HST to JST Time Converter
JST is 19 hours ahead of HST. HST is UTC-10:00, and JST is UTC+9:00.
Best Time to Call Between HST and JST
Both zones are inside normal business hours between 2:00 PM and 5:00 PM HST — that's 9:00 AM to 12:00 PM JST. That's a 3-hour window.
both at work HST only JST only neither — hours along the strip are HST.
Common Times Converted
HST on the left, JST on the right.
HST to JST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| HST | JST | Working hours |
|---|---|---|
| 12:00 AM | 7:00 PM | — |
| 1:00 AM | 8:00 PM | — |
| 2:00 AM | 9:00 PM | — |
| 3:00 AM | 10:00 PM | — |
| 4:00 AM | 11:00 PM | — |
| 5:00 AM | 12:00 AM next day | — |
| 6:00 AM | 1:00 AM next day | — |
| 7:00 AM | 2:00 AM next day | — |
| 8:00 AM | 3:00 AM next day | — |
| 9:00 AM | 4:00 AM next day | HST only |
| 10:00 AM | 5:00 AM next day | HST only |
| 11:00 AM | 6:00 AM next day | HST only |
| 12:00 PM | 7:00 AM next day | HST only |
| 1:00 PM | 8:00 AM next day | HST only |
| 2:00 PM | 9:00 AM next day | Both zones |
| 3:00 PM | 10:00 AM next day | Both zones |
| 4:00 PM | 11:00 AM next day | Both zones |
| 5:00 PM | 12:00 PM next day | JST only |
| 6:00 PM | 1:00 PM next day | JST only |
| 7:00 PM | 2:00 PM next day | JST only |
| 8:00 PM | 3:00 PM next day | JST only |
| 9:00 PM | 4:00 PM next day | JST only |
| 10:00 PM | 5:00 PM next day | — |
| 11:00 PM | 6:00 PM next day | — |
What HST and JST Actually Are
HST — Hawaii Standard Time
Honolulu and the rest of Hawaii. Standing at UTC-10:00 as written, and the region does not change its clocks, so that offset holds all year. Hawaii does not observe daylight saving, so this offset holds all year.
Hawaii dropped daylight saving in 1967 and never resumed it. Being close to the equator, its daylight barely varies across the year, so there is little to gain.
JST — Japan Standard Time
Tokyo, Osaka, Yokohama, Nagoya, Sapporo. Standing at UTC+9:00 as written, and the region does not change its clocks, so that offset holds all year. Japan does not observe daylight saving, so this offset is fixed year-round.
Japan abolished daylight saving in 1952 and has resisted every attempt to reintroduce it, including a proposal around the 2020 Olympics.
What This Means in Practice
The date changes mid-working-day
For 8 of the eight hours in a normal HST working day, the equivalent JST time falls on a different calendar date. Anything scheduled in that stretch needs the date checked as well as the time, or a Tuesday call quietly becomes a Wednesday one at the other end.
A gap you can rely on
Neither region changes its clocks, so this difference holds every day of the year. A recurring meeting booked once stays correct — worth knowing, because most cross-border pairs cannot say that.
Nearly opposite sides of the clock
At 19 hours apart, one side's morning is the other side's night. Handing work over at the end of a shift usually beats trying to get both parties in the same call.
Major Cities in Each Zone
Cities on HST
Cities on JST
Frequently Asked Questions
What is the time difference between HST and JST?
JST is 19 hours ahead of HST.
What is 9:00 AM HST in JST?
9:00 AM HST is 4:00 AM the next day JST.
What are the best hours to schedule a call between HST and JST?
Between 2:00 PM and 5:00 PM HST, which is 9:00 AM to 12:00 PM JST. Both sides are inside normal business hours through that window.
Does the difference between HST and JST change during the year?
No. Neither region changes its clocks, so this gap is fixed all year round.
Does HST always mean Hawaii Standard Time?
Hawaii does not observe daylight saving, so this offset holds all year.
Does JST always mean Japan Standard Time?
Japan does not observe daylight saving, so this offset is fixed year-round.