MST to JST Converter
Understanding MST and JST Time Zones
Mountain Standard Time (MST)
Mountain Standard Time is observed in undefined and uses the offset UTC-7. Major cities in this time zone include Denver, Phoenix, Salt Lake City, Albuquerque. This time zone serves a significant global region with important economic and cultural hubs.
Japan Standard Time (JST)
Japan Standard Time operates at UTC+9, covering undefined. Key cities include Tokyo, Osaka, Yokohama. The 16-hour forward offset from MST means that when professionals in Denver start their workday at 9:00 AM, it is already 1:00 AM in Tokyo.
MST is also commonly referred to as Mountain Time, MT, Arizona time, Denver time. JST is also known as Japan time, Tokyo time, Japanese time. So if you are searching for Mountain Time to Japan time, this is the same conversion as MST to JST.
Complete MST to JST Conversion Table
The table below shows every two-hour increment converted from Mountain Standard Time to Japan Standard Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.
| MST (Mountain Standard Time) | JST (Japan Standard Time) |
|---|---|
| 12:00 AM (00:00) | 4:00 PM (16:00) |
| 2:00 AM (02:00) | 6:00 PM (18:00) |
| 4:00 AM (04:00) | 8:00 PM (20:00) |
| 6:00 AM (06:00) | 10:00 PM (22:00) |
| 8:00 AM (08:00) | 12:00 AM (00:00) (next day) |
| 10:00 AM (10:00) | 2:00 AM (02:00) (next day) |
| 12:00 PM (12:00) | 4:00 AM (04:00) (next day) |
| 2:00 PM (14:00) | 6:00 AM (06:00) (next day) |
| 4:00 PM (16:00) | 8:00 AM (08:00) (next day) |
| 6:00 PM (18:00) | 10:00 AM (10:00) (next day) |
| 8:00 PM (20:00) | 12:00 PM (12:00) (next day) |
| 10:00 PM (22:00) | 2:00 PM (14:00) (next day) |
Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.
Scheduling Between MST and JST
When coordinating deliverables across MST and JST, set deadlines in the earlier time zone to avoid end-of-day confusion. A "5 PM deadline" should specify which zone to prevent missed deliveries due to the 16-hour offset.
The large 16-hour gap between MST and JST means that finding overlapping working hours requires compromise from at least one side. Consider adopting asynchronous workflows — recorded video updates, shared documents, and time-zone-aware project management tools — to supplement the limited real-time overlap.
Travel Between Denver and Tokyo
Flight times between Denver and Tokyo often appear misleading because of the time zone shift. A departure at 10:00 AM MST arriving at 2:00 PM JST may look long, but remember to factor in the 16-hour offset.
Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 16-hour shift between MST and JST, plan for roughly one week of gradual adjustment for optimal performance.
Daylight Saving Time Considerations
Countries near the equator — including Singapore, most of Africa, and parts of South America — do not observe DST, making their offsets constant year-round. This simplifies scheduling compared to US or European zones.
For the MST to JST conversion specifically: MST (UTC-7) observes DST, while JST (UTC+9) does not observe DST. This means the offset between them changes by one hour seasonally — the usual 16-hour gap becomes 15 or 17 hours during DST transitions.
Related Time Zone Conversions
References & Resources
Frequently Asked Questions
MST (Mountain Standard Time) is 16 hours behind JST (Japan Standard Time). MST is UTC-7 and JST is UTC+9.
When it is 12:00 PM (noon) in MST, it is 4:00 AM (next day) in JST.
The best overlap for business hours is approximately 1:00 AM to 9:00 AM JST, which corresponds to 9:00 AM to 5:00 PM in MST. Given the large gap, consider alternating between early and late meeting times.
Countries near the equator — including Singapore, most of Africa, and parts of South America — do not observe DST, making their offsets constant year-round. This simplifies scheduling compared to US or European zones.