WIB to MST

About Western Indonesia Time

Indonesia spans three zones; WIB is the western one, at a fixed UTC+7, and it covers Jakarta, Sumatra and most of the population. Central Indonesia is an hour ahead and the east two, so "Indonesia time" is only unambiguous once you know which.

Cities on this clock: Jakarta, Bangkok, Ho Chi Minh City, Hanoi, Phnom Penh.

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.

How the difference is worked out

The gap between Western Indonesia Time and Mountain Time is not one number. The two zones change their clocks on different dates, so for part of the year the difference is 13 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 — Mountain Time is 14 hours behind Western Indonesia 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 Asia/Jakarta and America/Denver. Nothing is looked up on a server and nothing about your visit is recorded.