What is ACST in GMT?

Greenwich Mean Time is 10 hours 30 minutes behind

Australian Central Time is on UTC+10:30 and Greenwich Mean Time is on UTC+0:00 right now. Australian Central Time is on daylight saving, so its clocks read ACDT. The gap changes during the year — see below.

Convert a time

ACDT — Australian Central Time

GMT — Greenwich Mean Time

7:30 am

GMT, Sat

Time in Adelaide: 6:59:05 PM
Time in Greenwich: 8:29:05 AM
Difference: −10:30 h
Next clock change: April 4, 2027

When the difference changes

Australian Central Time and Greenwich Mean 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 – April 4, 2027Greenwich Mean Time is 10 hours 30 minutes behind
April 4, 2027 – October 3, 2027Greenwich Mean Time is 9 hours 30 minutes behind
October 3, 2027 – onwardsGreenwich Mean Time is 10 hours 30 minutes behind

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

Australian Central Time

Sunday, April 4, 2027

Clocks go back one hour — 3:00 am becomes 2:00 am local time, and the zone is on ACST after that.

Greenwich Mean Time

No clock changes

Greenwich Mean Time stays on GMT all year, so its offset from UTC never moves.

ACST to GMT conversion table

Every hour of Saturday, November 7, 2026, converted from Australian Central Time to Greenwich Mean Time. 11 of the 24 hours fall on a different calendar day in Greenwich, which is marked.

12:00 am ACDT: 1:30 pm GMT−1 day
1:00 am ACDT: 2:30 pm GMT−1 day
2:00 am ACDT: 3:30 pm GMT−1 day
3:00 am ACDT: 4:30 pm GMT−1 day
4:00 am ACDT: 5:30 pm GMT−1 day
5:00 am ACDT: 6:30 pm GMT−1 day
6:00 am ACDT: 7:30 pm GMT−1 day
7:00 am ACDT: 8:30 pm GMT−1 day
8:00 am ACDT: 9:30 pm GMT−1 day
9:00 am ACDT: 10:30 pm GMT−1 day
10:00 am ACDT: 11:30 pm GMT−1 day
11:00 am ACDT: 12:30 am GMT

12:00 pm ACDT: 1:30 am GMT
1:00 pm ACDT: 2:30 am GMT
2:00 pm ACDT: 3:30 am GMT
3:00 pm ACDT: 4:30 am GMT
4:00 pm ACDT: 5:30 am GMT
5:00 pm ACDT: 6:30 am GMT
6:00 pm ACDT: 7:30 am GMT
7:00 pm ACDT: 8:30 am GMT
8:00 pm ACDT: 9:30 am GMT
9:00 pm ACDT: 10:30 am GMT
10:00 pm ACDT: 11:30 am GMT
11:00 pm ACDT: 12:30 pm GMT

Scheduling between the two

There is no overlap between a nine-to-six working day in Adelaide and one in Greenwich — the gap is too wide. A call has to sit early or late for one side. Early morning in Adelaide is the usual compromise, since that is late afternoon or evening in Greenwich.

Australian Central Time (ACDT) is used in South Australia and the Northern Territory, on a half-hour offset from the east coast

Greenwich Mean Time (GMT) is used in as a fixed UTC+0 offset. Note that the UK itself leaves GMT every summer — see British Time below.