What is the time difference between HST and KST?

Korea Standard Time (KST) is 19 hours ahead of Hawaii Standard Time (HST). HST uses a UTC offset of UTC-10, while KST uses UTC+9. For example, when it's 9:00 AM in HST, it's 4:00 AM in KST. This difference remains constant year-round since neither timezone observes daylight saving time. Use the conversion table above to see the exact time for each hour of the day.

How do I convert HST to KST?

To convert HST to KST, add 19 hours to the HST time. For example, 9:00 AM HST is 4:00 AM KST, and 5:00 PM HST is 12:00 PM KST. Since neither timezone observes DST, this conversion stays the same all year. You can also use the interactive converter above for quick, accurate results.

What time is it in KST when it's noon in HST?

When it's 12:00 PM (noon) in HST, it's 7:00 AM in KST. This is because KST is 19 hours ahead of HST. Similarly, when it's 6:00 PM in HST, it's 1:00 PM in KST. This relationship is constant throughout the year. The color-coded conversion table above shows every hour mapped between both timezones.

How many hours ahead is KST from HST?

KST is 19 hours ahead of HST. This means when it's 9:00 AM in HST, it's 4:00 AM in KST, and when it's midnight in HST, it's 7:00 PM in KST. This offset is constant throughout the year since neither timezone uses daylight saving time. The conversion table above provides a complete hour-by-hour mapping.

Is KST ahead or behind HST?

KST is ahead of HST by 19 hours. Clocks in KST show a later time than HST, meaning the day starts earlier in KST relative to HST. For example, when it's morning in HST, it's already afternoon or evening in KST. This difference stays the same year-round.

Does HST observe daylight saving time?

No, Hawaii Standard Time does not observe daylight saving time. The UTC offset of UTC-10 remains the same year-round, making time conversions from HST more predictable. Countries and regions in this timezone keep their clocks unchanged regardless of the season.

Does KST observe daylight saving time?

No, Korea Standard Time does not observe daylight saving time. The UTC offset of UTC+9 remains the same year-round, making time conversions to KST more predictable. Countries and regions in this timezone keep their clocks unchanged regardless of the season.

What is the best time to call from HST to KST?

The best time for a call between HST and KST is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in KST during their work day, call between 2:00 PM and 10:00 PM your HST time. Avoid calling too early or late, as the 19 hours difference means your evening could be their late night. Check the color-coded conversion table above — green hours indicate business hours in both zones, making it easy to find the ideal time.

Do HST and KST ever have the same time?

No, HST and KST are always 19 hours apart and never display the same clock time simultaneously. Neither timezone observes DST, so the difference is constant year-round with no seasonal variation. The 19 hours offset is determined by their fixed positions relative to the Prime Meridian (UTC). You can always rely on this consistent difference when planning across these timezones.

HST to KST Converter

Convert Hawaii Standard Time to Korea Standard Time. See the hour-by-hour conversion table below.

Timezone Details

Hawaii Standard Time

9:58 AM

Thursday, April 2, 2026

HST (UTC-10:00)

Korea Standard Time

4:58 AM

Friday, April 3, 2026

KST (UTC+09:00)

Difference: +19 hours

HST DST: No

KST DST: No

24-Hour Overview

HST — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

KST — 24-hour overview

7p7p

10p10p

11p

12a

1a1a

4a4a

7a7a

10a10a

11a

12p

1p1p

4p4p

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

KST to HST

Cities in These Timezones

HST Cities

Honolulu

KST Cities

Seoul Busan

More Tools

Compare HST & KST Plan a Meeting (HST & KST)See on Map

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

Hawaii Standard Time on Wikipedia Korea Standard Time on Wikipedia IANA Time Zone Database