Turn a Japan Standard Time reading into Coordinated Universal Time. The panels show both clocks live, and the roller lets you line up any JST time against its UTC equivalent.
Japan Standard Time
Coordinated Universal Time
United Kingdom Time
THE CLOCKS ABOVE ALWAYS SHOW THE LIVE CURRENT TIME. THE ROLLER BELOW IS A LOOKUP TOOL — ROTATING IT NEVER CHANGES THEM.
JST is 9 hours ahead of UTC
GMT/BST is 1 hour ahead of UTC
Japan is 8 hours ahead of United Kingdom
| JST | UTC | Date |
|---|---|---|
| 09:00 | 00:00 | Same day |
| 10:00 | 01:00 | Same day |
| 11:00 | 02:00 | Same day |
| 12:00 | 03:00 | Same day |
| 13:00 | 04:00 | Same day |
| 14:00 | 05:00 | Same day |
| 15:00 | 06:00 | Same day |
| 16:00 | 07:00 | Same day |
| 17:00 | 08:00 | Same day |
| 18:00 | 09:00 | Same day |
| 19:00 | 10:00 | Same day |
| 20:00 | 11:00 | Same day |
| 21:00 | 12:00 | Same day |
| 22:00 | 13:00 | Same day |
| 23:00 | 14:00 | Same day |
| 00:00 | 15:00 | Previous day in UTC |
| 01:00 | 16:00 | Previous day in UTC |
| 02:00 | 17:00 | Previous day in UTC |
| 03:00 | 18:00 | Previous day in UTC |
| 04:00 | 19:00 | Previous day in UTC |
| 05:00 | 20:00 | Previous day in UTC |
| 06:00 | 21:00 | Previous day in UTC |
| 07:00 | 22:00 | Previous day in UTC |
| 08:00 | 23:00 | Previous day in UTC |
Japan Standard Time is the local clock in Japan. Converting it to UTC removes the local offset so the time can be shared with anyone in the world without ambiguity — which is exactly why UTC is used for servers, aviation and international scheduling.
Japan Standard Time applies to the entire country, including Okinawa, and is aligned to the 135° E meridian near Akashi.
Subtract the current offset shown in the offset panel from the local JST time. If the result goes below 00:00, UTC is still on the previous date. Use the roller to read the pairing directly instead of doing the arithmetic.
JST has no daylight saving changes, so the offset to UTC is stable all year. It is still calculated live from the Asia/Tokyo IANA database rather than hard-coded.
Early-morning or late-night local times frequently sit on a different UTC date. The converter labels every selection as SAME DAY, NEXT DAY or PREVIOUS DAY so a deadline written in UTC is never off by 24 hours.
Japan has not observed daylight saving time since the late 1940s, so JST is a constant UTC +09:00.