MST to AEST

About Mountain Time

Mountain Time is UTC−7 as MST and UTC−6 as MDT, on the same transition dates as the rest of the United States. Arizona is the exception worth knowing: almost all of it stays on MST all year, so for the eight months the rest of the zone is on MDT, Phoenix keeps the same clock as Los Angeles rather than Denver.

Cities on this clock: Denver, Salt Lake City, Calgary, Edmonton.

About Australian Eastern Time

Sydney, Melbourne and Canberra run at UTC+10 as AEST and UTC+11 as AEDT, changing on the first Sunday in October and the first Sunday in April. Queensland does not change at all, so Brisbane matches Sydney for about half the year and sits an hour behind it for the rest — on the same "Eastern" label.

Cities on this clock: Sydney, Melbourne.

How the difference is worked out

The gap between Mountain Time and Australian Eastern Time is not one number. The two zones change their clocks on different dates, so for part of the year the difference is 16 hours and for the rest it is something else — the table above lists each stretch of 2026 with the date it starts and which country's clocks moved.

With both zones on their own standard time — daylight saving not in force anywhere — Australian Eastern Time is 17 hours ahead of Mountain Time. That figure never changes; everything else on this page follows from it plus whichever clocks have moved.

Every figure here comes from the IANA time zone database via your browser's own Intl engine, using the zone ids America/Denver and Australia/Sydney. Nothing is looked up on a server and nothing about your visit is recorded.