No overlap — one side will join outside working hours
KST (Seoul)
MST (Denver)
00:00
09:00-1dWorking
01:00
10:00-1dWorking
02:00
11:00-1dWorking
03:00
12:00-1dWorking
04:00
13:00-1dWorking
05:00
14:00-1dWorking
06:00
15:00-1dWorking
07:00
16:00-1dWorking
08:00
17:00-1d
09:00Working
18:00-1doff
10:00Working
19:00-1doff
11:00Working
20:00-1doff
12:00Working
21:00-1doff
13:00Working
22:00-1doff
14:00Working
23:00-1doff
15:00Working
00:00off
16:00Working
01:00off
17:00
02:00
18:00
03:00
19:00
04:00
20:00
05:00
21:00
06:00
22:00
07:00
23:00
08:00
Working hours: 09:00–17:00 local. Green = both working.Purple = one side only.
Frequently Asked Questions
What is the difference between kst and mst?
Korea Standard Time (kst) is UTC+9 and Mountain Standard Time (mst) is UTC-6. The difference between them is 15 hours.
Where is kst used?
Korea Standard Time (kst) is used in South Korea and surrounding regions. The IANA timezone identifier is Asia/Seoul.
Where is mst used?
Mountain Standard Time (mst) is used in USA and surrounding regions. The IANA timezone identifier is America/Denver.
How do I convert kst to mst?
Use the interactive converter above. Drag the time slider to any kst time and the mst equivalent updates instantly. You can also type a time like "3pm" or "15:00" in the input bar.
KST (Seoul) is 15 hours ahead of MST (Denver). Midday in KST (Seoul) lines up with 21:00 in MST (Denver).
KST (Seoul) observes Asia/Seoul and MST (Denver) observes America/Denver — a 15 hours gap between them.
Business hours comparison
When KST (Seoul) is in standard working hours, MST (Denver) is not — and vice versa. There is no mutual business window between these two locations.
Optimal meeting slots
No business hours overlap exists between KST (Seoul) and MST (Denver). Showing the most balanced options with minimal inconvenience for both locations.
07:00 Seoul / 16:00 Denver⚡ One side off-hours
⚠️ 2h before working hours in Seoul
09:00 Seoul / 18:00 Denver⚡ One side off-hours
⚠️ 2h after working hours in Denver
06:00 Seoul / 15:00 Denver⚡ One side off-hours
⚠️ 3h before working hours in Seoul
Assumes a standard 9 AM–5 PM workday in each location's local timezone.
Upcoming public holidays
⚡ Watch out — upcoming holidays on both sides. Verify availability in advance.
KST (Seoul)7 holidays
Aug 15Liberation Day
Sep 24Chuseok
Sep 25Chuseok
Sep 26Chuseok
Oct 3National Foundation Day
MST (Denver)8 holidays
Jun 19Juneteenth National Independence DaySOON
Jul 3Independence Day
Sep 7Labour Day
Oct 12Columbus Day
Oct 12Indigenous Peoples' Day
How to work with KST (Seoul) and MST (Denver) time zones
Teams in KST (Seoul) (South Korea) and MST (Denver) (USA) deal with a 15-hour gap that pushes their working days apart. Real-time meetings always require someone to stretch outside the standard 9–5.
💡 How to schedule across these time zones
⚡
07:00–08:00 in KST (Seoul) corresponds to 16:00–17:00 in MST (Denver) (2h before working hours in Seoul).
⚡
09:00–10:00 in KST (Seoul) corresponds to 18:00–19:00 in MST (Denver) (2h after working hours in Denver).
⚡
06:00–07:00 in KST (Seoul) corresponds to 15:00–16:00 in MST (Denver) (3h before working hours in Seoul).
Since there is no natural overlap, the options above represent the most balanced compromise, minimizing out-of-hours inconvenience for both sides.
Recurring meetings are particularly vulnerable to DST shifts. The ClockinSync Chrome Extension alerts you before the offset changes.
Drag the slider at the top to convert any KST (Seoul) time instantly. You can also type natural language like "3pm", "15:00", or a location name to get an immediate answer.
