BST to ACST time conversion
ACST is 8 hours 30 minutes ahead of BST.
ACST is always UTC+9:30. Right now most places that use ACST are on ACDT (UTC+10:30): ACDT is 9 hours 30 minutes ahead of BST.
Time difference with your location
BST is 1 hour ahead of UTC. Compare with your local time →
Choose a date and time
Choose the local time in BST 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 · BST → ACST
This table converts each hour in BST to ACST on 2026-10-21.
- Working hours
- Outside working hours
- Night hours
| BST | ACST | Shared working hours |
|---|---|---|
| 00:0012:00 AM | 08:308:30 AM | |
| 01:001:00 AM | 09:309:30 AM | |
| 02:002:00 AM | 10:3010:30 AM | |
| 03:003:00 AM | 11:3011:30 AM | |
| 04:004:00 AM | 12:3012:30 PM | |
| 05:005:00 AM | 13:301:30 PM | |
| 06:006:00 AM | 14:302:30 PM | |
| 07:007:00 AM | 15:303:30 PM | |
| 08:008:00 AM | 16:304:30 PM | ✓ |
| 09:009:00 AM | 17:305:30 PM | ✓ |
| 10:0010:00 AM | 18:306:30 PM | |
| 11:0011:00 AM | 19:307:30 PM | |
| 12:0012:00 PM | 20:308:30 PM | |
| 13:001:00 PM | 21:309:30 PM | |
| 14:002:00 PM | 22:3010:30 PM | |
| 15:003:00 PM | 23:3011:30 PM | |
| 16:004:00 PM | 00:3012:30 AM +1 day | |
| 17:005:00 PM | 01:301:30 AM +1 day | |
| 18:006:00 PM | 02:302:30 AM +1 day | |
| 19:007:00 PM | 03:303:30 AM +1 day | |
| 20:008:00 PM | 04:304:30 AM +1 day | |
| 21:009:00 PM | 05:305:30 AM +1 day | |
| 22:0010:00 PM | 06:306:30 AM +1 day | |
| 23:0011:00 PM | 07:307:30 AM +1 day |
Quick conversion examples
These examples use BST (UTC+1) and ACST (UTC+9:30); choosing a date applies the local clock changes.
Conversion formula: ACST = BST + 8h30 · ACDT = GMT + 10h30 · ACDT = BST + 9h30.
| BST | ACST |
|---|---|
| 6:00 AM BST | = 2:30 PM ACST |
| 7:00 AM BST | = 3:30 PM ACST |
| 8:00 AM BST | = 4:30 PM ACST |
| 9:00 AM BST | = 5:30 PM ACST |
| 10:00 AM BST | = 6:30 PM ACST |
| 12:00 PM BST | = 8:30 PM ACST |
| 3:00 PM BST | = 11:30 PM ACST |
| 5:00 PM BST | = 1:30 AM ACST (+1 day) |
| 6:00 PM BST | = 2:30 AM ACST (+1 day) |
| 8:00 PM BST | = 4:30 AM ACST (+1 day) |
Overlapping meeting hours
The 08:00–18:00 working day in BST and ACST overlaps for 1 hour 30 minutes on 2026-10-21.
- Shared working hours
- 08:00–09:30 BST · 16:30–18:00 ACST
Clock changes on both sides, 2026–2028
BST and ACST have the following local clock changes in 2026–2028; all times in the table are local to that side.
| Year | BST | ACST |
|---|---|---|
| 2026 | · 01:00 → 02:00 · 02:00 → 01:00 | · 03:00 → 02:00 · 02:00 → 03:00 |
| 2027 | · 01:00 → 02:00 · 02:00 → 01:00 | · 03:00 → 02:00 · 02:00 → 03:00 |
| 2028 | · 01:00 → 02:00 · 02:00 → 01:00 | · 03:00 → 02:00 · 02:00 → 03:00 |
At the start of 2026, ACDT is 10 hours 30 minutes ahead of GMT. The difference changes during the following periods.
- From 2026-03-29 02:00 BST until 2026-04-04 17:30 BST, ACDT is 9 hours 30 minutes ahead of BST.
- From 2026-04-04 17:30 BST until 2026-10-03 17:30 BST, ACST is 8 hours 30 minutes ahead of BST.
- From 2026-10-03 17:30 BST until 2026-10-25 01:00 GMT, ACDT is 9 hours 30 minutes ahead of BST.
- From 2027-03-28 02:00 BST until 2027-04-03 17:30 BST, ACDT is 9 hours 30 minutes ahead of BST.
- From 2027-04-03 17:30 BST until 2027-10-02 17:30 BST, ACST is 8 hours 30 minutes ahead of BST.
- From 2027-10-02 17:30 BST until 2027-10-31 01:00 GMT, ACDT is 9 hours 30 minutes ahead of BST.
- From 2028-03-26 02:00 BST until 2028-04-01 17:30 BST, ACDT is 9 hours 30 minutes ahead of BST.
- From 2028-04-01 17:30 BST until 2028-09-30 17:30 BST, ACST is 8 hours 30 minutes ahead of BST.
- From 2028-09-30 17:30 BST until 2028-10-29 01:00 GMT, ACDT is 9 hours 30 minutes ahead of BST.
Frequently asked questions
What time is 9 AM BST in ACST?
9:00 AM BST = 5:30 PM ACST, using UTC+1 and UTC+9:30. Choose a date above for the seasonal local time.
Does the time difference between BST and ACST change during the year?
Yes. During 2026–2028: ACST is 8 hours 30 minutes ahead of BST; ACST is 9 hours 30 minutes ahead of BST; ACST is 10 hours 30 minutes ahead of BST. 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 BST and ACST?
The shared 08:00–18:00 working window is 08:00–09:30 UTC+1 / 16:30–18:00 ACST, a total of 1 hour 30 minutes.
What is the time difference between BST and ACST now?
Right now, ACST is 8 hours 30 minutes ahead of UTC+1. Conversion formula: ACST = BST + 8h30 · ACDT = GMT + 10h30 · ACDT = BST + 9h30.