ACST to KST
-0h 30mACST
ACSTSOURCEKST
KSTGreen rows indicate typical business hours (9 AM - 5 PM)
ACST and KST on the World Map
The map below highlights the ACST (Australian Central Standard Time) and KST (Korea Standard Time) timezone regions across the globe.
ACST – Australian Central Standard Time
UTC+09:30Australian Central Standard Time (ACST, UTC+09:30) covers South Australia and the Northern Territory, on a half-hour offset.
- •ACST uses a half-hour offset: UTC+09:30.
- •South Australia moves to ACDT (UTC+10:30) in summer; the Northern Territory does not.
- •Adelaide and Darwin are 30 minutes apart during daylight saving, level in winter.
- •Adelaide is one of the few major cities on a 30-minute offset.
KST – Korea Standard Time
UTC+09:00Korea Standard Time (KST) is the time zone for South Korea, 9 hours ahead of UTC.
- •South Korea does not observe daylight saving time.
- •Seoul is home to Samsung, LG, and Hyundai headquarters.
- •KST is the same offset as JST (UTC+09:00).
Everything You Need to Know About ACST and KST Time
ACST runs on Australian Central Standard Time (ACST) at UTC+09:30. KST runs on Korea Standard Time (KST) at UTC+09:00. That puts ACST 30 minutes behind KST — a difference of -0h 30m at the current offsets.
In practice, when it is 9:00 AM in ACST it is 8:30 AM in KST. Midnight in ACST is 11:30 PM in KST. Neither zone observes daylight saving time, so the offset between them stays constant all year.
ACST to KST time conversion table
| ACST (ACST) | KST (KST) | Day |
|---|---|---|
| 12:00 AM | 11:30 PM | previous day |
| 6:00 AM | 5:30 AM | same day |
| 7:00 AM | 6:30 AM | same day |
| 8:00 AM | 7:30 AM | same day |
| 9:00 AM | 8:30 AM | same day |
| 12:00 PM | 11:30 AM | same day |
| 3:00 PM | 2:30 PM | same day |
| 5:00 PM | 4:30 PM | same day |
| 6:00 PM | 5:30 PM | same day |
| 9:00 PM | 8:30 PM | same day |
Why people convert ACST to KST time
- Scheduling a call from ACST to KST: a 10:00 AM start in ACST lands at 9:30 AM in KST, so you can confirm the slot without doing the arithmetic yourself.
- Finding shared working hours: both ACST and KST are inside the 9-to-5 working day between 9:30 AM and 5:00 PM ACST time (9:00 AM–4:30 PM KST). That is roughly 7 hours 30 minutes of usable overlap.
- Coordinating a ACST-based team with KST contacts: quoting times in the other side's local clock — not your own — removes the single biggest source of missed meetings.
- Always state the zone abbreviation, not just the hour. "3:00 PM ACST" is unambiguous; "3 PM" across a -0h 30m gap is not.
- Block 9:30 AM–5:00 PM ACST as the recurring meeting window if you work primarily from ACST and need KST colleagues present.
About ACST (Australian Central Standard Time)
Australian Central Standard Time (ACST) is the half-hour offset of UTC+09:30 used across South Australia and the Northern Territory, taking in Adelaide and Darwin. South Australia moves to Australian Central Daylight Time (ACDT, UTC+10:30) from the first Sunday in October to the first Sunday in April, but the Northern Territory does not observe daylight saving — so Adelaide and Darwin sit 30 minutes apart in summer and level with each other in winter. The half-hour offset means Adelaide is 30 minutes behind Sydney in winter and level with it during daylight saving, which regularly catches out travellers and meeting planners.
About KST (Korea Standard Time)
Korea Standard Time (KST) is the time zone used in South Korea. It shares the same UTC offset as Japan Standard Time but is a distinct time zone. South Korea does not observe daylight saving time. Seoul, the capital, is a major global tech and business hub.
Best time to call between ACST and KST
Both ACST and KST sit inside the 9 AM – 5 PM working day between 9:30 AM–5:00 PM ACST, which is 9:00 AM–4:30 PM KST. That gives roughly 7 hours and 30 minutes of shared time — the safest window for a live call or meeting.
Business hours overlap
ACST and KST share 7 hours of working-hours overlap (9:30 AM–5:00 PM ACST), so scheduling a live meeting is straightforward.
ACST is 30 minutes behind KST (ACST UTC+09:30 → KST UTC+09:00). The shared working window is 9:30 AM–5:00 PM ACST. Remember to re-check around daylight-saving transitions.
🕐 Daylight Saving Time Info
ACST
❄ Currently in Standard Time
Standard: UTC+09:30 · DST: UTC+10:30
Clocks spring forward on Sat, Oct 3, 2026
KST
Does not observe DST
Learn More About Time
Dive deeper into the fascinating world of timekeeping, time zones, and how they shape our global society:
Frequently Asked Questions
What is the time difference between ACST and KST?
ACST (ACST, UTC+09:30) is 30 minutes behind KST (KST, UTC+09:00). The gap is currently -0h 30m.
How do I convert ACST time to KST time?
Add -0h 30m to ACST local time. For example, 9:00 AM in ACST is 8:30 AM in KST.
What time is it in KST right now?
KST uses KST at UTC+09:00. Use the live converter at the top of this page — it updates in real time and already accounts for the -0h 30m offset from ACST.
What is the best time to call KST from ACST?
Call between 9:30 AM and 5:00 PM ACST — that maps to 9:00 AM–4:30 PM KST and keeps both parties inside the working day.
Which is behind, ACST or KST?
ACST is 30 minutes behind KST. When it is 12:00 PM in ACST it is 11:30 AM in KST.
Does daylight saving time affect the ACST–KST difference?
Neither zone observes daylight saving time, so the -0h 30m offset between ACST and KST is fixed all year.
Which other cities share ACST's time zone?
ACST also covers Adelaide, Darwin, Alice Springs, Mount Gambier.
Which countries use ACST, ACST's zone?
ACST is used in Australia (South Australia, Northern Territory).
Is there a day difference between ACST and KST?
Not normally. The -0h 30m gap only pushes the date over the previous day.
What is the time difference between ACST and KST?
KST is -0h 30m from ACST.
What timezone is ACST in?
ACST operates on its local timezone.
What timezone is KST in?
KST operates on its local timezone.
Which countries use ACST (Australian Central Standard Time)?
ACST is used in Australia (South Australia, Northern Territory).
Does ACST observe daylight saving time?
Yes, ACST switches to ACDT during summer months.
What are some interesting facts about ACST?
ACST uses a half-hour offset: UTC+09:30. South Australia moves to ACDT (UTC+10:30) in summer; the Northern Territory does not.
Which cities are in the KST timezone?
Major cities in the KST timezone include Seoul, Busan, Incheon, Daegu, Daejeon, Pyongyang.
What is the UTC offset for KST?
Korea Standard Time (KST) is at UTC+09:00.
What should I know about the KST timezone?
South Korea does not observe daylight saving time. Seoul is home to Samsung, LG, and Hyundai headquarters.
When is it midnight in ACST, what time is it in KST?
When it is 12:00 AM (midnight) in ACST (ACST), it is -0h 30m later in KST (KST).
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See every conversion from ACST →·See every conversion from KST →