Compare GMT and KST
See the 9-hour difference between GMT and KST, check overlap hours, and plan calls or meetings across the UK and South Korea.
GMT-KST Time Difference
KST is 9 hours ahead of GMT year-round, with GMT at UTC+0 and Korea Standard Time at UTC+9. Use this page to quickly compare current hours and daily time alignment.
No DST Shift Impact
Neither GMT nor KST observes daylight saving time in standard usage, so the 9-hour gap stays consistent. Time calculations update automatically using IANA timezone database rules.
Best Meeting Time Windows
Review visual overlap hours, hour-by-hour comparison tables, and scheduling windows for GMT and KST. Export meeting times with ICS download or send to Google Calendar and Gmail.
How to Find the Time Difference Between GMT and KST
Open the GMT vs KST page: Visit
https://www.xconvert.com/time-converter/gmt-vs-kstto load a visual comparison grid with GMT and KST already shown as separate rows. This view is useful when you are scheduling a call between the United Kingdom and South Korea, coordinating a game launch across London and Seoul, or checking whether a support handoff from a GMT-based team will land during Korean business hours.Add comparison cities with + Add City: Click + Add City and search for cities that matter to your workflow, such as London, Seoul, and Busan for media, finance, shipping, and technology coordination. This is especially practical for teams working with South Korean electronics, automotive, or gaming companies, where meetings often involve a GMT-facing office and a KST-based operations or engineering team.
Drag across the grid to select a meeting window: Click Select if needed, then drag across the colored timeline on the GMT row to highlight a range in purple, such as 9:00 to 12:00 GMT, which corresponds to 18:00 to 21:00 KST. You can also test a later slot like 15:00 GMT = 0:00 KST (next day) or 18:00 GMT = 3:00 KST (next day), which quickly shows why an afternoon meeting in GMT can push into midnight or early morning in Korea.
Resize, move, and export the selected time: Drag the left or right purple handles to fine-tune the range, or drag the center of the selection to shift the entire block earlier or later until it fits both sides. Once selected, use ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link to send the final time to clients, suppliers, or remote teammates so everyone receives the meeting in their own local time without manual conversion.
GMT vs KST Offset Explained
GMT is UTC+0, while KST is UTC+9, so KST is 9 hours ahead of GMT. In practical terms, that means 9:00 GMT = 18:00 KST and 12:00 GMT = 21:00 KST, which places a late-morning GMT meeting into the Korean evening. This matters for cross-border work in finance, manufacturing, gaming, logistics, and customer support, where teams in the United Kingdom or West Africa may need to coordinate with offices or partners in South Korea.
The time gap becomes more difficult later in the GMT day because 15:00 GMT = 0:00 KST (next day) and 18:00 GMT = 3:00 KST (next day). For real scheduling, this means GMT afternoon calls often spill into the next calendar day in Korea, which can affect product launches, overnight monitoring, freight coordination, and executive meetings with Seoul-based stakeholders.
GMT is a standard-time abbreviation, and its DST counterpart is IST. KST does not observe DST, so Korea stays on the same clock year-round. That means seasonal changes mainly affect the GMT side when regions using GMT shift to their daylight-saving counterpart, which is why it is important to confirm whether your contact is specifically on GMT or on a seasonal local time in places such as the United Kingdom or Ireland.
GMT is used across a wide range 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 geographic spread makes GMT relevant not just for London-based business, but also for NGOs, commodity trade, aviation planning, and public-sector coordination across West Africa and the North Atlantic.
Frequently Asked Questions
What is the time difference between GMT and KST?
KST is 9 hours ahead of GMT. A simple example is 9:00 GMT = 18:00 KST, which means a standard morning slot in GMT lands in the early evening in Korea. This gap is large enough that teams usually need to choose between a GMT morning meeting or a Korea morning meeting, rather than trying to fit both into normal office hours.
Is Korea ahead of GMT or behind it?
Korea is ahead of GMT. Specifically, KST is UTC+9 while GMT is UTC+0, so South Korea and North Korea run 9 hours later on the clock than GMT locations. That is why 12:00 GMT = 21:00 KST, making lunchtime in GMT already late evening in Korea.
Does KST observe daylight saving time?
No, KST does not observe DST. Korea stays on the same time standard throughout the year, which makes recurring scheduling more predictable for teams working with Seoul, Incheon, or Busan. The seasonal complication comes from the GMT side, because GMT is a standard-time abbreviation and its DST counterpart is IST.
Why does the GMT to KST difference matter for business meetings?
The 9-hour gap strongly shapes when teams can meet without pushing one side outside normal work hours. For example, 9:00 GMT = 18:00 KST is often workable for an end-of-day Korea call, but 15:00 GMT = 0:00 KST (next day) is usually too late for a routine meeting. This is especially relevant for industries with active UK-Korea links, including automotive supply chains, semiconductors, shipbuilding, entertainment, esports, and consumer electronics.
What is the best GMT time for a call with South Korea?
A GMT morning slot is usually the most practical because it maps to Korea’s evening rather than midnight. Using the common examples, 9:00 GMT = 18:00 KST and 12:00 GMT = 21:00 KST, so those windows can still work for same-day discussions. Once you move to 15:00 GMT = 0:00 KST (next day), the meeting becomes much harder for Korean participants unless it is urgent or tied to shift-based operations.
Why does 15:00 GMT show as the next day in KST?
Because KST is 9 hours ahead of GMT, adding that difference pushes 15:00 GMT to 0:00 KST, which is midnight on the following calendar day. The same pattern continues later, so 18:00 GMT = 3:00 KST (next day). This next-day rollover is important when booking flights, sending calendar invites, planning release windows, or arranging overnight technical support.
Is GMT the same as local UK time all year?
No, not all year. GMT is a standard-time abbreviation, and its DST counterpart is IST, so the local clock can change seasonally in places that use GMT in part of the year, including the United Kingdom and Ireland. For scheduling with Korea, that distinction matters because KST remains fixed while the GMT side may switch to its daylight-saving counterpart depending on the season.
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 means GMT-to-KST conversion is relevant not only for UK-Korea communication, but also for trade, diplomacy, development work, and logistics between Korea and GMT-based countries in West Africa and the North Atlantic region.