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BlogHow it works

KST to GMT Converter

Enter a Seoul time to read it in GMT, the UTC+0 reference used for logs, flights and broadcasts. Korea has no daylight saving, so the gap never moves.

Korea Standard Time

KSTKorea Standard Time

GMTGreenwich Mean Time

––:––

How far ahead of GMT is Korea?

Seoul is 9 hours ahead of GMT all year. Subtract 9 hours from a Korea time; before 9:00 AM in Seoul the GMT date is the day before.

KST
UTC+9, no DST
GMT
UTC+0, fixed
UK summer
BST, UTC+1

KST to GMT conversion table

KST timeGMT time
12:00 AM3:00 PM−1 previous day
1:00 AM4:00 PM−1 previous day
2:00 AM5:00 PM−1 previous day
3:00 AM6:00 PM−1 previous day
4:00 AM7:00 PM−1 previous day
5:00 AM8:00 PM−1 previous day
6:00 AM9:00 PM−1 previous day
7:00 AM10:00 PM−1 previous day
8:00 AM11:00 PM−1 previous day
9:00 AM12:00 AM
10:00 AM1:00 AM
11:00 AM2:00 AM
12:00 PM3:00 AM
1:00 PM4:00 AM
2:00 PM5:00 AM
3:00 PM6:00 AM
4:00 PM7:00 AM
5:00 PM8:00 AM
6:00 PM9:00 AM
7:00 PM10:00 AM
8:00 PM11:00 AM
9:00 PM12:00 PM
10:00 PM1:00 PM
11:00 PM2:00 PM
All 24 Seoul hours with the GMT time. −1 marks a GMT time on the previous calendar day.

GMT here means UTC+0

This converter treats GMT as the fixed UTC+0 scale, which reads the same as Coordinated Universal Time from the BIPM. It does not follow the UK's summer clock. Korea Standard Time is UTC+9 throughout the year, so the conversion is a plain subtraction of nine hours.

Typical uses are aviation and shipping schedules, satellite and weather data, and server logs that record events in UTC while users read them in Seoul. A log line stamped 23:30 GMT, for example, happened at 8:30 AM the next morning in Korea.

Talking to someone in the UK

If a British colleague says GMT in summer, they usually mean the London clock. The UK switches to BST on the last Sunday in March and back on the last Sunday in October (GOV.UK). During BST, 9:00 AM in London is 5:00 PM in Seoul; in winter it is 6:00 PM.

The London clock follows those changes for you. The Seoul clock shows Korea's current time.

What makes it easy

  • Seoul's evening (5:00–7:00 PM) meets the London morning.
  • No Korean clock changes to track.
  • The same result holds for Tokyo: JST to GMT.

What to watch

  • The UK summer change shifts London calls by an hour.
  • A London afternoon is already late night in Seoul.
  • Deadlines in GMT often fall on the next calendar day in Korea.

KST to GMT questions

What is the time difference between KST and GMT?

Korea Standard Time is 9 hours ahead of GMT on every date.

What is 3:00 PM in Seoul in GMT?

3:00 PM KST is 6:00 AM GMT the same day.

How many hours ahead of London is Seoul?

9 hours in the UK winter and 8 hours while the UK is on British Summer Time, from late March to late October.

Does Korea ever change its clocks?

No. South Korea has stayed on UTC+9 without summer time since 1988.

Is KST the same as JST?

They have the same offset, UTC+9, so Seoul and Tokyo always show the same time.