KST to MST
-16hKST
KSTSOURCEMST
MSTGreen rows indicate typical business hours (9 AM - 5 PM)
KST and MST on the World Map
The map below highlights the KST (Korea Standard Time) and MST (Mountain 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).
MST – Mountain Standard Time
UTC-07:00Mountain Standard Time (MST) is the time zone for the Mountain region of North America, 7 hours behind UTC.
- •Arizona does not observe daylight saving time, staying on MST year-round.
- •The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
- •Denver, the 'Mile High City', is the largest city fully in MST.
- •MST covers 6 US states entirely and parts of several others.
Understanding the -16h Gap: KST vs MST
KST runs on Korea Standard Time (KST) at UTC+09:00. MST runs on Mountain Standard Time (MST) at UTC-07:00. That puts KST 16 hours behind MST — a difference of -16h at the current offsets.
In practice, when it is 9:00 AM in KST it is 5:00 PM in MST on the previous day. Midnight in KST is 8:00 AM in MST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
KST to MST time conversion table
| KST (KST) | MST (MST) | Day |
|---|---|---|
| 12:00 AM | 8:00 AM | previous day |
| 6:00 AM | 2:00 PM | previous day |
| 7:00 AM | 3:00 PM | previous day |
| 8:00 AM | 4:00 PM | previous day |
| 9:00 AM | 5:00 PM | previous day |
| 12:00 PM | 8:00 PM | previous day |
| 3:00 PM | 11:00 PM | previous day |
| 5:00 PM | 1:00 AM | same day |
| 6:00 PM | 2:00 AM | same day |
| 9:00 PM | 5:00 AM | same day |
Why people convert KST to MST time
- Scheduling a call from KST to MST: a 10:00 AM start in KST lands at 6:00 PM in MST the previous day, so you can confirm the slot without doing the arithmetic yourself.
- Handling a -16h gap: KST and MST 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 MST is 5:00 PM in KST.
- Keeping family and friends in sync: knowing that 8:00 PM in KST is 4:00 AM in MST makes it easy to avoid calling at 3 AM.
- Always state the zone abbreviation, not just the hour. "3:00 PM KST" is unambiguous; "3 PM" across a -16h gap is not.
- With a -16h gap there is no shared 9-to-5 window, so alternate the early start: one week KST takes the early slot, the next week MST 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 MST (Mountain Standard Time)
Mountain Standard Time (MST) covers the Rocky Mountain region of the United States and Canada. Arizona is notable for not observing daylight saving time, staying on MST year-round (except the Navajo Nation). The time zone includes major cities like Denver, Phoenix, Calgary, and Salt Lake City. During summer, most areas switch to Mountain Daylight Time (MDT, UTC-06:00).
Best time to call between KST and MST
With a -16h offset there is no overlap inside a normal 9 AM – 5 PM day. MST opens at 9:00 AM MST, which is 5:00 PM in KST, so real-time calls need an early-morning or late-evening slot on one side.
Business hours overlap
KST and MST have no shared working hours because of the -16h gap. Teams need to alternate early starts or rely on asynchronous handovers.
KST is 16 hours behind MST (KST UTC+09:00 → MST UTC-07:00). 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
MST
☀ 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 MST?
KST (KST, UTC+09:00) is 16 hours behind MST (MST, UTC-07:00). The gap is currently -16h.
How do I convert KST time to MST time?
Add -16h to KST local time. For example, 9:00 AM in KST is 5:00 PM in MST (previous day).
What time is it in MST right now?
MST uses MST at UTC-07:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -16h offset from KST.
What is the best time to call MST from KST?
There is no shared working-hours window because of the -16h gap. The closest option is 1:00 PM in KST, which is 9:00 PM in MST.
Which is behind, KST or MST?
KST is 16 hours behind MST. When it is 12:00 PM in KST it is 8:00 PM in MST.
Does daylight saving time affect the KST–MST difference?
Neither zone observes daylight saving time, so the -16h offset between KST and MST 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 MST?
Sometimes. The -16h gap is large enough that 8:00 PM or later in KST already falls on the in MST.
What is the time difference between KST and MST?
MST is -16h from KST.
What timezone is KST in?
KST operates on its local timezone.
What timezone is MST in?
MST 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 MST timezone?
Major cities in the MST timezone include Denver, Phoenix, Salt Lake City, Calgary, Edmonton, Albuquerque, El Paso, Tucson.
What is the UTC offset for MST?
Mountain Standard Time (MST) is at UTC-07:00. During daylight saving time, it shifts to MDT.
What should I know about the MST timezone?
Arizona does not observe daylight saving time, staying on MST year-round. The Navajo Nation in Arizona does observe DST, unlike the rest of the state.
When is it midnight in KST, what time is it in MST?
When it is 12:00 AM (midnight) in KST (KST), it is -16h later in MST (MST).
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