GMT vs KST Time Difference
See the 9-hour difference between Greenwich Mean Time and Korea Standard Time, check DST impacts, and find the best overlap for meetings.
GMT to KST Difference
Greenwich Mean Time is UTC+0 and Korea Standard Time is UTC+9, so KST is 9 hours ahead of GMT year-round. Use the live comparison table to see the current hour difference instantly.
DST Effects and Changes
Korea Standard Time does not observe daylight saving time, while GMT remains UTC+0 as standard time. The page tracks seasonal shifts automatically using the IANA timezone database when related regions switch offsets.
Best Meeting Time Windows
Find overlapping work hours with the visual grid, compare hour-by-hour slots, and pick practical meeting times between GMT and KST. Export selected times with ICS download or send them to Google Calendar and Gmail.
How to Find the Time Difference Between GMT and KST
Open the GMT vs KST converter: Visit https://www.xconvert.com/time-converter/gmt-vs-kst to see Greenwich Mean Time and Korea Standard Time lined up on a visual 24-hour comparison grid. This view is useful when you are scheduling a call between the United Kingdom and South Korea, planning support coverage across Europe and East Asia, or checking whether a London-based meeting will land during business hours in Seoul.
Add comparison cities with the + Add City button: Click + Add City and search for places that matter to your workflow, such as London, Seoul, or Pyongyang for government, logistics, manufacturing, media, or technology coordination. You can also add another GMT location such as Accra or Reykjavik if your team spans multiple countries that use Greenwich Mean Time and you need to compare one KST schedule against several offices at once.
Drag across the grid to select a meeting window: Click Select, then drag across the colored timeline on the GMT row to highlight a time range in purple; use the left and right handles to resize it or drag the center to move the whole block. For example, selecting 9:00 GMT to 12:00 GMT shows 18:00 KST to 21:00 KST, which helps confirm that a late-morning GMT call becomes an evening meeting in Korea; selecting 15:00 GMT shows 0:00 KST the next day, which is important when avoiding midnight handoffs for Seoul teams.
Export and share the selected time: Once a range is selected, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is practical for sending a confirmed meeting slot to a distributed team, dropping the time into an email for a Korean supplier, or sharing a calendar-ready event with colleagues so everyone sees the meeting in their own local time automatically.
GMT vs KST Offset Explained
Greenwich Mean Time is UTC+0, and Korea Standard Time is UTC+9. That means KST is 9 hours ahead of GMT, and equivalently GMT is 9 hours behind KST. In practical terms, 9:00 GMT = 18:00 KST and 12:00 GMT = 21:00 KST, so a normal daytime slot in GMT often lands in the Korean evening.
The time gap becomes even more important later in the day. 15:00 GMT = 0:00 KST (next day) and 18:00 GMT = 3:00 KST (next day), so afternoon work in GMT can already be the next calendar day in Korea. This matters for contract deadlines, software deployment windows, customer support escalation, and flight or shipment cutoffs that depend on the local date as well as the local hour.
Seasonal changes affect this comparison because GMT is a standard-time abbreviation, and its daylight saving counterpart is BST. KST does not observe DST, so Korea stays on the same time year-round while locations using GMT may switch to British Summer Time in part of the year. If you are coordinating with the United Kingdom, it is important to distinguish between true GMT periods and BST periods, because the label on the schedule changes even though Korea remains on KST throughout the year.
GMT is used across a wide set of countries, including Burkina Faso, Gambia, Ghana, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Saint Helena, Sao Tome and Principe, Senegal, Sierra Leone, Togo, and the United Kingdom. KST is used in North Korea and South Korea. That makes this comparison especially relevant for trade, shipping, media distribution, embassy coordination, and remote work linking West Africa, the British Isles, and the Korean Peninsula.
Working Across GMT and KST Business Hours
A 9-hour lead means the overlap between standard office hours is limited and usually favors early GMT mornings with late KST afternoons or evenings. For example, 9:00 GMT = 18:00 KST, which can still work for end-of-day calls in Seoul, while 12:00 GMT = 21:00 KST is already late for many teams. This makes morning GMT scheduling the most practical option for live meetings involving Korean partners.
For remote teams, this pattern often affects engineering handoffs, procurement updates, and customer communication. A product manager in a GMT location can review work at the start of the day and pass decisions to a Seoul-based development or operations team before their evening ends. By contrast, a late GMT meeting request can push Korean participants into the next day, as shown by 15:00 GMT = 0:00 KST (next day).
