JST to MST Time Converter
Mountain Standard Time (MST) is currently 16 hours behind Japan Standard Time (JST). JST is UTC+9 and MST is UTC-7. The table below converts every hour of the day between the two, and the call planner shows where working hours line up.
Best Time for a Call
Both sides are inside 9:00 AM to 5:00 PM office hours between 9:00 AM and 5:00 PM in JST, which is 9:00 AM to 5:00 PM in MST.
Comparing more than two places? The Overlap Zones tool shows working hours for several cities on one grid.
Hour by Hour: JST to MST
Rows marked office hours fall between 9:00 AM and 5:00 PM in both places. For a specific date, use the interactive converter.
Does the Difference Change During the Year?
JST and MST are fixed offsets, so the difference between them never changes.
JST is UTC+9. Japan has no daylight saving, so this offset never changes.
MST is UTC-7. Most of the Mountain region switches to MDT (UTC-6) in summer, but Arizona stays on MST year round.
Frequently Asked Questions
How many hours behind is MST compared to JST?
MST is currently 16 hours behind JST. JST and MST are fixed offsets, so the difference between them never changes.
What time is 9:00 AM in JST in MST?
9:00 AM in JST is 5:00 PM in MST on the previous day.
What is the best time for a call between JST and MST?
Both sides are inside 9:00 AM to 5:00 PM office hours between 9:00 AM and 5:00 PM in JST, which is 9:00 AM to 5:00 PM in MST.