ACST to CST time conversion
CST is 15 hours 30 minutes behind ACST.
ACST is always UTC+9:30. Right now most places that use ACST are on ACDT (UTC+10:30): CST is 16 hours 30 minutes behind ACDT.
CST is always UTC-6. Right now most places that use CST are on CDT (UTC-5): CDT is 14 hours 30 minutes behind ACST.
Time difference with your location
ACST is 9 hours 30 minutes ahead of UTC. Compare with your local time →
Choose a date and time
Choose the local time in ACST to convert it to CST on that date.
Skipped clock-change times are unavailable; a repeated time uses its first occurrence.
24-hour conversion chart · ACST → CST
This table converts each hour in ACST to CST on 2026-10-22.
- Working hours
- Outside working hours
- Night hours
| ACST | CST | Shared working hours |
|---|---|---|
| 00:0012:00 AM | 08:308:30 AM -1 day | |
| 01:001:00 AM | 09:309:30 AM -1 day | |
| 02:002:00 AM | 10:3010:30 AM -1 day | |
| 03:003:00 AM | 11:3011:30 AM -1 day | |
| 04:004:00 AM | 12:3012:30 PM -1 day | |
| 05:005:00 AM | 13:301:30 PM -1 day | |
| 06:006:00 AM | 14:302:30 PM -1 day | |
| 07:007:00 AM | 15:303:30 PM -1 day | |
| 08:008:00 AM | 16:304:30 PM -1 day | ✓ |
| 09:009:00 AM | 17:305:30 PM -1 day | ✓ |
| 10:0010:00 AM | 18:306:30 PM -1 day | |
| 11:0011:00 AM | 19:307:30 PM -1 day | |
| 12:0012:00 PM | 20:308:30 PM -1 day | |
| 13:001:00 PM | 21:309:30 PM -1 day | |
| 14:002:00 PM | 22:3010:30 PM -1 day | |
| 15:003:00 PM | 23:3011:30 PM -1 day | |
| 16:004:00 PM | 00:3012:30 AM | |
| 17:005:00 PM | 01:301:30 AM | |
| 18:006:00 PM | 02:302:30 AM | |
| 19:007:00 PM | 03:303:30 AM | |
| 20:008:00 PM | 04:304:30 AM | |
| 21:009:00 PM | 05:305:30 AM | |
| 22:0010:00 PM | 06:306:30 AM | |
| 23:0011:00 PM | 07:307:30 AM |
Quick conversion examples
These examples use ACST (UTC+9:30) and CST (UTC-6); choosing a date applies the local clock changes.
Conversion formula: CST = ACST − 15h30 · ACDT − 16h30 · CDT = ACDT − 15h30 · CDT = ACST − 14h30.
| ACST | CST |
|---|---|
| 6:00 AM ACST | = 2:30 PM CST (-1 day) |
| 7:00 AM ACST | = 3:30 PM CST (-1 day) |
| 8:00 AM ACST | = 4:30 PM CST (-1 day) |
| 9:00 AM ACST | = 5:30 PM CST (-1 day) |
| 10:00 AM ACST | = 6:30 PM CST (-1 day) |
| 12:00 PM ACST | = 8:30 PM CST (-1 day) |
| 3:00 PM ACST | = 11:30 PM CST (-1 day) |
| 5:00 PM ACST | = 1:30 AM CST |
| 6:00 PM ACST | = 2:30 AM CST |
| 8:00 PM ACST | = 4:30 AM CST |
Overlapping meeting hours
The 08:00–18:00 working day in ACST and CST overlaps for 1 hour 30 minutes on 2026-10-22.
- Shared working hours
- 08:00–09:30 ACST · 16:30–18:00 CST
Clock changes on both sides, 2026–2028
ACST and CST have the following local clock changes in 2026–2028; all times in the table are local to that side.
| Year | ACST | CST |
|---|---|---|
| 2026 | · 03:00 → 02:00 · 02:00 → 03:00 | · 02:00 → 03:00 · 02:00 → 01:00 |
| 2027 | · 03:00 → 02:00 · 02:00 → 03:00 | · 02:00 → 03:00 · 02:00 → 01:00 |
| 2028 | · 03:00 → 02:00 · 02:00 → 03:00 | · 02:00 → 03:00 · 02:00 → 01:00 |
At the start of 2026, CST is 16 hours 30 minutes behind ACDT. The difference changes during the following periods.
- From 2026-03-08 18:30 ACDT until 2026-04-05 02:00 ACST, CDT is 15 hours 30 minutes behind ACDT.
- From 2026-04-05 02:00 ACST until 2026-10-04 03:00 ACDT, CDT is 14 hours 30 minutes behind ACST.
- From 2026-10-04 03:00 ACDT until 2026-11-01 17:30 ACDT, CDT is 15 hours 30 minutes behind ACDT.
- From 2027-03-14 18:30 ACDT until 2027-04-04 02:00 ACST, CDT is 15 hours 30 minutes behind ACDT.
- From 2027-04-04 02:00 ACST until 2027-10-03 03:00 ACDT, CDT is 14 hours 30 minutes behind ACST.
- From 2027-10-03 03:00 ACDT until 2027-11-07 17:30 ACDT, CDT is 15 hours 30 minutes behind ACDT.
- From 2028-03-12 18:30 ACDT until 2028-04-02 02:00 ACST, CDT is 15 hours 30 minutes behind ACDT.
- From 2028-04-02 02:00 ACST until 2028-10-01 03:00 ACDT, CDT is 14 hours 30 minutes behind ACST.
- From 2028-10-01 03:00 ACDT until 2028-11-05 17:30 ACDT, CDT is 15 hours 30 minutes behind ACDT.
Frequently asked questions
What time is 9 AM ACST in CST?
9:00 AM ACST = 5:30 PM CST (-1 day), using UTC+9:30 and UTC-6. Choose a date above for the seasonal local time.
Does the time difference between ACST and CST change during the year?
Yes. During 2026–2028: CST is 16 hours 30 minutes behind ACST; CST is 15 hours 30 minutes behind ACST; CST is 14 hours 30 minutes behind ACST. The clock-change table gives the dates for both sides.
How do I tell whether it is day or night in CST?
Read the CST 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 ACST and CST?
The shared 08:00–18:00 working window is 08:00–09:30 ACST / 16:30–18:00 CST, a total of 1 hour 30 minutes.
What is the time difference between ACST and CST now?
Right now, CST is 15 hours 30 minutes behind ACST. Conversion formula: CST = ACST − 15h30 · ACDT − 16h30 · CDT = ACDT − 15h30 · CDT = ACST − 14h30.