Travel and logistics planning also benefit from understanding the next-day rollover. If a shipment release, airport transfer, or hotel check-in is discussed in GMT during the afternoon, the corresponding Korean time may already be after midnight. That can change which local business day applies for customs processing, warehouse staffing, or arrival coordination in South Korea.
Where GMT and KST Are Commonly Used
GMT is associated with countries in West Africa, the British Isles, and parts of the Atlantic region, while KST is the standard time in North Korea and South Korea. This means the comparison appears frequently in international trade, education, media licensing, and multinational project management where organizations in London, Accra, Reykjavik, or Dublin need to coordinate with Seoul.
South Korea’s economy makes KST especially important for sectors such as electronics, semiconductors, automotive manufacturing, gaming, and shipping. Teams working with Korean companies often need to align factory updates, procurement approvals, or partner calls with Korean business hours, and the 9-hour difference shapes when those conversations can realistically happen. A GMT-based company that waits until late afternoon may miss the Korean business day entirely.
The GMT side is broader because multiple countries use the same standard offset. That can simplify regional scheduling for organizations operating across Ghana, Senegal, Sierra Leone, and the United Kingdom during periods when GMT is in effect. When those organizations need to connect with Korea, using a visual comparison grid helps quickly identify whether a proposed slot stays within evening hours in KST or spills into the next calendar day.
Frequently Asked Questions
What is the time difference between GMT and KST?
Korea Standard Time is 9 hours ahead of Greenwich Mean Time. Put another way, GMT is 9 hours behind KST. A simple example is 9:00 GMT = 18:00 KST, which shows how a morning hour in GMT becomes an early evening hour in Korea.
Is KST always 9 hours ahead of GMT?
Yes. KST is UTC+9 and does not observe DST, so it remains fixed throughout the year. GMT is UTC+0 as a standard-time abbreviation, which means the GMT-to-KST comparison stays at 9 hours whenever GMT is the time standard being used.
Does Korea use daylight saving time?
No. Korea Standard Time does not observe DST, so clocks in South Korea and North Korea do not shift seasonally under KST. This consistency is useful for long-term planning because Korean local time stays stable even when some GMT-related schedules may change labels seasonally due to the use of BST in places such as the United Kingdom.
Why does my GMT to Korea meeting sometimes seem to fall on the next day?
The date changes because Korea is 9 hours ahead of GMT, so later GMT times can cross midnight in KST. For example, 15:00 GMT = 0:00 KST (next day) and 18:00 GMT = 3:00 KST (next day). This is especially important for deadlines, support coverage, and calendar invites, because the Korean participant may see the meeting on the following date.
What are the best GMT hours for calling South Korea?
The most practical GMT hours are usually earlier in the GMT day because Korea is already far ahead. 9:00 GMT = 18:00 KST is often workable for business calls, while 12:00 GMT = 21:00 KST is already late in the evening for many offices. Once you reach 15:00 GMT, it is 0:00 KST the next day, which is generally unsuitable for routine meetings.
Which countries use GMT and which use KST?
GMT is used in Burkina Faso, Gambia, Ghana, Guernsey, Guinea, Guinea-Bissau, Iceland, Ireland, Isle of Man, Ivory Coast, Jersey, Liberia, Mali, Mauritania, Saint Helena, Sao Tome and Principe, Senegal, Sierra Leone, Togo, and the United Kingdom. KST is used in North Korea and South Korea. This makes the comparison relevant for organizations connecting the Korean Peninsula with the UK, Ireland, Iceland, and several West African markets.
Is GMT the same as UK time all year?
Not all year. GMT is the United Kingdom’s standard-time reference, but its daylight saving counterpart is BST. That distinction matters when scheduling with Korea, because KST does not observe DST, so Korean time stays constant while UK time may be labeled differently depending on the season.
How do I quickly convert GMT to KST without doing mental math?
Use the visual comparison grid to line up the two rows and drag across the GMT hours you are considering. The examples make the pattern easy to remember: 9:00 GMT = 18:00 KST, 12:00 GMT = 21:00 KST, 15:00 GMT = 0:00 KST (next day), and 18:00 GMT = 3:00 KST (next day). This is faster and less error-prone when you are booking calls, sharing deadlines, or coordinating teams across different calendar dates.