JST to MDT Converter & Meeting Planner
Quick answer: 9:00 AM JST = 6:00 PM MDT (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 Daylight Time (MDT)? You need to account for the standard time difference. Mountain Daylight Time is normally 15 hours behind Japan Standard Time. Whether you are coordinating between teams in Tokyo and Osaka and Denver and Salt Lake City, 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 = 9:00 AM MDT. The full 24-hour JST to MDT table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM JST = 12:00 AM MDT.
| JST Time | MDT Time |
|---|---|
| 12:00 AM (00:00) | 9:00 AM (09:00)-1 day |
| 1:00 AM (01:00) | 10:00 AM (10:00)-1 day |
| 2:00 AM (02:00) | 11:00 AM (11:00)-1 day |
| 3:00 AM (03:00) | 12:00 PM (12:00)-1 day |
| 4:00 AM (04:00) | 1:00 PM (13:00)-1 day |
| 5:00 AM (05:00) | 2:00 PM (14:00)-1 day |
| 6:00 AM (06:00) | 3:00 PM (15:00)-1 day |
| 7:00 AM (07:00) | 4:00 PM (16:00)-1 day |
| 8:00 AM (08:00) | 5:00 PM (17:00)-1 day |
| 9:00 AM (09:00) | 6:00 PM (18:00)-1 day |
| 10:00 AM (10:00) | 7:00 PM (19:00)-1 day |
| 11:00 AM (11:00) | 8:00 PM (20:00)-1 day |
| 12:00 PM (12:00) | 9:00 PM (21:00)-1 day |
| 1:00 PM (13:00) | 10:00 PM (22:00)-1 day |
| 2:00 PM (14:00) | 11:00 PM (23:00)-1 day |
| 3:00 PM (15:00) | 12:00 AM (00:00) |
| 4:00 PM (16:00) | 1:00 AM (01:00) |
| 5:00 PM (17:00) | 2:00 AM (02:00) |
| 6:00 PM (18:00) | 3:00 AM (03:00) |
| 7:00 PM (19:00) | 4:00 AM (04:00) |
| 8:00 PM (20:00) | 5:00 AM (05:00) |
| 9:00 PM (21:00) | 6:00 AM (06:00) |
| 10:00 PM (22:00) | 7:00 AM (07:00) |
| 11:00 PM (23:00) | 8:00 AM (08:00) |
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 (MDT). JST commonly covers East Asia, while MDT 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 MDT near the start of their workday.
- DST Safety: JST or MDT 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 MDT?
During standard time, Mountain Daylight Time is 15 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.
When does MDT start and end?
MDT begins on the second Sunday in March at 02:00 local MST time, when clocks spring forward one hour from MST (UTC-7) to MDT (UTC-6). It ends on the first Sunday in November at 02:00 local MDT time, when clocks fall back to MST. In 2026, MDT runs from March 8 through November 1, covering the majority of the calendar year.
Is Arizona on MDT?
Most of Arizona — including Phoenix and Tucson — does not observe Daylight Saving Time and remains on MST (UTC-7) year-round under a state law in effect since 1968, meaning Arizona does not advance to MDT each March. The significant exception is the Navajo Nation, a sovereign territory spanning parts of northeastern Arizona, southeastern Utah, and northwestern New Mexico, which does observe DST and shifts to MDT on the standard federal schedule.