Highlighted rows fall within 09:00–18:00 in both places: 1 shared working hour.
How many hours is CET behind ACST?
As abbreviations, ACST is always 8.5 hours ahead of CET: CET is UTC+1 and ACST is UTC+9:30. To convert, add 8.5 hours.
When the CET to ACST time difference changes
For most of the year ACST is 7.5 hours ahead of CET. From 25 October to 31 December 2026, ACST is 8.5 hours ahead of CET instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
Dates
ACST vs CET
Length
25 October 2026 to 31 December 2026
8.5 hours ahead
68 days
1 January 2027 to 27 March 2027
8.5 hours ahead
86 days
28 March 2027 to 30 October 2027
7.5 hours ahead
217 days
31 October 2027 to 31 December 2027
8.5 hours ahead
62 days
Best time for a meeting between CET and ACST
When ACST is 7.5 hours ahead of CET: 1 shared office hour, 09:00 to 10:00 in CET (16:30 to 17:30 in ACST).
When ACST is 8.5 hours ahead of CET: no shared 09:00 to 17:00 hours; try 09:00 in CET (17:30 in ACST).
Frequently asked questions about CET and ACST time
How many hours ahead is ACST of CET?
ACST (UTC+9:30) is 8.5 hours ahead of CET (UTC+1).
Does the time difference between CET and ACST change?
Yes. It is usually 7.5 hours ahead, but changes when one side moves its clocks: 8.5 hours ahead from 25 October to 31 December 2026; 8.5 hours ahead from 1 January to 27 March 2027.