KST to GMT Converter
Convert time between Korea Standard Time (KST) and Greenwich Mean Time (GMT)
Korea Standard Time (KST)
Greenwich Mean Time (GMT)
Time Difference
Greenwich Mean Time (GMT) is 0 hours ahead of Korea Standard Time (KST)
Select Date
Select Time
Quick Reference
| KST | GMT |
|---|---|
| 11:00 | 03:00 |
| 13:00 | 05:00 |
| 15:00 | 07:00 |
| 17:00 | 09:00 |
| 19:00 | 11:00 |
| 21:00 | 13:00 |
| 23:00 | 15:00 |
| 01:00 | 17:00 |
| 03:00 | 19:00 |
| 05:00 | 21:00 |
| 07:00 | 23:00 |
| 09:00 | 01:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
About KST to GMT Time Conversion
Converting time from Korea Standard Time (KST) to Greenwich Mean Time (GMT) is essential for South Korea-UK coordination during the British winter, and useful for any global scheduling that uses GMT as a reference. KST is UTC+9 and GMT is UTC+0, making GMT 9 hours behind KST. South Korea does not observe daylight saving time.
The UK switches to BST (UTC+1) from late March to late October, dropping the gap to 8 hours. This converter uses the IANA timezone database (Europe/London) to apply the correct offset automatically based on the date you pick.
Common Use Cases for KST to GMT Conversion
Business & Work
- Scheduling calls between Korean teams and London or Dublin offices during the UK winter
- Coordinating with global teams that use GMT as a reference timezone
- Planning end-of-day handoffs from Seoul into the start of a UK workday
Personal & Travel
- Keeping in touch with family or friends in the UK or Ireland
- Planning travel from South Korea to London, Dublin, or Edinburgh
- Scheduling virtual events that span Asia and Europe
Time Zone Information
Korea Standard Time (KST)
- UTC Offset: UTC+9 (no DST observed)
- IANA Timezone: Asia/Seoul
- Daylight Saving: South Korea does not observe daylight saving time
- Major Cities: Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, Jeju
- Coverage: All of South Korea
Greenwich Mean Time (GMT)
- UTC Offset: UTC+0 (UTC+1 BST during DST)
- IANA Timezone: Europe/London
- Daylight Saving: Last Sunday in March to Last Sunday in October (UK uses BST)
- Major Cities: London, Dublin, Lisbon, Reykjavik
- Coverage: United Kingdom, Ireland, Portugal, Iceland, and reference standard for global timekeeping
Quick Reference: KST to GMT
Remember: GMT is 9 hours behind KST during the British winter; during DST the UK uses BST and the gap drops to 8 hours
Frequently Asked Questions
What is the time difference between KST and GMT?
Korea Standard Time (KST) is UTC+9, while Greenwich Mean Time (GMT) is UTC+0. GMT is 9 hours behind KST, so when it is 12:00 PM in Seoul, it is 3:00 AM in London.
How does GMT differ from BST in this conversion?
GMT applies in the UK during winter (late October to late March). In summer, the UK switches to British Summer Time (BST, UTC+1), which is 8 hours behind KST. Korea does not observe DST, so the seasonal change is entirely on the UK side.
How can I quickly convert KST to GMT?
Subtract 9 hours from the Korean time. For example, 5 PM KST is 8 AM GMT, and 9 PM KST is 12 PM GMT.
What are the best times to schedule KST to GMT business calls?
Live overlap is workable. The best window is late afternoon Korea (5–7 PM KST), which is 8–10 AM GMT — the start of a UK workday meeting the end of a Seoul workday.
Which regions and cities use GMT?
GMT (UTC+0) is used by the United Kingdom (in winter), Ireland, Portugal, Iceland, and various West African countries. Major cities include London, Dublin, Lisbon, and Reykjavik. GMT also serves as a global reference timezone for aviation, broadcasting, and IT.
Which regions use KST?
KST (UTC+9) is used by all of South Korea. Major cities include Seoul, Busan, Incheon, Daegu, Daejeon, Gwangju, and Jeju. South Korea does not observe daylight saving time.
Pro Tips
- • GMT is 9 hours behind KST — subtract 9 hours from Korean time.
- • GMT applies in the UK only in winter; during British Summer Time the gap drops to 8 hours.
- • Korea never observes DST, so all seasonal change is on the UK side.
- • For live calls, late-afternoon Korea (5–7 PM KST) lines up with the start of a UK morning (8–10 AM GMT).
- • GMT is widely used as a reference timezone in aviation, broadcasting, and global IT operations — convenient for cross-team scheduling.
- • For recurring meetings, fix the UK local time and let KST shift automatically with GMT/BST transitions.