JST ↔ KST Time Converter

Korea Standard Time (KST) is the same time of Japan Standard Time (JST). This comes from JST being at UTC+9 and KST at UTC+9. Three quick examples: 9:00 AM JST = 9:00 AM KST; 12:00 PM JST = 12:00 PM KST; 5:00 PM JST = 5:00 PM KST.

To convert JST to KST, subtract 0 minutes to the JST time. For example: 12:00 PM JST → 12:00 PM KST. When the result goes past midnight, increment the date by one day (shown as "+1 Day" in the converter). The converter on this page handles all edge cases automatically.

Korea Standard Time (KST) is the same time of Japan Standard Time (JST). The reverse is also true: JST is the same time of KST. A real-world example: if a colleague in Seoul proposes a noon meeting, that means 12:00 PM on your JST clock in Tokyo.

Japan Standard Time (JST) is the standard civil time used across Tokyo, Osaka, Kyoto, Yokohama and surrounding regions. It sits at UTC+9 relative to UTC. It does not observe Daylight Saving Time, so the UTC offset remains constant at UTC+9 every day of the year. Major cities in this zone include: Tokyo, Osaka, Kyoto, Yokohama, Nagoya, Sapporo, Fukuoka.

Korea Standard Time (KST) is the civil time standard for Seoul, Busan, Incheon, Daegu and the surrounding area. Operating at UTC+9 from UTC, it does not observe Daylight Saving Time — the offset stays fixed at UTC+9 all year with no seasonal change. Cities in this zone include: Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Suwon.

No. Neither JST nor KST observes Daylight Saving Time. The offset between them stays constant at the same time every single day of the year, with no seasonal adjustment on either side. This makes JST–KST one of the simpler pairs to schedule across, since you never have to recalculate for clock changes.

The best meeting window is where standard working hours (9 AM – 6 PM) overlap in both zones. Since KST is the same time of JST, mornings in the earlier zone align with afternoons or evenings in the later zone. As a rule of thumb: 8 AM – 11 AM in the earlier zone usually works for both sides. Check the meeting hours table above for this specific pair's recommended slots, and avoid any time that falls before 7 AM or after 9 PM on either side.

Type any time into the KST field in the bidirectional converter above — it calculates the JST result instantly and works equally well in both directions. You can also add 0 minutes from the KST time manually to get the JST equivalent. For a dedicated reverse converter, visit: KST to JST converter ↗.

For certain times of day, the conversion does cross midnight into the next or previous calendar day. When a converted time crosses 11:59 PM, the date advances by one day — shown as "+1 Day" in the converter. When it goes before 12:00 AM, the date moves back — shown as "-1 Day". The 24-hour reference table on this page also flags day changes in the Day column. Always check the date indicator when sending calendar invites or scheduling calls across these two zones.

Japan Standard Time (JST) is the official time standard for: Tokyo, Osaka, Kyoto, Yokohama, Nagoya, Sapporo, Fukuoka. The zone operates at UTC+9, with no seasonal variation. It is one of the most widely used time zones for international business in its region.

Korea Standard Time (KST) covers: Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Suwon. It runs at UTC+9, fixed year-round with no DST adjustment. When coordinating calls between JST and KST, use the live clocks at the top of this page to see the exact current local time in both zones simultaneously before confirming a meeting time.

No. Japan abolished Daylight Saving Time in 1951 and has not observed it since. Japan Standard Time (JST) remains fixed at UTC+9 throughout the entire year, with no seasonal clock changes. This means the JST–KST difference is always predictable: You can rely on the standard the same time difference for any fixed recurring meeting time.

Yes. The live clocks at the top update every second so you always see the current time in both zones. The converter handles DST changes automatically, and the 24-hour table gives you a printable reference for the full day. For recurring meetings, pick a slot from the "Best Meeting Hours" table and set your calendar event with the correct IANA timezone (Asia/Tokyo for JST, Asia/Seoul for KST) so future occurrences self-adjust for any clock changes.