KST to ACST time conversion
ACST is 30 minutes ahead of KST.
ACST is always UTC+9:30. Right now most places that use ACST are on ACDT (UTC+10:30): ACDT is 1 hour 30 minutes ahead of KST.
Time difference with your location
KST is 9 hours ahead of UTC. Compare with your local time →
Choose a date and time
Choose the local time in KST to convert it to ACST on that date.
Skipped clock-change times are unavailable; a repeated time uses its first occurrence.
24-hour conversion chart · KST → ACST
This table converts each hour in KST to ACST on 2026-10-21.
- Working hours
- Outside working hours
- Night hours
| KST | ACST | Shared working hours |
|---|---|---|
| 00:0012:00 AM | 00:3012:30 AM | |
| 01:001:00 AM | 01:301:30 AM | |
| 02:002:00 AM | 02:302:30 AM | |
| 03:003:00 AM | 03:303:30 AM | |
| 04:004:00 AM | 04:304:30 AM | |
| 05:005:00 AM | 05:305:30 AM | |
| 06:006:00 AM | 06:306:30 AM | |
| 07:007:00 AM | 07:307:30 AM | |
| 08:008:00 AM | 08:308:30 AM | ✓ |
| 09:009:00 AM | 09:309:30 AM | ✓ |
| 10:0010:00 AM | 10:3010:30 AM | ✓ |
| 11:0011:00 AM | 11:3011:30 AM | ✓ |
| 12:0012:00 PM | 12:3012:30 PM | ✓ |
| 13:001:00 PM | 13:301:30 PM | ✓ |
| 14:002:00 PM | 14:302:30 PM | ✓ |
| 15:003:00 PM | 15:303:30 PM | ✓ |
| 16:004:00 PM | 16:304:30 PM | ✓ |
| 17:005:00 PM | 17:305:30 PM | ✓ |
| 18:006:00 PM | 18:306:30 PM | |
| 19:007:00 PM | 19:307:30 PM | |
| 20:008:00 PM | 20:308:30 PM | |
| 21:009:00 PM | 21:309:30 PM | |
| 22:0010:00 PM | 22:3010:30 PM | |
| 23:0011:00 PM | 23:3011:30 PM |
Quick conversion examples
These examples use KST (UTC+9) and ACST (UTC+9:30); choosing a date applies the local clock changes.
Conversion formula: ACST = KST + 30m · ACDT = KST + 1h30.
| KST | ACST |
|---|---|
| 6:00 AM KST | = 6:30 AM ACST |
| 7:00 AM KST | = 7:30 AM ACST |
| 8:00 AM KST | = 8:30 AM ACST |
| 9:00 AM KST | = 9:30 AM ACST |
| 10:00 AM KST | = 10:30 AM ACST |
| 12:00 PM KST | = 12:30 PM ACST |
| 3:00 PM KST | = 3:30 PM ACST |
| 5:00 PM KST | = 5:30 PM ACST |
| 6:00 PM KST | = 6:30 PM ACST |
| 8:00 PM KST | = 8:30 PM ACST |
Overlapping meeting hours
The 08:00–18:00 working day in KST and ACST overlaps for 9 hours 30 minutes on 2026-10-21.
- Shared working hours
- 08:00–17:30 KST · 08:30–18:00 ACST
Clock changes on both sides, 2026–2028
KST and ACST have the following local clock changes in 2026–2028; all times in the table are local to that side.
| Year | KST | ACST |
|---|---|---|
| 2026 | No clock changes; UTC+9 all year. | · 03:00 → 02:00 · 02:00 → 03:00 |
| 2027 | No clock changes; UTC+9 all year. | · 03:00 → 02:00 · 02:00 → 03:00 |
| 2028 | No clock changes; UTC+9 all year. | · 03:00 → 02:00 · 02:00 → 03:00 |
At the start of 2026, ACDT is 1 hour 30 minutes ahead of KST. The difference changes during the following periods.
- From 2026-04-05 01:30 KST until 2026-10-04 01:30 KST, ACST is 30 minutes ahead of KST.
- From 2027-04-04 01:30 KST until 2027-10-03 01:30 KST, ACST is 30 minutes ahead of KST.
- From 2028-04-02 01:30 KST until 2028-10-01 01:30 KST, ACST is 30 minutes ahead of KST.
Frequently asked questions
What time is 9 AM KST in ACST?
9:00 AM KST = 9:30 AM ACST, using UTC+9 and UTC+9:30. Choose a date above for the seasonal local time.
Does the time difference between KST and ACST change during the year?
Yes. During 2026–2028: ACST is 30 minutes ahead of KST; ACST is 1 hour 30 minutes ahead of KST. The clock-change table gives the dates for both sides.
How do I tell whether it is day or night in ACST?
Read the ACST clock above: this guide counts 06:00–18:00 local time as daytime and the rest as nighttime, without using sunrise and sunset.
What is the best time to call between KST and ACST?
The shared 08:00–18:00 working window is 08:00–17:30 KST / 08:30–18:00 ACST, a total of 9 hours 30 minutes.
What is the time difference between KST and ACST now?
Right now, ACST is 30 minutes ahead of KST. Conversion formula: ACST = KST + 30m · ACDT = KST + 1h30.