheon. Standing at UTC+9:00 as written, and the region does not change its clocks, so that offset holds all year.
South Korea has used daylight saving only twice, most recently for the 1988 Seoul Olympics, and has kept a fixed offset since.
IST — India Standard Time
Mumbai, Delhi, Bengaluru, Chennai, Kolkata, Hyderabad — and Colombo. Standing at UTC+5:30 as written, and the region does not change its clocks, so that offset holds all year. IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.
India runs a single time zone across a country wide enough for two, which is why sunrise in the north-east can come nearly two hours before Mumbai's. Proposals for a second zone resurface regularly and have never been adopted.
What This Means in Practice
Expect times on the half hour
IST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.
A gap you can rely on
Neither region changes its clocks, so this difference holds every day of the year. A recurring meeting booked once stays correct — worth knowing, because most cross-border pairs cannot say that.
Major Cities in Each Zone
Cities on KST
Cities on IST
Frequently Asked Questions
What is the time difference between KST and IST?
IST is 3 hours and 30 minutes behind KST.
What is 9:00 AM KST in IST?
9:00 AM KST is 5:30 AM IST.
What are the best hours to schedule a call between KST and IST?
Between 1:00 PM and 5:00 PM KST, which is 9:30 AM to 1:30 PM IST. Both sides are inside normal business hours through that window.
Does the difference between KST and IST change during the year?
No. Neither region changes its clocks, so this gap is fixed all year round.
Does IST always mean India Standard Time?
IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.