JST to MST Converter & Meeting Planner
Quick answer: 9:00 AM JST = 5:00 PM MST (fixed +09:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Japan Standard Time (JST) and Mountain Standard Time (MST)? You need to account for the standard time difference. Mountain Standard Time is normally 16 hours behind Japan Standard Time. Whether you are coordinating between teams in Tokyo and Osaka and Denver and Phoenix, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM JST = 8:00 AM MST. The full 24-hour JST to MST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM JST = 11:00 PM MST (-1 day).
| JST Time | MST Time |
|---|---|
| 12:00 AM (00:00) | 8:00 AM (08:00)-1 day |
| 1:00 AM (01:00) | 9:00 AM (09:00)-1 day |
| 2:00 AM (02:00) | 10:00 AM (10:00)-1 day |
| 3:00 AM (03:00) | 11:00 AM (11:00)-1 day |
| 4:00 AM (04:00) | 12:00 PM (12:00)-1 day |
| 5:00 AM (05:00) | 1:00 PM (13:00)-1 day |
| 6:00 AM (06:00) | 2:00 PM (14:00)-1 day |
| 7:00 AM (07:00) | 3:00 PM (15:00)-1 day |
| 8:00 AM (08:00) | 4:00 PM (16:00)-1 day |
| 9:00 AM (09:00) | 5:00 PM (17:00)-1 day |
| 10:00 AM (10:00) | 6:00 PM (18:00)-1 day |
| 11:00 AM (11:00) | 7:00 PM (19:00)-1 day |
| 12:00 PM (12:00) | 8:00 PM (20:00)-1 day |
| 1:00 PM (13:00) | 9:00 PM (21:00)-1 day |
| 2:00 PM (14:00) | 10:00 PM (22:00)-1 day |
| 3:00 PM (15:00) | 11:00 PM (23:00)-1 day |
| 4:00 PM (16:00) | 12:00 AM (00:00) |
| 5:00 PM (17:00) | 1:00 AM (01:00) |
| 6:00 PM (18:00) | 2:00 AM (02:00) |
| 7:00 PM (19:00) | 3:00 AM (03:00) |
| 8:00 PM (20:00) | 4:00 AM (04:00) |
| 9:00 PM (21:00) | 5:00 AM (05:00) |
| 10:00 PM (22:00) | 6:00 AM (06:00) |
| 11:00 PM (23:00) | 7:00 AM (07:00) |
Best time to call Denver from Tokyo
For most work calls, compare the normal business day in Tokyo (JST) with the business day in Denver (MST). JST commonly covers East Asia, while MST is mainly associated with North America.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
⚠️ There is no clean same-day business-hours overlap on 2026-07-05. A practical compromise is around 12:00 AM JST, which reaches 9:00 AM MST near the start of their workday.
- DST Safety: JST or MST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Tokyo Stock Exchange (TSE): 09:00-15:00 local time in Tokyo.
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Frequently Asked Questions
What is the time difference between JST and MST?
During standard time, Mountain Standard Time is 16 hours behind Japan Standard Time.
Does Japan observe Daylight Saving Time?
Japan has not observed Daylight Saving Time since 1951, when the practice introduced during the Allied occupation was abolished by the Japanese government. JST has remained fixed at UTC+9:00 ever since, and there is no current legislation to reintroduce DST in Japan.
Is JST the same as Korean Standard Time (KST)?
Yes, South Korea's Korean Standard Time (KST) operates at the same UTC+9:00 offset as JST, and South Korea also does not observe Daylight Saving Time. The two countries share an identical clock year-round, which simplifies scheduling for the significant trade, technology, and cultural exchange between Tokyo and Seoul.
Does Arizona observe Daylight Saving Time?
Most of Arizona — including Phoenix, Tucson, and the state government — does not observe Daylight Saving Time, remaining on MST (UTC-7) year-round under a state law in effect since 1968. The significant exception is the Navajo Nation, which spans parts of northeastern Arizona, Utah, and New Mexico and does observe DST, creating one of the most complex intrastate time zone situations in the United States.
What is the difference between MST and MDT?
MST (Mountain Standard Time) is the winter offset at UTC-7:00, observed from the first Sunday in November through the second Sunday in March. MDT (Mountain Daylight Time) is the summer offset at UTC-6:00, applied when most Mountain Time regions advance their clocks by one hour during Daylight Saving Time.