UTC to KST Converter (Coordinated Universal Time to Korea Time)

KST is 9 hours ahead of UTC.

Korea Standard Time is defined as nine hours ahead of Coordinated Universal Time. Since neither UTC nor KST changes with the seasons, the rule is the simplest one in time zones: add 9 hours to the UTC reading to get the Korean one. When the result passes 24:00, the Korean date is the next one.

People need it when they read server logs, API responses and calendar files that store UTC, when they set up a scheduled job in a Korean data center, or when a global announcement is quoted in UTC and they want the local hour in Seoul.

How to use this tool

1. Pick a date and time in UTC. The date matters when daylight saving time is in force.
2. Read the matching time in KST, with both UTC offsets.
3. Use "Use current time" for now, or the tables below for a quick look.

Formula

KST time = UTC time − (UTC UTC offset) + (KST UTC offset)

The converter looks up both UTC offsets for the actual instant in the saved IANA time zone rules, so daylight saving changes are included automatically.

Example

Worked with the saved rules:

9:00 AM UTC on March 2, 2026 = 6:00 PM KST

6:30 PM UTC on August 3, 2026 = 3:30 AM KST (next day)

Time difference through the year

The difference depends on the date when either place moves its clocks. These are the offsets on two reference days, from the saved IANA rules:

Clock changes in 2026

Coordinated Universal Time and Korea Standard Time do not change clocks in this year, so the difference stays the same all year.

UTC to KST time table

Each hour in Coordinated Universal Time with the matching Korea Standard Time time.

KST to UTC time table

Each hour in Korea Standard Time with the matching Coordinated Universal Time time.

Hours that work in both places

Hours (on the January reference day) that fall between 8:00 AM and 8:00 PM in both UTC and KST:

Reading timestamps in logs and APIs

Many systems write times as ISO 8601 or RFC 3339 strings. A trailing Z means UTC, and +09:00 means Korea Standard Time. The timestamp 2026-03-02T00:00:00Z is the same moment as 2026-03-02T09:00:00+09:00, and 2026-03-02T15:00:00Z is midnight at the start of March 3 in Seoul.

A date that is filtered in UTC will therefore differ from a date filtered in Seoul for nine hours of every day. A daily report that closes at 00:00 KST actually cuts at 15:00 UTC the day before, and teams that mix the two will see numbers that seem to leak from one day to the next.

UTC is not a time zone with a summer

UTC is the time standard kept by the BIPM from the atomic clocks of national laboratories, and it has no daylight saving time. Leap seconds, the occasional one-second adjustments, are added to UTC, not to the zone offsets; the most recent was added on December 31, 2016.

UTC and KST are both steady, so a table for one day holds for the whole year, and the hour table below does not need a separate summer column.