The short answer
11am in Japan Standard Time is 8pm in Mountain Standard Time on the previous day.
Japan Standard Time is 15 hours ahead of Mountain Standard Time. That's already evening in Mountain Standard Time, after the typical working day ends.
Japan Standard Time☀
11am
Mountain Standard Time☀
8pm
previous day
Right now
9:37pmJST · UTC+09:00 · Mon, Jun 22
6:37amMDT · UTC-06:00 · Mon, Jun 22
Read across to convert
Japan Standard Time
JST · UTC+09:00
Mountain Standard Time
MDT · UTC-06:00
Pinned11amJapan Standard Time=8pmMountain Standard 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
PINNED
11am
WORK8pmSun ·−1d
12pm
WORK9pmSun ·−1d
1pm
WORK10pmSun ·−1d
2pm
WORK11pmSun ·−1d
3pm
WORK12amMon
4pm
WORK1am
5pm
2am
6pm
3am
7pm
4am
8pm
5am
NOW
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.
Japan Standard Time
7am–10am
Mountain Standard Time
4pm–7pm
previous day
Popular conversions
Quick reference.
9amJapan Standard Time=6pmMountain Standard Time · prev day
12pmJapan Standard Time=9pmMountain Standard Time · prev day
3pmJapan Standard Time=12amMountain Standard Time
5pmJapan Standard Time=2amMountain Standard Time
9pmJapan Standard Time=6amMountain Standard Time
In context
What each side covers.
Japan Standard Time
9:37pmJST · UTC+09:00
Mountain Standard Time
6:37amMDT · UTC-06:00
Cities on this clock
Related converters
Other popular pairs.
Pacific Time
5:37am
India Standard Time
6:07pm
Pacific Time to India12 hours 30 minutes behind
Eastern Standard Time
8:37am
Central European Time
2:37pm
Eastern Time to Central Europe6 hours behind
India Standard Time
6:07pm
Eastern Standard Time
8:37am
India to Eastern Time9 hours 30 minutes ahead
Greenwich Mean Time
1:37pm
India Standard Time
6:07pm
London to India4 hours 30 minutes behind
Pacific Standard Time
5:37am
Eastern Standard Time
8:37am
Pacific to Eastern Time3 hours behind
Central European Time
2:37pm
India Standard Time
6:07pm
Central Europe to India3 hours 30 minutes behind
Frequently asked
Quick answers about converting between Japan Standard Time and Mountain Standard Time. Can't find what you need? Email [email protected].
- What is the time difference between Japan Standard Time and Mountain Standard Time?
- Japan Standard Time is 15 hours ahead of Mountain Standard 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 11am in Japan Standard Time, what time is it in Mountain Standard Time?
- 11am in Japan Standard Time is 8pm in Mountain Standard Time on the previous day. That's already evening in Mountain Standard Time, after the typical working day ends. Use the hour-by-hour table above to read any other time across.
- What's the best time for a call between Japan Standard Time and Mountain Standard Time?
- There's no comfortable 9-to-5 overlap between Japan Standard Time and Mountain Standard 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 — JST 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.