JST to UTC converter
UTC is 9 hours behind Japan Standard Time year-round: Japan Standard Time runs at UTC+9 and UTC at UTC+0. To convert JST to UTC, subtract 9 hours from the JST time. Neither zone observes daylight saving time, so the offsets hold on every date.
Japan Standard Time runs at UTC+9, UTC at UTC+0.
JST to UTC conversion table
Every hour of the day converted. One column is enough here: the gap between the two zones is the same in winter and summer.
| Japan Standard Time (JST) | UTC (UTC) |
|---|---|
| 00:00 12:00 AM | 15:00 3:00 PM previous day |
| 01:00 1:00 AM | 16:00 4:00 PM previous day |
| 02:00 2:00 AM | 17:00 5:00 PM previous day |
| 03:00 3:00 AM | 18:00 6:00 PM previous day |
| 04:00 4:00 AM | 19:00 7:00 PM previous day |
| 05:00 5:00 AM | 20:00 8:00 PM previous day |
| 06:00 6:00 AM | 21:00 9:00 PM previous day |
| 07:00 7:00 AM | 22:00 10:00 PM previous day |
| 08:00 8:00 AM | 23:00 11:00 PM previous day |
| 09:00 9:00 AM | 00:00 12:00 AM |
| 10:00 10:00 AM | 01:00 1:00 AM |
| 11:00 11:00 AM | 02:00 2:00 AM |
| 12:00 12:00 PM | 03:00 3:00 AM |
| 13:00 1:00 PM | 04:00 4:00 AM |
| 14:00 2:00 PM | 05:00 5:00 AM |
| 15:00 3:00 PM | 06:00 6:00 AM |
| 16:00 4:00 PM | 07:00 7:00 AM |
| 17:00 5:00 PM | 08:00 8:00 AM |
| 18:00 6:00 PM | 09:00 9:00 AM |
| 19:00 7:00 PM | 10:00 10:00 AM |
| 20:00 8:00 PM | 11:00 11:00 AM |
| 21:00 9:00 PM | 12:00 12:00 PM |
| 22:00 10:00 PM | 13:00 1:00 PM |
| 23:00 11:00 PM | 14:00 2:00 PM |
How the JST to UTC conversion works
Converting JST to UTC means taking a wall-clock time in Japan Standard Time (JST, UTC+9) and expressing the same instant in UTC (UTC, UTC+0). The arithmetic is one step: subtract 9 hours from any JST time, and it holds on every date of the year. Applying the gap pushes part of the day onto a different calendar date — the table below marks every row that shifts. In code, store the instant in UTC and convert with the IANA identifiers Asia/Tokyo and Etc/UTC, never with the abbreviations. One note on the source label: JST has been fixed at UTC+9 since 1951 and shares its offset with Korea Standard Time. On the target label: UTC is the fixed reference every other offset is measured against, and it never shifts. IANA identifiers carry the full offset history of a region, including every daylight saving transition ever legislated, which is why databases, schedulers, and APIs should store them.
Best time for meetings between JST and UTC
Working hours are taken as 09:00–18:00 in each zone. The window in force depends on the date, so both halves of the year are listed where they differ.
UTC, year-round
The two working days meet at a single point: 6:00 PM JST is 9:00 AM UTC, exactly when the UTC working day begins. A call of any real length needs one side to start early or finish late.
Daylight saving time: which side moves
Neither Japan Standard Time nor UTC observes daylight saving time, so the difference stays at 9 hours year-round. There is no transition weekend to plan around, and neither zone has a summer abbreviation.
- Japan Standard Time
- Asia/Tokyo
- JST — UTC+9
- UTC
- Etc/UTC
- UTC — UTC+0
Frequently asked questions
What is the time difference between JST and UTC?
UTC runs 9 hours behind Japan Standard Time on every date of the year. In offset terms, Japan Standard Time sits at UTC+9 and UTC at UTC+0. So 9:00 AM JST is 12:00 AM UTC. The hour-by-hour table on this page lists the conversion for all 24 hours so you do not have to do the arithmetic.
Does the JST to UTC difference change with daylight saving time?
The difference is fixed at 9 hours. Neither Japan Standard Time nor UTC observes daylight saving time, so no date in the calendar changes the conversion. Convert against the IANA rules for the exact date rather than a remembered offset. Both zones are handled here through their IANA identifiers, Asia/Tokyo and Etc/UTC, which encode the transitions.
What time is 9 am JST in UTC?
9:00 AM JST is 12:00 AM in UTC, and it stays that way all year because the two zones stay 9 hours apart. The rule is the same one the whole page runs on: subtract 9 hours from any JST time. Check the hour-by-hour table for any other starting hour, including the rows that land on the previous or next calendar day.
What do JST and UTC stand for?
JST stands for Japan Standard Time. UTC stands for Coordinated Universal Time. Both are display labels rather than rules: the offsets behind them come from the IANA identifiers Asia/Tokyo and Etc/UTC. JST has been fixed at UTC+9 since 1951 and shares its offset with Korea Standard Time. UTC is the fixed reference every other offset is measured against, and it never shifts.
Related conversions
Need more than two zones at once? The full timezone converter shows a single moment across up to six IANA timezones, for any date you choose.