JST to MST converter

Japan Standard Time (JST) is UTC+9 with no daylight saving. It covers Tokyo, Osaka and Sapporo (Seoul shares the same clock).

Mountain Time (MST) is UTC−7 and observes daylight saving (MDT, UTC−6, roughly March–November). It covers Denver, Salt Lake City and Calgary.

Mountain Time is typically 16 hours behind Japan Standard Time, though daylight saving can shift the difference by an hour at some times of year.

Time difference between Japan Standard Time and Mountain Time

Mountain Time is typically 16 hours behind Japan Standard Time, though daylight saving can shift the difference by an hour at some times of year. Put the other way around: mountain Time (MST) is typically 16 hours behind Japan Standard Time (JST). The table above shows the difference hour by hour using today's actual offsets.

Best time to call Mountain Time from Japan Standard Time

There's no 9-to-5 overlap between Japan Standard Time and Mountain Time, so one side always has to flex. The practical slots: 8:00 AM in Japan Standard Time is 4:00 PM in Mountain Time. Daylight saving can shift these times by an hour at some points in the year.