Convert GST to ACST
ACST is 5 hours 30 minutes ahead of GST. GST is UTC+4 and ACST is UTC+9:30.
Right now: GST · ACST
Best time to schedule a meeting
Standard 9–5 working hours overlap for 3 hours: 9:00 AM–12:00 PM GST (2:00 PM–5:00 PM ACST). Schedule meetings inside that window.
| GST | ACST | Suitable? |
|---|---|---|
| 9:00 AM | 2:30 PM | working hours |
| 10:00 AM | 3:30 PM | working hours |
| 11:00 AM | 4:30 PM | working hours |
| 12:00 PM | 5:30 PM | outside 9–5 |
| 1:00 PM | 6:30 PM | outside 9–5 |
| 2:00 PM | 7:30 PM | outside 9–5 |
| 3:00 PM | 8:30 PM | outside 9–5 |
| 4:00 PM | 9:30 PM | outside 9–5 |
| 5:00 PM | 10:30 PM | outside 9–5 |
GST to ACST conversion table
| GST | ACST |
|---|---|
| 12:00 AM | 5:30 AM |
| 1:00 AM | 6:30 AM |
| 2:00 AM | 7:30 AM |
| 3:00 AM | 8:30 AM |
| 4:00 AM | 9:30 AM |
| 5:00 AM | 10:30 AM |
| 6:00 AM | 11:30 AM |
| 7:00 AM | 12:30 PM |
| 8:00 AM | 1:30 PM |
| 9:00 AM | 2:30 PM |
| 10:00 AM | 3:30 PM |
| 11:00 AM | 4:30 PM |
| 12:00 PM | 5:30 PM |
| 1:00 PM | 6:30 PM |
| 2:00 PM | 7:30 PM |
| 3:00 PM | 8:30 PM |
| 4:00 PM | 9:30 PM |
| 5:00 PM | 10:30 PM |
| 6:00 PM | 11:30 PM |
| 7:00 PM | 12:30 AM (next day) |
| 8:00 PM | 1:30 AM (next day) |
| 9:00 PM | 2:30 AM (next day) |
| 10:00 PM | 3:30 AM (next day) |
| 11:00 PM | 4:30 AM (next day) |
About GST
Gulf Standard Time (GST) is UTC+4. It is used in Dubai, Abu Dhabi and Muscat.
Gulf Standard Time is UTC+4, covering the United Arab Emirates and Oman, and there is no daylight saving anywhere on the Arabian peninsula. The scheduling complication in the region is not the clock but the week: the UAE moved its weekend to Saturday–Sunday in 2022, while Saudi Arabia and several neighbours keep Friday–Saturday, so a Thursday afternoon meeting lands differently across a border that has no time difference at all.
About ACST
Australian Central Standard Time (ACST) is UTC+9:30. It is used in Adelaide and Darwin in winter.
Australian Central Standard Time is UTC+9:30, half an hour behind the eastern states rather than a whole hour, which surprises people every time. South Australia moves to daylight saving in October and the Northern Territory does not, so Adelaide and Darwin share this offset for half the year and are an hour apart for the other half.
Does this gap change with the seasons?
Neither GST nor ACST shifts with the seasons, so this 5.5-hour difference holds all year. That is unusual enough to be worth relying on: most cross-continental gaps move twice a year.
This is the reason scheduling systems store an IANA zone such as Region/City rather than an offset or an abbreviation: the zone knows its own rules and the offset does not.
Frequently asked questions
What time is 9:00 AM GST in ACST?
9:00 AM GST is 2:30 PM ACST.
Is ACST ahead of GST?
ACST is 5 hours 30 minutes ahead of GST.
Which time zone does this use?
GST is UTC+4 and ACST is UTC+9:30. Both abbreviations denote a single fixed offset, so this conversion never shifts with daylight saving — what changes is which abbreviation a place is using at the time.