KST to MDT
-15hKST
KSTSOURCEMDT
MDTGreen rows indicate typical business hours (9 AM - 5 PM)
KST and MDT on the World Map
The map below highlights the KST (Korea Standard Time) and MDT (Mountain Daylight 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).
MDT – Mountain Daylight Time
UTC-06:00Mountain Daylight Time (MDT) is the daylight saving offset in the Mountain Time Zone, 6 hours behind UTC.
- •MDT shares the same offset as CST (UTC-06:00).
- •Arizona does not switch to MDT, remaining on MST.
Comparing Time Zones: KST and MDT
KST runs on Korea Standard Time (KST) at UTC+09:00. MDT runs on Mountain Daylight Time (MDT) at UTC-06:00. That puts KST 15 hours behind MDT — a difference of -15h at the current offsets.
In practice, when it is 9:00 AM in KST it is 6:00 PM in MDT on the previous day. Midnight in KST is 9:00 AM in MDT. Neither zone observes daylight saving time, so the offset between them stays constant all year.
KST to MDT time conversion table
| KST (KST) | MDT (MDT) | Day |
|---|---|---|
| 12:00 AM | 9:00 AM | previous day |
| 6:00 AM | 3:00 PM | previous day |
| 7:00 AM | 4:00 PM | previous day |
| 8:00 AM | 5:00 PM | previous day |
| 9:00 AM | 6:00 PM | previous day |
| 12:00 PM | 9:00 PM | previous day |
| 3:00 PM | 12:00 AM | same day |
| 5:00 PM | 2:00 AM | same day |
| 6:00 PM | 3:00 AM | same day |
| 9:00 PM | 6:00 AM | same day |
Why people convert KST to MDT time
- Scheduling a call from KST to MDT: a 10:00 AM start in KST lands at 7:00 PM in MDT the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -15h gap: KST and MDT have no overlap inside a normal 9-to-5 day, so real-time meetings need an early-morning or late-evening slot on one side. 9:00 AM in MDT is 6:00 PM in KST.
- Watching a live event or market open: KST viewers need 6:00 PM in MDT to catch a 9:00 AM start there, and 3:00 PM 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 -15h gap is not.
- With a -15h gap there is no shared 9-to-5 window, so alternate the early start: one week KST takes the early slot, the next week MDT does.
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 MDT (Mountain Daylight Time)
Mountain Daylight Time (MDT) is observed during summer months in the Mountain Time Zone, except in Arizona which stays on MST year-round. MDT aligns with Central Standard Time (CST) at UTC-06:00.
Best time to call between KST and MDT
With a -15h offset there is no overlap inside a normal 9 AM – 5 PM day. MDT opens at 9:00 AM MDT, which is 6:00 PM in KST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
KST and MDT have no shared working hours because of the -15h gap. Teams need to alternate early starts or rely on asynchronous handovers.
KST is 15 hours behind MDT (KST UTC+09:00 → MDT UTC-06:00). There is no shared 9-to-5 window, so plan around an early or late slot. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
KST
Does not observe DST
MDT
☀ Currently in DST
Standard: UTC-07:00 · DST: UTC-06:00
Clocks fall back on Sun, Nov 1, 2026
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 MDT?
KST (KST, UTC+09:00) is 15 hours behind MDT (MDT, UTC-06:00). The gap is currently -15h.
How do I convert KST time to MDT time?
Add -15h to KST local time. For example, 9:00 AM in KST is 6:00 PM in MDT (previous day).
What time is it in MDT right now?
MDT uses MDT at UTC-06:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -15h offset from KST.
What is the best time to call MDT from KST?
There is no shared working-hours window because of the -15h gap. The closest option is 1:00 PM in KST, which is 10:00 PM in MDT.
Which is behind, KST or MDT?
KST is 15 hours behind MDT. When it is 12:00 PM in KST it is 9:00 PM in MDT.
Does daylight saving time affect the KST–MDT difference?
Neither zone observes daylight saving time, so the -15h offset between KST and MDT 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.
Is there a day difference between KST and MDT?
Sometimes. The -15h gap is large enough that 8:00 PM or later in KST already falls on the in MDT.
What is the time difference between KST and MDT?
MDT is -15h from KST.
What timezone is KST in?
KST operates on its local timezone.
What timezone is MDT in?
MDT 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 MDT timezone?
Major cities in the MDT timezone include Denver, Calgary, Edmonton, Salt Lake City, Boise.
What is the UTC offset for MDT?
Mountain Daylight Time (MDT) is at UTC-06:00. During daylight saving time, it shifts to MST.
What should I know about the MDT timezone?
MDT shares the same offset as CST (UTC-06:00). Arizona does not switch to MDT, remaining on MST.
When is it midnight in KST, what time is it in MDT?
When it is 12:00 AM (midnight) in KST (KST), it is -15h later in MDT (MDT).
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See every conversion from KST →·See every conversion from MDT →