Turn a Korea Standard Time reading into Coordinated Universal Time. The panels show both clocks live, and the roller lets you line up any KST time against its UTC equivalent.
Korea Standard Time
Coordinated Universal Time
US Eastern Time
THE CLOCKS ABOVE ALWAYS SHOW THE LIVE CURRENT TIME. THE ROLLER BELOW IS A LOOKUP TOOL — ROTATING IT NEVER CHANGES THEM.
KST is 9 hours ahead of UTC
ET is 4 hours behind UTC
South Korea is 13 hours ahead of United States (Eastern)
| KST | 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 |
Korea Standard Time is the local clock in South Korea. 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.
Korea Standard Time covers the whole country and shares its offset with Tokyo.
Subtract the current offset shown in the offset panel from the local KST 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.
KST has no daylight saving changes, so the offset to UTC is stable all year. It is still calculated live from the Asia/Seoul 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.
South Korea does not observe daylight saving time. KST is always UTC +09:00, the same as Japan.