KST to UTC Time Converter
UTC is 9 hours behind KST. KST is UTC+9:00, and UTC is the zero point, UTC±00:00.
Best Time to Call Between KST and UTC
Standard 9-to-5 hours in these two zones never overlap, so someone has to take the call outside their working day. The most workable window is 4:00 PM to 10:00 PM KST, which is 7:00 AM to 1:00 PM UTC.
both at work KST only UTC only neither — hours along the strip are KST.
Common Times Converted
KST on the left, UTC on the right.
KST to UTC: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| KST | UTC | Working hours |
|---|---|---|
| 12:00 AM | 3:00 PM prev day | UTC only |
| 1:00 AM | 4:00 PM prev day | UTC only |
| 2:00 AM | 5:00 PM prev day | — |
| 3:00 AM | 6:00 PM prev day | — |
| 4:00 AM | 7:00 PM prev day | — |
| 5:00 AM | 8:00 PM prev day | — |
| 6:00 AM | 9:00 PM prev day | — |
| 7:00 AM | 10:00 PM prev day | — |
| 8:00 AM | 11:00 PM prev day | — |
| 9:00 AM | 12:00 AM | KST only |
| 10:00 AM | 1:00 AM | KST only |
| 11:00 AM | 2:00 AM | KST only |
| 12:00 PM | 3:00 AM | KST only |
| 1:00 PM | 4:00 AM | KST only |
| 2:00 PM | 5:00 AM | KST only |
| 3:00 PM | 6:00 AM | KST only |
| 4:00 PM | 7:00 AM | KST only |
| 5:00 PM | 8:00 AM | — |
| 6:00 PM | 9:00 AM | UTC only |
| 7:00 PM | 10:00 AM | UTC only |
| 8:00 PM | 11:00 AM | UTC only |
| 9:00 PM | 12:00 PM | UTC only |
| 10:00 PM | 1:00 PM | UTC only |
| 11:00 PM | 2:00 PM | UTC only |
What KST and UTC 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.
UTC — Coordinated Universal Time
The global reference standard. Aviation, computing and science run on it. Standing at UTC as written, and the region does not change its clocks, so that offset holds all year.
UTC is not a place. It is a computed standard, kept within a second of mean solar time at Greenwich by atomic clocks, and it is the reference every other zone is defined against.
What This Means in Practice
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
Frequently Asked Questions
What is the time difference between KST and UTC?
UTC is 9 hours behind KST.
What is 9:00 AM KST in UTC?
9:00 AM KST is 12:00 AM UTC.
What are the best hours to schedule a call between KST and UTC?
Standard business hours in these two zones do not overlap at all, so one side has to work outside the 9-to-5. The most workable window is 4:00 PM to 10:00 PM KST, which is 7:00 AM to 1:00 PM UTC.
Does the difference between KST and UTC change during the year?
No. Neither region changes its clocks, so this gap is fixed all year round.