KST to JST
+0hKST
KSTSOURCEJST
JSTGreen rows indicate typical business hours (9 AM - 5 PM)
KST and JST on the World Map
The map below highlights the KST (Korea Standard Time) and JST (Japan Standard Time) timezone regions across the globe.
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).
JST – Japan Standard Time
UTC+09:00Japan Standard Time (JST) is the time zone for Japan, 9 hours ahead of UTC.
- •Japan does not observe daylight saving time.
- •Tokyo is the most populous metropolitan area in the world.
- •The Tokyo Stock Exchange operates from 9:00 AM to 3:00 PM JST.
- •JST is 14 hours ahead of EST and 9 hours ahead of GMT.
KST to JST Time Difference – Complete Guide
KST runs on Korea Standard Time (KST) at UTC+09:00. JST runs on Japan Standard Time (JST) at UTC+09:00. That puts KST no time difference JST — a difference of +0h at the current offsets.
In practice, when it is 9:00 AM in KST it is 9:00 AM in JST. Midnight in KST is 12:00 AM in JST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
KST to JST time conversion table
| KST (KST) | JST (JST) | Day |
|---|---|---|
| 12:00 AM | 12:00 AM | same day |
| 6:00 AM | 6:00 AM | same day |
| 7:00 AM | 7:00 AM | same day |
| 8:00 AM | 8:00 AM | same day |
| 9:00 AM | 9:00 AM | same day |
| 12:00 PM | 12:00 PM | same day |
| 3:00 PM | 3:00 PM | same day |
| 5:00 PM | 5:00 PM | same day |
| 6:00 PM | 6:00 PM | same day |
| 9:00 PM | 9:00 PM | same day |
Why people convert KST to JST time
- Scheduling a call from KST to JST: a 10:00 AM start in KST lands at 10:00 AM in JST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both KST and JST are inside the 9-to-5 working day between 9:00 AM and 5:00 PM KST time (9:00 AM–5:00 PM JST). That is roughly 8 hours of usable overlap.
- Watching a live event or market open: KST viewers need 9:00 AM in JST to catch a 9:00 AM start there, and 12:00 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 +0h gap is not.
- Block 9:00 AM–5:00 PM KST as the recurring meeting window if you work primarily from KST and need JST 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 JST (Japan Standard Time)
Japan Standard Time (JST) is the standard time zone for all of Japan. Japan does not observe daylight saving time. JST is 9 hours ahead of UTC and 14 hours ahead of EST. The Tokyo Stock Exchange, the world's third largest by market capitalization, operates on JST. South Korea uses the same offset (KST) but it is a distinct time zone.
Best time to call between KST and JST
Both KST and JST sit inside the 9 AM – 5 PM working day between 9:00 AM–5:00 PM KST, which is 9:00 AM–5:00 PM JST. That gives roughly 8 hours of shared time — the safest window for a live call or meeting.
Business hours overlap
KST and JST share 8 hours of working-hours overlap (9:00 AM–5:00 PM KST), so scheduling a live meeting is straightforward.
KST is no time difference JST (KST UTC+09:00 → JST UTC+09:00). The shared working window is 9:00 AM–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:
Frequently Asked Questions
What is the time difference between KST and JST?
KST (KST, UTC+09:00) is no time difference JST (JST, UTC+09:00). The gap is currently +0h.
How do I convert KST time to JST time?
Add +0h to KST local time. For example, 9:00 AM in KST is 9:00 AM in JST.
What time is it in JST right now?
JST uses JST at UTC+09:00. Use the live converter at the top of this page — it updates in real time and already accounts for the +0h offset from KST.
What is the best time to call JST from KST?
Call between 9:00 AM and 5:00 PM KST — that maps to 9:00 AM–5:00 PM JST and keeps both parties inside the working day.
Which is ahead, KST or JST?
KST and JST are currently on the same clock.
Does daylight saving time affect the KST–JST difference?
Neither zone observes daylight saving time, so the +0h offset between KST and JST is fixed all year.
Which other cities share KST's time zone?
KST also covers Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
Which countries use KST, KST's zone?
KST is used in South Korea, North Korea.
What is the time difference between KST and JST?
JST is +0h from KST.
What timezone is KST in?
KST operates on its local timezone.
What timezone is JST in?
JST operates on its local timezone.
Which countries use KST (Korea Standard Time)?
KST is used in South Korea, North Korea.
Does KST observe daylight saving time?
No, KST does not observe daylight saving time and remains at UTC+09:00 year-round.
What are some interesting facts about KST?
South Korea does not observe daylight saving time. Seoul is home to Samsung, LG, and Hyundai headquarters.
Which cities are in the JST timezone?
Major cities in the JST timezone include Tokyo, Osaka, Yokohama, Nagoya, Sapporo, Kyoto, Kobe, Fukuoka.
What is the UTC offset for JST?
Japan Standard Time (JST) is at UTC+09:00.
What should I know about the JST timezone?
Japan does not observe daylight saving time. Tokyo is the most populous metropolitan area in the world.
When is it midnight in KST, what time is it in JST?
When it is 12:00 AM (midnight) in KST (KST), it is +0h later in JST (JST).
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