The short answer
12pm in Korea Standard Time is 9pm in Mountain Time on the previous day.
Korea Standard Time is 15 hours ahead of Mountain Time. It lands deep outside working hours in Mountain Time — see the best time to meet below for a friendlier slot.
Korea Standard Time☀
12pm
Mountain Time☾
9pm
previous day
Right now
4:39pmKST · UTC+09:00 · Mon, Jun 22
1:39amMDT · UTC-06:00 · Mon, Jun 22
Read across to convert
Korea Standard Time
KST · UTC+09:00
Mountain Time
MDT · UTC-06:00
Pinned12pmKorea Standard Time=9pmMountain Time · Sun (previous day)
12amMon
9amSun ·−1d
WORK1am
10amSun ·−1d
WORK2am
11amSun ·−1d
WORK3am
12pmSun ·−1d
WORK4am
1pmSun ·−1d
WORK5am
2pmSun ·−1d
WORK6am
3pmSun ·−1d
WORK7am
4pmSun ·−1d
WORK8am
5pmSun ·−1d
9am
WORK6pmSun ·−1d
10am
WORK7pmSun ·−1d
11am
WORK8pmSun ·−1d
PINNED
12pm
WORK9pmSun ·−1d
1pm
WORK10pmSun ·−1d
2pm
WORK11pmSun ·−1d
3pm
WORK12amMon
NOW
4pm
WORK1am
5pm
2am
6pm
3am
7pm
4am
8pm
5am
9pm
6am
10pm
7am
11pm
8am
daylightnightworking hoursoverlap
Best time to meet=
Closest workable window
Just outside the working window — early on one side, late on the other.
Korea Standard Time
7am–10am
Mountain Time
4pm–7pm
previous day
Popular conversions
Quick reference.
9amKorea Standard Time=6pmMountain Time · prev day
12pmKorea Standard Time=9pmMountain Time · prev day
3pmKorea Standard Time=12amMountain Time
5pmKorea Standard Time=2amMountain Time
9pmKorea Standard Time=6amMountain Time
In context
What each side covers.
Korea Standard Time
4:39pmKST · UTC+09:00
Mountain Time
1:39amMDT · UTC-06:00
Cities on this clock
Related converters
Other popular pairs.
Pacific Time
12:39am
India Standard Time
1:09pm
Pacific Time to India12 hours 30 minutes behind
Eastern Standard Time
3:39am
Central European Time
9:39am
Eastern Time to Central Europe6 hours behind
India Standard Time
1:09pm
Eastern Standard Time
3:39am
India to Eastern Time9 hours 30 minutes ahead
Greenwich Mean Time
8:39am
India Standard Time
1:09pm
London to India4 hours 30 minutes behind
Pacific Standard Time
12:39am
Eastern Standard Time
3:39am
Pacific to Eastern Time3 hours behind
Central European Time
9:39am
India Standard Time
1:09pm
Central Europe to India3 hours 30 minutes behind
Frequently asked
Quick answers about converting between Korea Standard Time and Mountain Time. Can't find what you need? Email [email protected].
- What is the time difference between Korea Standard Time and Mountain Time?
- Korea Standard Time is 15 hours ahead of Mountain Time right now. We always show the live, daylight-saving-correct difference, so this figure already accounts for whichever side is observing summer time today.
- When it's 12pm in Korea Standard Time, what time is it in Mountain Time?
- 12pm in Korea Standard Time is 9pm in Mountain Time on the previous day. It lands deep outside working hours in Mountain Time — see the best time to meet below for a friendlier slot. Use the hour-by-hour table above to read any other time across.
- What's the best time for a call between Korea Standard Time and Mountain Time?
- There's no comfortable 9-to-5 overlap between Korea Standard Time and Mountain Time — they sit on opposite sides of the planet's working day. Plan for an early or late call on one side, or hand work off asynchronously.
- Does this account for daylight saving time?
- Yes. We track every clock change in both places, so the abbreviations you see — KST and MDT — are the ones actually in effect right now, not a fixed all-year value. When either side changes its clocks, this page updates automatically.
- Why is the date sometimes different on each side?
- When two places are far enough apart, the same moment can fall on different calendar days. That is why some conversions are marked "previous day" or "next day" — it is the same instant in time, read off two clocks that crossed midnight at different points.