There is no overlap between 09:00–18:00 working days in these two places.
How many hours is GMT behind ACDT?
As abbreviations, ACDT is always 10.5 hours ahead of GMT: GMT is UTC+0 and ACDT is UTC+10:30. To convert, add 10.5 hours.
When the GMT to ACDT time difference changes
For most of the year ACDT is 9.5 hours ahead of GMT. From 4 October to 31 December 2026, ACDT is 10.5 hours ahead of GMT 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
ACDT vs GMT
Length
4 October 2026 to 31 December 2026
10.5 hours ahead
89 days
1 January 2027 to 3 April 2027
10.5 hours ahead
93 days
4 April 2027 to 2 October 2027
9.5 hours ahead
182 days
3 October 2027 to 31 December 2027
10.5 hours ahead
90 days
Best time for a meeting between GMT and ACDT
When ACDT is 9.5 hours ahead of GMT: no shared 09:00 to 17:00 hours; try 08:00 in GMT (17:30 in ACDT).
When ACDT is 10.5 hours ahead of GMT: no shared 09:00 to 17:00 hours; try 07:00 in GMT (17:30 in ACDT).
Frequently asked questions about GMT and ACDT time
How many hours ahead is ACDT of GMT?
ACDT (UTC+10:30) is 10.5 hours ahead of GMT (UTC+0).
Does the time difference between GMT and ACDT change?
Yes. It is usually 9.5 hours ahead, but changes when one side moves its clocks: 10.5 hours ahead from 4 October to 31 December 2026; 10.5 hours ahead from 1 January to 3 April 2027.