Convert KST to ACST
ACST is 30 minutes ahead of KST. KST is UTC+9 and ACST is UTC+9:30.
Right now: KST · ACST
Best time to schedule a meeting
Standard 9–5 working hours overlap for 8 hours: 9:00 AM–5:00 PM KST (9:00 AM–5:00 PM ACST). Schedule meetings inside that window.
| KST | ACST | Suitable? |
|---|---|---|
| 9:00 AM | 9:30 AM | working hours |
| 10:00 AM | 10:30 AM | working hours |
| 11:00 AM | 11:30 AM | working hours |
| 12:00 PM | 12:30 PM | working hours |
| 1:00 PM | 1:30 PM | working hours |
| 2:00 PM | 2:30 PM | working hours |
| 3:00 PM | 3:30 PM | working hours |
| 4:00 PM | 4:30 PM | working hours |
| 5:00 PM | 5:30 PM | outside 9–5 |
KST to ACST conversion table
| KST | ACST |
|---|---|
| 12:00 AM | 12:30 AM |
| 1:00 AM | 1:30 AM |
| 2:00 AM | 2:30 AM |
| 3:00 AM | 3:30 AM |
| 4:00 AM | 4:30 AM |
| 5:00 AM | 5:30 AM |
| 6:00 AM | 6:30 AM |
| 7:00 AM | 7:30 AM |
| 8:00 AM | 8:30 AM |
| 9:00 AM | 9:30 AM |
| 10:00 AM | 10:30 AM |
| 11:00 AM | 11:30 AM |
| 12:00 PM | 12:30 PM |
| 1:00 PM | 1:30 PM |
| 2:00 PM | 2:30 PM |
| 3:00 PM | 3:30 PM |
| 4:00 PM | 4:30 PM |
| 5:00 PM | 5:30 PM |
| 6:00 PM | 6:30 PM |
| 7:00 PM | 7:30 PM |
| 8:00 PM | 8:30 PM |
| 9:00 PM | 9:30 PM |
| 10:00 PM | 10:30 PM |
| 11:00 PM | 11:30 PM |
About KST
Korea Standard Time (KST) is UTC+9. It is used in South Korea, with no daylight saving.
Korea Standard Time is UTC+9, the same as Japan, and South Korea has had no daylight saving since 1988 when it was used for the Seoul Olympics. The two Koreas briefly differed: the North moved to UTC+8:30 in 2015 and returned to UTC+9 in 2018, which is the only time in modern history the peninsula ran on two clocks.
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.
Does this gap change with the seasons?
Neither KST nor ACST 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 KST in ACST?
9:00 AM KST is 9:30 AM ACST.
Is ACST ahead of KST?
ACST is 30 minutes ahead of KST.
Which time zone does this use?
KST is UTC+9 and ACST is UTC+9:30. 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.