Convert ACST to JST
JST is 30 minutes behind ACST. ACST is UTC+9:30 and JST is UTC+9.
Right now: ACST · JST
Best time to schedule a meeting
Standard 9–5 working hours overlap for 7 hours: 10:00 AM–5:00 PM ACST (9:00 AM–4:00 PM JST). Schedule meetings inside that window.
| ACST | JST | Suitable? |
|---|---|---|
| 9:00 AM | 8:30 AM | outside 9–5 |
| 10:00 AM | 9:30 AM | working hours |
| 11:00 AM | 10:30 AM | working hours |
| 12:00 PM | 11:30 AM | working hours |
| 1:00 PM | 12:30 PM | working hours |
| 2:00 PM | 1:30 PM | working hours |
| 3:00 PM | 2:30 PM | working hours |
| 4:00 PM | 3:30 PM | working hours |
| 5:00 PM | 4:30 PM | working hours |
ACST to JST conversion table
| ACST | JST |
|---|---|
| 12:00 AM | 11:30 PM (previous day) |
| 1:00 AM | 12:30 AM |
| 2:00 AM | 1:30 AM |
| 3:00 AM | 2:30 AM |
| 4:00 AM | 3:30 AM |
| 5:00 AM | 4:30 AM |
| 6:00 AM | 5:30 AM |
| 7:00 AM | 6:30 AM |
| 8:00 AM | 7:30 AM |
| 9:00 AM | 8:30 AM |
| 10:00 AM | 9:30 AM |
| 11:00 AM | 10:30 AM |
| 12:00 PM | 11:30 AM |
| 1:00 PM | 12:30 PM |
| 2:00 PM | 1:30 PM |
| 3:00 PM | 2:30 PM |
| 4:00 PM | 3:30 PM |
| 5:00 PM | 4:30 PM |
| 6:00 PM | 5:30 PM |
| 7:00 PM | 6:30 PM |
| 8:00 PM | 7:30 PM |
| 9:00 PM | 8:30 PM |
| 10:00 PM | 9:30 PM |
| 11:00 PM | 10:30 PM |
About ACST
Australian Central Standard Time (ACST) is UTC+9:30. It is used in Adelaide and Darwin in winter.
Australian Central Standard Time is UTC+9:30, half an hour behind the eastern states rather than a whole hour, which surprises people every time. South Australia moves to daylight saving in October and the Northern Territory does not, so Adelaide and Darwin share this offset for half the year and are an hour apart for the other half.
About JST
Japan Standard Time (JST) is UTC+9. It is used in all of Japan, with no daylight saving.
Japan Standard Time is UTC+9 for the whole country and has had no daylight saving since 1951, when the occupation-era experiment was abandoned. Proposals to reintroduce it, most recently before the 2020 Olympics, have failed each time. The offset is shared with South Korea, so Tokyo and Seoul never differ by even a minute.
Does this gap change with the seasons?
Neither ACST nor JST shifts with the seasons, so this 0.5-hour difference holds all year. That is unusual enough to be worth relying on: most cross-continental gaps move twice a year.
This is the reason scheduling systems store an IANA zone such as Region/City rather than an offset or an abbreviation: the zone knows its own rules and the offset does not.
Frequently asked questions
What time is 9:00 AM ACST in JST?
9:00 AM ACST is 8:30 AM JST.
Is JST ahead of ACST?
JST is 30 minutes behind ACST.
Which time zone does this use?
ACST is UTC+9:30 and JST is UTC+9. Both abbreviations denote a single fixed offset, so this conversion never shifts with daylight saving — what changes is which abbreviation a place is using at the time.