What is AST in ACST?
Australian Central Time is 12 hours 30 minutes ahead
Atlantic Time is on UTC−3:00 and Australian Central Time is on UTC+9:30 right now. Atlantic Time is on daylight saving, so its clocks read ADT. The gap changes during the year — see below.
- Time in Halifax
- 9:03:41 AM
- Time in Adelaide
- 9:33:41 PM
- Difference
- +12:30 h
- Next clock change
- October 4, 2026
Convert a time
ACST — Australian Central Time
9:30 pm
ACST, Fri
When the difference changes
Atlantic Time and Australian Central Time do not change their clocks on the same dates, so the gap between them is not the same all year. Most converters show only today’s figure. These are the periods ahead:
- Now – October 3, 2026Australian Central Time is 12 hours 30 minutes ahead
- October 3, 2026 – November 1, 2026Australian Central Time is 13 hours 30 minutes ahead
- November 1, 2026 – March 14, 2027Australian Central Time is 14 hours 30 minutes ahead
- March 14, 2027 – April 3, 2027Australian Central Time is 13 hours 30 minutes ahead
- April 3, 2027 – October 2, 2027Australian Central Time is 12 hours 30 minutes ahead
- October 2, 2027 – onwardsAustralian Central Time is 13 hours 30 minutes ahead
Periods shorter than a day are not listed. Each zone changes at its own local time, so on a date when both move there are a few hours when the gap is briefly something else.
Daylight saving
Atlantic Time
Clocks go back one hour — 2:00 am becomes 1:00 am local time, and the zone is on AST after that.
Australian Central Time
Clocks go forward one hour — 2:00 am becomes 3:00 am local time, and the zone is on ACDT after that.
AST to ACST conversion table
Every hour of Friday, September 25, 2026, converted from Atlantic Time to Australian Central Time. 12 of the 24 hours fall on a different calendar day in Adelaide, which is marked.
- 12:00 am ADT
- 12:30 pm ACST
- 1:00 am ADT
- 1:30 pm ACST
- 2:00 am ADT
- 2:30 pm ACST
- 3:00 am ADT
- 3:30 pm ACST
- 4:00 am ADT
- 4:30 pm ACST
- 5:00 am ADT
- 5:30 pm ACST
- 6:00 am ADT
- 6:30 pm ACST
- 7:00 am ADT
- 7:30 pm ACST
- 8:00 am ADT
- 8:30 pm ACST
- 9:00 am ADT
- 9:30 pm ACST
- 10:00 am ADT
- 10:30 pm ACST
- 11:00 am ADT
- 11:30 pm ACST
- 12:00 pm ADT
- 12:30 am ACST+1 day
- 1:00 pm ADT
- 1:30 am ACST+1 day
- 2:00 pm ADT
- 2:30 am ACST+1 day
- 3:00 pm ADT
- 3:30 am ACST+1 day
- 4:00 pm ADT
- 4:30 am ACST+1 day
- 5:00 pm ADT
- 5:30 am ACST+1 day
- 6:00 pm ADT
- 6:30 am ACST+1 day
- 7:00 pm ADT
- 7:30 am ACST+1 day
- 8:00 pm ADT
- 8:30 am ACST+1 day
- 9:00 pm ADT
- 9:30 am ACST+1 day
- 10:00 pm ADT
- 10:30 am ACST+1 day
- 11:00 pm ADT
- 11:30 am ACST+1 day
Scheduling between the two
There is no overlap between a nine-to-six working day in Halifax and one in Adelaide — the gap is too wide. A call has to sit early or late for one side. Early morning in Halifax is the usual compromise, since that is late afternoon or evening in Adelaide.
A note on AST: it can also mean Arabia Standard Time (UTC+3). This page means Atlantic Time.
Atlantic Time (ADT) is used in Nova Scotia, New Brunswick and Puerto Rico
Australian Central Time (ACST) is used in South Australia and the Northern Territory, on a half-hour offset from the east coast
Other conversions
- ACST to AST
- AST to UTC
- AST to GMT
- AST to EST
- AST to CST
- AST to MST
- AST to PST
- AST to AKST
- AST to HST
- AST to BST
- AST to CET
- AST to IST
- AST to CST (China)
- AST to JST
- AST to AEST
- AST to Mexico City
- AST to BRT
- AST to ART
- AST to EET
- AST to WET
- AST to MSK
- AST to TRT
- AST to SAST
- AST to WAT
- AST to EAT
- AST to GST
- AST to PKT
- AST to ICT
- AST to WIB
- AST to SGT
- AST to HKT
- AST to KST
- AST to PHT
- AST to AWST
- AST to NZST
- All zones