From
MST / MDT
Time Converter
MST to AST Time Converter
Convert Mountain Time to Atlantic Time with a live clock and clean permalinks.
To
AST / ADT
When it is 7:30 AM in Mountain Time, it is 10:30 AM in Atlantic Time.
MST to AST at a glance
Atlantic Time is 3 hours ahead of Mountain Time. If someone gives you a time in Mountain Time, move the clock by 3 hours to read it in Atlantic Time. A 9:00 AM start in Denver becomes 12:00 PM in Halifax.
What Mountain Time covers
Mountain Time is used across the US and Canada in cities such as Denver and Calgary. It is useful when you work with logistics, field teams, or regional teams across the western half of North America.
What Atlantic Time covers
Atlantic Time is used in eastern Canada and parts of the Caribbean. Halifax is a common city reference for it. It matters when scheduling across North America and island markets farther east.
Quick answers
What is the time difference between MST and AST?
Atlantic Time is 3 hours ahead of Mountain Time.
What happens to a 3:00 PM meeting in MST?
It lands at 6:00 PM in AST.
Does daylight saving time matter for MST to AST?
Mountain Time and Atlantic Time are shown using the offsets that are active right now, so the result already reflects any daylight saving change in effect today.