Time zone comparison
Greenwich Mean Time (GMT, UTC+00:00) vs Korea Standard Time (KST, UTC+09:00). Right now GMT is 9h behind KST. GMT is used in United Kingdom (winter), West Africa, Iceland while KST covers Seoul, Busan and Incheon. Use the 24-hour grid below to find a meeting slot both sides will tolerate.
Each row is one hour. Green rows are when both sides are inside 9 AM to 5 PM.
| Hour | GMT (Greenwich Mean Time) | KST (Korea Standard Time) | Overlap |
|---|---|---|---|
| 12 AM | 00:00Thu | 09:00Thu | KST only |
| 1 AM | 01:00Thu | 10:00Thu | KST only |
| 2 AM | 02:00Thu | 11:00Thu | KST only |
| 3 AM | 03:00Thu | 12:00Thu | KST only |
| 4 AM | 04:00Thu | 13:00Thu | KST only |
| 5 AM | 05:00Thu | 14:00Thu | KST only |
| 6 AM | 06:00Thu | 15:00Thu | KST only |
| 7 AM | 07:00Thu | 16:00Thu | KST only |
| 8 AM | 08:00Thu | 17:00Thu | No overlap |
| 9 AM | 09:00Thu | 18:00Thu | GMT only |
| 10 AM | 10:00Thu | 19:00Thu | GMT only |
| 11 AM | 11:00Thu | 20:00Thu | GMT only |
| 12 PM | 12:00Thu | 21:00Thu | GMT only |
| 1 PM | 13:00Thu | 22:00Thu | GMT only |
| 2 PM | 14:00Thu | 23:00Thu | GMT only |
| 3 PM | 15:00Thu | 00:00Fri | GMT only |
| 4 PM | 16:00Thu | 01:00Fri | GMT only |
| 5 PM | 17:00Thu | 02:00Fri | No overlap |
| 6 PM | 18:00Thu | 03:00Fri | No overlap |
| 7 PM | 19:00Thu | 04:00Fri | No overlap |
| 8 PM | 20:00Thu | 05:00Fri | No overlap |
| 9 PM | 21:00Thu | 06:00Fri | No overlap |
| 10 PM | 22:00Thu | 07:00Fri | No overlap |
| 11 PM | 23:00Thu | 08:00Fri | No overlap |
Greenwich Mean Time (GMT) sits at UTC+00:00 today, while Korea Standard Time (KST) is at UTC+09:00. The current gap is 9 hours, with GMT behind KST. In practical terms, if your morning starts at 9 AM in United Kingdom (winter), West Africa, Iceland, your counterpart in Seoul is seeing 18:00 on their own watch at that exact moment.
GMT is the working clock for United Kingdom (winter), West Africa, Iceland. GMT and UTC agree to the second in practice. The UK uses GMT in winter and BST in summer. KST covers Seoul, Busan and Incheon. If your team is split between these two regions, the table above is the quickest way to spot the daily overlap window without doing the offset arithmetic in your head.
Neither GMT nor KST observes daylight saving in the modern era, which is unusual and convenient: the gap between the two zones stays the same in January and in July. You can quote the offset once and forget about it.
Common scheduling traps are easy to avoid here. Pick a wall-clock time on one side, read the matching wall-clock on the other from the table, and write both into the calendar invite, never just the difference. If the meeting falls in the week of a DST changeover and one of these zones shifts, the absolute clock will drift by an hour from what the recipient expects. The table is computed for today's date, so for a future meeting open the converter linked above and pick the exact date.
One last note for asynchronous teams: business-hour overlap is the wrong metric for handoff workflows. If you operate on a follow-the-sun model, you actually want zero overlap, with one team logging off as the other starts. GMT and KST differ by 9 hours, which is close to an ideal handoff window.
GMTvsUTC
Greenwich Mean Time · Coordinated Universal Time
Compare →ESTvsGMT
Eastern Standard Time · Greenwich Mean Time
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Eastern Daylight Time · Greenwich Mean Time
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Central Standard Time · Greenwich Mean Time
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Greenwich Mean Time · Pacific Standard Time
Compare →GMTvsMST
Greenwich Mean Time · Mountain Standard Time
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Greenwich Mean Time · India Standard Time
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Greenwich Mean Time · Japan Standard Time
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