MST to JST Time Converter
Japan Standard Time (JST) is currently 16 hours ahead of Mountain Standard Time (MST). MST is UTC-7 and JST is UTC+9. 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 MST, which is 9:00 AM to 5:00 PM in JST.
Comparing more than two places? The Overlap Zones tool shows working hours for several cities on one grid.
Hour by Hour: MST to JST
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?
MST and JST are fixed offsets, so the difference between them 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.
JST is UTC+9. Japan has no daylight saving, so this offset never changes.
Frequently Asked Questions
How many hours ahead is JST compared to MST?
JST is currently 16 hours ahead of MST. MST and JST are fixed offsets, so the difference between them never changes.
What time is 9:00 AM in MST in JST?
9:00 AM in MST is 1:00 AM in JST on the next day.
What is the best time for a call between MST and JST?
Both sides are inside 9:00 AM to 5:00 PM office hours between 9:00 AM and 5:00 PM in MST, which is 9:00 AM to 5:00 PM in JST.