21:00 UTC to JST
Convert an exact time type it — no sliders
Conversion runs in your browser against the same IANA rules the server uses, so it keeps working offline and nothing you type is sent anywhere.
Daylight saving right now
Japan Standard Time
Asia/Tokyo is currently on JST (UTC+09:00).
no clock change scheduled — this zone is fixed at UTC+09:00
Japan Standard Time is UTC+9 with no daylight saving — Japan has not observed DST since 1951, so the offset is safe to hard-code.
Coordinated Universal Time
UTC is on UTC (UTC+00:00).
no clock change scheduled — fixed at UTC+00:00
UTC is the reference clock every other offset is quoted against. It has no daylight saving and never shifts.
Best time to call green = 09:00–18:00 on both sides
No overlap inside a 09:00–18:00 day on both sides. Someone has to take an early or late slot — the table below shows exactly which hours are least bad.
UTC to JST, hour by hour 13 August 2026 · every row is a permalink
| UTC | JST | 12-hour | Day | Permalink |
|---|---|---|---|---|
| 00:00 | 09:00 JST | 9:00 AM | same day | 00:00 → |
| 01:00 | 10:00 JST | 10:00 AM | same day | 01:00 → |
| 02:00 | 11:00 JST | 11:00 AM | same day | 02:00 → |
| 03:00 | 12:00 JST | 12:00 PM | same day | 03:00 → |
| 04:00 | 13:00 JST | 1:00 PM | same day | 04:00 → |
| 05:00 | 14:00 JST | 2:00 PM | same day | 05:00 → |
| 06:00 | 15:00 JST | 3:00 PM | same day | 06:00 → |
| 07:00 | 16:00 JST | 4:00 PM | same day | 07:00 → |
| 08:00 | 17:00 JST | 5:00 PM | same day | 08:00 → |
| 09:00 | 18:00 JST | 6:00 PM | same day | 09:00 → |
| 10:00 | 19:00 JST | 7:00 PM | same day | 10:00 → |
| 11:00 | 20:00 JST | 8:00 PM | same day | 11:00 → |
| 12:00 | 21:00 JST | 9:00 PM | same day | 12:00 → |
| 13:00 | 22:00 JST | 10:00 PM | same day | 13:00 → |
| 14:00 | 23:00 JST | 11:00 PM | same day | 14:00 → |
| 15:00 | 00:00 JST | 12:00 AM | next day | 15:00 → |
| 16:00 | 01:00 JST | 1:00 AM | next day | 16:00 → |
| 17:00 | 02:00 JST | 2:00 AM | next day | 17:00 → |
| 18:00 | 03:00 JST | 3:00 AM | next day | 18:00 → |
| 19:00 | 04:00 JST | 4:00 AM | next day | 19:00 → |
| 20:00 | 05:00 JST | 5:00 AM | next day | 20:00 → |
| 21:00 | 06:00 JST | 6:00 AM | next day | 21:00 → |
| 22:00 | 07:00 JST | 7:00 AM | next day | 22:00 → |
| 23:00 | 08:00 JST | 8:00 AM | next day | 23:00 → |