JST to HST Converter
Understanding JST and HST Time Zones
Japan Standard Time (JST)
Japan Standard Time is observed in undefined and uses the offset UTC+9. Major cities in this time zone include Tokyo, Osaka, Yokohama. This time zone serves a significant global region with important economic and cultural hubs.
Hawaii Standard Time (HST)
Hawaii Standard Time operates at UTC-10, covering undefined. Key cities include Honolulu, Maui. The 19-hour backward offset from JST means that when professionals in Tokyo start their workday at 9:00 AM, it is already 2:00 PM in Honolulu.
JST is also commonly referred to as Japan time, Tokyo time, Japanese time. HST is also known as Hawaii Time, Honolulu time, Hawaiian time. So if you are searching for Japan time to Hawaii Time, this is the same conversion as JST to HST.
Complete JST to HST Conversion Table
The table below shows every two-hour increment converted from Japan Standard Time to Hawaii Standard Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.
| JST (Japan Standard Time) | HST (Hawaii Standard Time) |
|---|---|
| 12:00 AM (00:00) | 5:00 AM (05:00) (previous day) |
| 2:00 AM (02:00) | 7:00 AM (07:00) (previous day) |
| 4:00 AM (04:00) | 9:00 AM (09:00) (previous day) |
| 6:00 AM (06:00) | 11:00 AM (11:00) (previous day) |
| 8:00 AM (08:00) | 1:00 PM (13:00) (previous day) |
| 10:00 AM (10:00) | 3:00 PM (15:00) (previous day) |
| 12:00 PM (12:00) | 5:00 PM (17:00) (previous day) |
| 2:00 PM (14:00) | 7:00 PM (19:00) (previous day) |
| 4:00 PM (16:00) | 9:00 PM (21:00) (previous day) |
| 6:00 PM (18:00) | 11:00 PM (23:00) (previous day) |
| 8:00 PM (20:00) | 1:00 AM (01:00) |
| 10:00 PM (22:00) | 3:00 AM (03:00) |
Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.
Scheduling Between JST and HST
For business scheduling, the optimal overlap window between JST and HST falls roughly between 9:00 AM and 12:00 PM JST. This ensures both Tokyo and Honolulu teams are within standard working hours.
The large 19-hour gap between JST and HST means that finding overlapping working hours requires compromise from at least one side. Consider adopting asynchronous workflows — recorded video updates, shared documents, and time-zone-aware project management tools — to supplement the limited real-time overlap.
Travel Between Tokyo and Honolulu
Travelers flying from Tokyo to Honolulu should adjust their sleep schedule 19 days before departure at a rate of one hour per day. For this significant time difference, gradual adjustment reduces jet lag dramatically.
Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 19-hour shift between JST and HST, plan for roughly one week of gradual adjustment for optimal performance.
Daylight Saving Time Considerations
During standard time months (November through March in the US), this offset is fixed. However, if either zone observes daylight saving time, the difference may temporarily shift by one hour during transition weeks in spring and autumn.
For the JST to HST conversion specifically: JST (UTC+9) and HST (UTC-10) neither observes DST, so the 19-hour offset remains constant throughout the year. This makes scheduling reliable and predictable.
Related Time Zone Conversions
References & Resources
Frequently Asked Questions
JST (Japan Standard Time) is 19 hours ahead of HST (Hawaii Standard Time). JST is UTC+9 and HST is UTC-10.
When it is 12:00 PM (noon) in JST, it is 5:00 PM (previous day) in HST.
The best overlap for business hours is approximately 2:00 PM to 10:00 PM HST, which corresponds to 9:00 AM to 5:00 PM in JST. Given the large gap, consider alternating between early and late meeting times.
During standard time months (November through March in the US), this offset is fixed. However, if either zone observes daylight saving time, the difference may temporarily shift by one hour during transition weeks in spring and autumn.