HST to KST Converter & Meeting Planner
Quick answer: 9:00 AM HST = 4:00 AM KST (fixed -10:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Hawaii-Aleutian Standard Time (HST) and Korea Standard Time (KST)? You need to account for the standard time difference. Korea Standard Time is normally 19 hours ahead of Hawaii-Aleutian Standard Time. Whether you are coordinating between teams in Honolulu and Hilo and Seoul and Busan, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM HST = 7:00 PM KST. The full 24-hour HST to KST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM HST = 10:00 AM KST (+1 day).
| HST Time | KST Time |
|---|---|
| 12:00 AM (00:00) | 7:00 PM (19:00) |
| 1:00 AM (01:00) | 8:00 PM (20:00) |
| 2:00 AM (02:00) | 9:00 PM (21:00) |
| 3:00 AM (03:00) | 10:00 PM (22:00) |
| 4:00 AM (04:00) | 11:00 PM (23:00) |
| 5:00 AM (05:00) | 12:00 AM (00:00)+1 day |
| 6:00 AM (06:00) | 1:00 AM (01:00)+1 day |
| 7:00 AM (07:00) | 2:00 AM (02:00)+1 day |
| 8:00 AM (08:00) | 3:00 AM (03:00)+1 day |
| 9:00 AM (09:00) | 4:00 AM (04:00)+1 day |
| 10:00 AM (10:00) | 5:00 AM (05:00)+1 day |
| 11:00 AM (11:00) | 6:00 AM (06:00)+1 day |
| 12:00 PM (12:00) | 7:00 AM (07:00)+1 day |
| 1:00 PM (13:00) | 8:00 AM (08:00)+1 day |
| 2:00 PM (14:00) | 9:00 AM (09:00)+1 day |
| 3:00 PM (15:00) | 10:00 AM (10:00)+1 day |
| 4:00 PM (16:00) | 11:00 AM (11:00)+1 day |
| 5:00 PM (17:00) | 12:00 PM (12:00)+1 day |
| 6:00 PM (18:00) | 1:00 PM (13:00)+1 day |
| 7:00 PM (19:00) | 2:00 PM (14:00)+1 day |
| 8:00 PM (20:00) | 3:00 PM (15:00)+1 day |
| 9:00 PM (21:00) | 4:00 PM (16:00)+1 day |
| 10:00 PM (22:00) | 5:00 PM (17:00)+1 day |
| 11:00 PM (23:00) | 6:00 PM (18:00)+1 day |
Best time to call Seoul from Honolulu
For most work calls, compare the normal business day in Honolulu (HST) with the business day in Seoul (KST). HST commonly covers Pacific Ocean, North America, while KST is mainly associated with East Asia.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
✅ The most practical overlap on 2026-07-05 is usually 2:00 PM - 5:00 PM HST, which corresponds to 9:00 AM - 12:00 PM KST. This window sits inside the typical HST workday (9:00 AM - 5:00 PM) and the KST workday (9:00 AM - 6:00 PM).
- DST Safety: HST or KST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Korea Exchange (KRX): 09:00-15:30 local time in Seoul.
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Frequently Asked Questions
What is the time difference between HST and KST?
During standard time, Korea Standard Time is 19 hours ahead of Hawaii-Aleutian Standard Time.
Does Hawaii observe Daylight Saving Time?
Hawaii does not observe Daylight Saving Time and has not done so since 1947, remaining fixed at UTC-10:00 year-round. At roughly 20° North latitude, Hawaii's daylight hours vary by only about 1.5 hours between the summer and winter solstices — far too little to justify the disruption of a seasonal clock change.
Why is it called Hawaii-Aleutian time?
The name combines two geographically distant US territories that share the same UTC-10:00 standard offset: the Hawaiian Islands in the central Pacific and the westernmost Aleutian Islands of Alaska, which extend past the 180° meridian into the Eastern Hemisphere. Despite sharing a base offset, they behave differently — Hawaii observes no DST, while the Aleutian communities such as Adak do advance to HDT (UTC-9) each summer.
Does South Korea observe Daylight Saving Time?
South Korea does not observe Daylight Saving Time and has not done so since 1988, when DST was discontinued following the Seoul Summer Olympics. KST remains fixed at UTC+9:00 every day of the year, meaning the offset between Seoul and any DST-observing country shifts by one hour twice annually when those countries change their clocks.
Are KST and JST the same?
Yes, Korea Standard Time (KST) and Japan Standard Time (JST) share the identical UTC+9:00 offset, and neither country observes Daylight Saving Time. Seoul and Tokyo run on exactly the same clock year-round, which directly supports the deep semiconductor, automotive, and consumer electronics supply chain integration between the two economies.