KST to HST Converter
Convert time between Korea Standard Time (KST) and Hawaii Standard Time (HST)
Korea Standard Time (KST)
Hawaii Standard Time (HST)
Time Difference
Hawaii Standard Time (HST) is 0 hours ahead of Korea Standard Time (KST)
Select Date
Select Time
Quick Reference
| KST | HST |
|---|---|
| 11:00 | 16:00 |
| 13:00 | 18:00 |
| 15:00 | 20:00 |
| 17:00 | 22:00 |
| 19:00 | 00:00 |
| 21:00 | 02:00 |
| 23:00 | 04:00 |
| 01:00 | 06:00 |
| 03:00 | 08:00 |
| 05:00 | 10:00 |
| 07:00 | 12:00 |
| 09:00 | 14:00 |
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 HST Time Conversion
Converting time from Korea Standard Time (KST) to Hawaii Standard Time (HST) bridges Asia and the central Pacific. KST is UTC+9, while HST is UTC-10, making KST 19 hours ahead of HST. Neither region observes daylight saving time, so this gap is rock-steady year-round.
With this near-day offset, the Korean date is typically a calendar day ahead of the Hawaiian date. Whether you are coordinating with Honolulu-based teams on tourism, education, or media projects, our IANA-based converter gives reliable results every day of the year.
Common Use Cases for KST to HST Conversion
Business & Work
- Scheduling cross-Pacific calls between Korean teams and Honolulu offices
- Coordinating tourism, hospitality, or media operations between South Korea and Hawaii
- Planning project handoffs that follow the sun between Asia and the Pacific
Personal & Travel
- Keeping in touch with family or friends living in Hawaii
- Planning travel from South Korea to Honolulu or other Hawaiian cities
- Scheduling virtual events that span Asia and Hawaii
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
Hawaii Standard Time (HST)
- UTC Offset: UTC-10 (no DST observed)
- IANA Timezone: Pacific/Honolulu
- Daylight Saving: Hawaii does not observe daylight saving time
- Major Cities: Honolulu, Hilo, Kailua, Pearl City, Kahului
- Coverage: The Hawaiian Islands
Quick Reference: KST to HST
Remember: HST is always 19 hours behind KST. Neither region observes daylight saving time.
Frequently Asked Questions
What is the time difference between KST and HST?
Korea Standard Time (KST) is UTC+9, while Hawaii Standard Time (HST) is UTC-10. KST is 19 hours ahead of HST, so when it is 12:00 PM Monday in Seoul, it is 5:00 PM Sunday in Honolulu.
Does the KST to HST time difference change throughout the year?
No. Neither South Korea nor Hawaii observes daylight saving time. KST stays at UTC+9 and HST stays at UTC-10 every day of the year, so the 19-hour gap is constant.
Is the date always different between Korea and Hawaii?
Almost always. With KST 19 hours ahead of HST, the Korean date is typically a calendar day ahead of the Hawaiian date.
What are the best times to schedule KST to HST business calls?
Live overlap is narrow. A workable bridge is morning Korea (8–10 AM KST), which is 1–3 PM HST the previous day — afternoon for the Hawaiian side, start of day for the Korean side. Asynchronous handoffs are often more practical for long-running collaboration.
Which regions and cities use HST?
HST (UTC-10) is used exclusively by the Hawaiian Islands. Major cities include Honolulu, Hilo, Kailua, Pearl City, and Kahului. Hawaii does not observe daylight saving time.
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
- • HST is always 19 hours behind KST — almost a full day, so the Hawaiian date is usually one calendar day before Korea.
- • Neither region observes DST, so this conversion is constant year-round — no surprises in spring or autumn.
- • For live calls, morning Korea (8–10 AM KST) lines up with afternoon Hawaii the previous day (1–3 PM HST).
- • Korean tourism and education firms often have ties to Hawaii — the stable offset makes long-running coordination predictable.
- • Direct flights between Seoul and Honolulu take roughly 9 hours and cross the date line — expect to gain or lose a calendar day.
- • For recurring meetings, fix one local time (Korean or Hawaiian) and stick to it — there are no DST shifts to plan around.