ACST to MST Converter

Standard business hours (9 AM–5 PM, Mon–Fri) in Australian Central Time and Mountain Time don't overlap on the same weekday. Mountain Time is 15 hours behind Australian Central Time.

Realistic options: hand off asynchronously, or stretch one side by an hour to catch the other team at the start or end of their day.

Australian Central Time is also known as ACST, or ACDT. To call Australia, dial +61.

Mountain Time is also known as MST, or MDT. To call United States, dial +1.

Mountain Time is approximately 9,000 miles northeast of Australian Central Time.

Both zones observe daylight saving time, but they transition on different dates.

Australian Central Time: next transition on Sunday, October 4, 2026.

Mountain Time: next transition on Sunday, November 1, 2026.

Australian Central Time and Mountain Time are in opposite hemispheres, so their clocks change in opposite directions about six months apart — one springs forward while the other falls back. The offset between them therefore shifts twice a year and can swing by up to two hours across the seasons, more than a typical same-hemisphere pair. Recurring meetings will need re-checking after each transition.

See the daylight saving time page for transition dates across every time zone.