KST
Korea Standard Time
GMT +9
12am
3am
6am
9am
12pm
3pm
6pm
9pm
HST
Hawaii Standard Time
GMT -10
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

KST is 19 hours ahead of HST. KST uses GMT +9, and HST uses GMT -10 for this comparison.

For example, 9:00 pm KST is 2:00 am HST. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 9am-12pm KST, which is 2pm-5pm HST (previous day).

Compare KST time with HST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Korea Standard Time is 19 hours ahead of Hawaii Standard Time
9:00 pm21:00 in KST is 2:00 am02:00 in HST

KST to HST call time
Best time for a conference call or a meeting is between 9am-12pm in KST which corresponds to 2pm-5pm in HST (previous day)

9:00 pm21:00 Korea Standard Time (KST). Offset UTC +9:00 hours
2:00 am02:00 Hawaii Standard Time (HST). Offset UTC -10:00 hours

9:00 pm21:00 KST / 2:00 am02:00 HST

KSTHST
12am (midnight)5am
1am6am
2am7am
3am8am
4am9am
5am10am
6am11am
7am12pm (noon)
8am1pm
9am2pm
10am3pm
11am4pm
12pm (noon)5pm
1pm6pm
2pm7pm
3pm8pm
4pm9pm
5pm10pm
6pm11pm
7pm12am (midnight)
8pm1am
9pm2am
10pm3am
11pm4am
00:0005:00
01:0006:00
02:0007:00
03:0008:00
04:0009:00
05:0010:00
06:0011:00
07:0012:00
08:0013:00
09:0014:00
10:0015:00
11:0016:00
12:0017:00
13:0018:00
14:0019:00
15:0020:00
16:0021:00
17:0022:00
18:0023:00
19:0000:00
20:0001:00
21:0002:00
22:0003:00
23:0004:00

Korea Standard Time

Offset: KST is 9 hours ahead Greenwich Mean Time (GMT) and is used in Asia

Countries using this time zone: Korea (North), Korea (South)

Principal Cities: The largest city in the KST time zone is Seoul in South Korea, with about 10.349 million people. Other major cities in this time zone include Busan, Pyongyang, Incheon, Daegu.

Daylight Saving: Clocks in Korea Standard Time (KST) do not change for daylight saving time, so KST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter.

KST Time Zone Geo Map
KST timezone map

KST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +09 - basic short
  • +0900 - basic
  • +09:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0900 - sign character (+) followed by a four digit time providing hours (09) and minutes (00) of the offset. Indicates an offset of nine hours to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • India - Military abbreviation for KST
  • I - short form of 'India'
IANA/Olson: Reflects KST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Asia/Pyongyang
  • Asia/Seoul
  • ROK
KST Abbreviation: Several time zones share KST abbreviation and it could refer to these time zones
  • Korea Standard Time - UTC +9
  • Pyongyang Time - UTC +8:30
Time zones with the GMT +9 offset:
  • AWDT - Australian Western Daylight Time
  • CHOST - Choibalsan Summer Time
  • I - India Time Zone
  • IRKST - Irkutsk Summer Time
  • JST - Japan Standard Time
  • KST - Korea Standard Time
  • PWT - Palau Time
  • TLT - East Timor Time
  • ULAST - Ulaanbaatar Summer Time
  • WIT - Eastern Indonesian Time
  • YAKT - Yakutsk Time

Hawaii Standard Time

Offset: HST is 10 hours behind Greenwich Mean Time (GMT) and is used in Pacific

Countries using this time zone: United States

Principal Cities: The largest city in the HST time zone is Honolulu in the United States, with about 371,657 people. Other major cities in this time zone include Pearl City, Hilo, Kailua, Waipahu.

Daylight Saving: Clocks in Hawaii Standard Time (HST) do not change for daylight saving time, so HST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter.

HST Time Zone Geo Map
HST timezone map

HST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -10 - basic short
  • -1000 - basic
  • -10:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -1000 - sign character (-) followed by a four digit time providing hours (10) and minutes (00) of the offset. Indicates an offset of ten hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Whiskey - Military abbreviation for HST
  • W - short form of 'Whiskey'
IANA/Olson: Reflects HST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Adak
  • America/Atka
  • HST
  • Pacific/Honolulu
  • Pacific/Johnston
  • US/Aleutian
  • US/Hawaii
Time zones with the GMT -10 offset:
  • HAST - Hawaii-Aleutian Standard Time
  • CKT - Cook Island Time
  • HST - Hawaii Standard Time
  • TAHT - Tahiti Time
  • W - Whiskey Time Zone