JST to MST Converter
See the current time in JST (Tokyo) and MST (Denver) side by side, the exact time difference right now, and convert any time between the two zones.
JST to MST Converter
Uses your browser's built-in, DST-aware time-zone data.
About converting JST to MST
Japan Standard Time (Tokyo) and Mountain Time (Denver) are in different time zones, so a meeting, call or stream that's convenient in one may be early or late in the other. The clocks above update live and account for daylight saving automatically, so the time difference you see is the real one for today — not a fixed number that goes stale twice a year.
To plan across the two, type a time into the JST box (or tap a quick preset) and read the MST equivalent, including a "next day" or "previous day" note when the conversion crosses midnight. For any other pair of zones or cities, use the full timezone converter.
JST vs MST: the time difference through the year
The gap between JST and MST changes during the year because only one of them uses daylight saving.
| Period | Difference |
|---|---|
| Oct 23, 2026 – Oct 31, 2026 | MST 15 h behind JST |
| Nov 1, 2026 – Mar 13, 2027 | MST 16 h behind JST |
| Mar 14, 2027 – Oct 23, 2027 | MST 15 h behind JST |
Daylight-saving changes in the next year
| Zone | Date | Offset | Change |
|---|---|---|---|
| MST | Nov 1, 2026 | UTC−6 → UTC−7 | Clocks go back 1 hour |
| MST | Mar 14, 2027 | UTC−7 → UTC−6 | Clocks go forward 1 hour |
| MST | Nov 7, 2027 | UTC−6 → UTC−7 | Clocks go back 1 hour |
JST to MST conversion table
| JST | MST (when 15 h behind) | MST (when 16 h behind) |
|---|---|---|
| 12:00 AM | 9:00 AM (previous day) | 8:00 AM (previous day) |
| 1:00 AM | 10:00 AM (previous day) | 9:00 AM (previous day) |
| 2:00 AM | 11:00 AM (previous day) | 10:00 AM (previous day) |
| 3:00 AM | 12:00 PM (previous day) | 11:00 AM (previous day) |
| 4:00 AM | 1:00 PM (previous day) | 12:00 PM (previous day) |
| 5:00 AM | 2:00 PM (previous day) | 1:00 PM (previous day) |
| 6:00 AM | 3:00 PM (previous day) | 2:00 PM (previous day) |
| 7:00 AM | 4:00 PM (previous day) | 3:00 PM (previous day) |
| 8:00 AM | 5:00 PM (previous day) | 4:00 PM (previous day) |
| 9:00 AM | 6:00 PM (previous day) | 5:00 PM (previous day) |
| 10:00 AM | 7:00 PM (previous day) | 6:00 PM (previous day) |
| 11:00 AM | 8:00 PM (previous day) | 7:00 PM (previous day) |
| 12:00 PM | 9:00 PM (previous day) | 8:00 PM (previous day) |
| 1:00 PM | 10:00 PM (previous day) | 9:00 PM (previous day) |
| 2:00 PM | 11:00 PM (previous day) | 10:00 PM (previous day) |
| 3:00 PM | 12:00 AM | 11:00 PM (previous day) |
| 4:00 PM | 1:00 AM | 12:00 AM |
| 5:00 PM | 2:00 AM | 1:00 AM |
| 6:00 PM | 3:00 AM | 2:00 AM |
| 7:00 PM | 4:00 AM | 3:00 AM |
| 8:00 PM | 5:00 AM | 4:00 AM |
| 9:00 PM | 6:00 AM | 5:00 AM |
| 10:00 PM | 7:00 AM | 6:00 AM |
| 11:00 PM | 8:00 AM | 7:00 AM |
Best time to meet
- 9 AM–5 PM overlap when MST is 15 h behindnone — closest fit 8:00 AM–11:00 AM JST = 5:00 PM–8:00 PM MST (8 AM–8 PM in both)
- 9 AM–5 PM overlap when MST is 16 h behindnone — closest fit 8:00 AM–12:00 PM JST = 4:00 PM–8:00 PM MST (8 AM–8 PM in both)
The two zones
Japan Standard Time is UTC+9 all year. Japan has not used daylight saving since 1951.
Mountain Time is UTC−7 in winter (MST) and UTC−6 in summer (MDT) for Denver, Salt Lake City and Calgary. Most of Arizona stays on MST (UTC−7) all year.