EST to MST Time Converter
MST is 2 hours behind EST. The US East Coast is currently on EDT (UTC-4:00), and The US Mountain states are currently on MDT (UTC-6:00).
Best Time to Call Between EST and MST
Both zones are inside normal business hours between 11:00 AM and 5:00 PM EST — that's 9:00 AM to 3:00 PM MST. That's a 6-hour window.
both at work EST only MST only neither — hours along the strip are EST.
Common Times Converted
EST on the left, MST on the right.
EST to MST: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| EST | MST | Working hours |
|---|---|---|
| 12:00 AM | 10:00 PM prev day | — |
| 1:00 AM | 11:00 PM prev day | — |
| 2:00 AM | 12:00 AM | — |
| 3:00 AM | 1:00 AM | — |
| 4:00 AM | 2:00 AM | — |
| 5:00 AM | 3:00 AM | — |
| 6:00 AM | 4:00 AM | — |
| 7:00 AM | 5:00 AM | — |
| 8:00 AM | 6:00 AM | — |
| 9:00 AM | 7:00 AM | EST only |
| 10:00 AM | 8:00 AM | EST only |
| 11:00 AM | 9:00 AM | Both zones |
| 12:00 PM | 10:00 AM | Both zones |
| 1:00 PM | 11:00 AM | Both zones |
| 2:00 PM | 12:00 PM | Both zones |
| 3:00 PM | 1:00 PM | Both zones |
| 4:00 PM | 2:00 PM | Both zones |
| 5:00 PM | 3:00 PM | MST only |
| 6:00 PM | 4:00 PM | MST only |
| 7:00 PM | 5:00 PM | — |
| 8:00 PM | 6:00 PM | — |
| 9:00 PM | 7:00 PM | — |
| 10:00 PM | 8:00 PM | — |
| 11:00 PM | 9:00 PM | — |
What EST and MST Actually Are
EST — Eastern Standard Time
New York, Toronto, Washington DC, Atlanta, Miami, Boston. Standing at UTC-5:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to EST. Australia also uses EST for its own Eastern Standard Time (UTC+10), now more often written AEST.
Eastern Standard Time is only actually in force from early November to mid-March. For the other eight months the same region is on EDT, which is why so many EST conversions are quietly wrong.
MST — Mountain Standard Time
Denver, Salt Lake City, Calgary — and Phoenix year-round. Standing at UTC-7:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to MST. Arizona stays on MST all year, so Phoenix and Denver are an hour apart for eight months and identical for four.
Arizona has stayed on MST year-round since 1968 — the Navajo Nation within it does observe daylight saving, making the state a patchwork.
What This Means in Practice
Both sides change clocks, on different dates
Both regions observe daylight saving but do not switch on the same day, so for a week or two each spring and fall the gap between them is an hour different from the rest of the year. Those short windows are where recurring invitations quietly break.
Close enough to share a working day
At only 2 hours apart, the two working days overlap almost completely. Scheduling is barely constrained by the difference.
Major Cities in Each Zone
Cities on EST
Cities on MST
Frequently Asked Questions
What is the time difference between EST and MST?
MST is 2 hours behind EST.
What is 9:00 AM EST in MST?
9:00 AM EST is 7:00 AM MST.
What are the best hours to schedule a call between EST and MST?
Between 11:00 AM and 5:00 PM EST, which is 9:00 AM to 3:00 PM MST. Both sides are inside normal business hours through that window.
Does the difference between EST and MST change during the year?
Yes. Both regions observe daylight saving, and they do not switch on the same dates, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, November 1, 2026.
Does EST always mean Eastern Standard Time?
Australia also uses EST for its own Eastern Standard Time (UTC+10), now more often written AEST.
Does MST always mean Mountain Standard Time?
Arizona stays on MST all year, so Phoenix and Denver are an hour apart for eight months and identical for four.