MST to EST converter
Eastern Time is 2 hours ahead of Mountain Time year-round: Mountain Time runs at UTC−7 / UTC−6 and Eastern Time at UTC−5 / UTC−4. To convert MST to EST, add 2 hours to the MST time. Both zones shift by an hour on the same dates, so the gap never moves.
Mountain Time runs at UTC−7 / UTC−6, Eastern Time at UTC−5 / UTC−4.
MST to EST conversion table
Every hour of the day converted. One column is enough here: the gap between the two zones is the same in winter and summer.
| Mountain Time (MST / MDT) | Eastern Time (EST / EDT) |
|---|---|
| 00:00 12:00 AM | 02:00 2:00 AM |
| 01:00 1:00 AM | 03:00 3:00 AM |
| 02:00 2:00 AM | 04:00 4:00 AM |
| 03:00 3:00 AM | 05:00 5:00 AM |
| 04:00 4:00 AM | 06:00 6:00 AM |
| 05:00 5:00 AM | 07:00 7:00 AM |
| 06:00 6:00 AM | 08:00 8:00 AM |
| 07:00 7:00 AM | 09:00 9:00 AM |
| 08:00 8:00 AM | 10:00 10:00 AM |
| 09:00 9:00 AM | 11:00 11:00 AM |
| 10:00 10:00 AM | 12:00 12:00 PM |
| 11:00 11:00 AM | 13:00 1:00 PM |
| 12:00 12:00 PM | 14:00 2:00 PM |
| 13:00 1:00 PM | 15:00 3:00 PM |
| 14:00 2:00 PM | 16:00 4:00 PM |
| 15:00 3:00 PM | 17:00 5:00 PM |
| 16:00 4:00 PM | 18:00 6:00 PM |
| 17:00 5:00 PM | 19:00 7:00 PM |
| 18:00 6:00 PM | 20:00 8:00 PM |
| 19:00 7:00 PM | 21:00 9:00 PM |
| 20:00 8:00 PM | 22:00 10:00 PM |
| 21:00 9:00 PM | 23:00 11:00 PM |
| 22:00 10:00 PM | 00:00 12:00 AM next day |
| 23:00 11:00 PM | 01:00 1:00 AM next day |
How the MST to EST conversion works
Converting MST to EST means taking a wall-clock time in Mountain Time (MST / MDT, UTC−7 / UTC−6) and expressing the same instant in Eastern Time (EST / EDT, UTC−5 / UTC−4). The arithmetic is one step: add 2 hours to any MST time, and it holds on every date of the year. Applying the gap pushes part of the day onto a different calendar date — the table below marks every row that shifts. In code, store the instant in UTC and convert with the IANA identifiers America/Denver and America/New_York, never with the abbreviations. One note on the source label: MST covers America/Denver, which shifts to MDT in summer, and America/Phoenix, which does not shift at all. On the target label: EST is also used for Australian Eastern Standard Time (UTC+10), so the abbreviation alone is ambiguous. A bare "09:00" carries no offset and means nothing until you attach the zone it belongs to.
Best time for meetings between MST and EST
Working hours are taken as 09:00–18:00 in each zone. The window in force depends on the date, so both halves of the year are listed where they differ.
EST / EDT, year-round
A 9-to-6 working day in both zones overlaps for 7 hours: 9:00 AM–4:00 PM MST is 11:00 AM–6:00 PM EST. Book inside that window and neither side is working outside normal hours.
Daylight saving time: which side moves
Both Mountain Time and Eastern Time shift their clocks on the same dates, by the same hour, in the same direction. The gap between them therefore holds at 2 hours on every date, including the two transition weekends.
US daylight saving time runs from the second Sunday in March to the first Sunday in November. Arizona is the exception: most of the state stays on MST year-round and never shifts to MDT.
- Mountain Time
- America/Denver
- MST / MDT — UTC−7 / UTC−6
- Eastern Time
- America/New_York
- EST / EDT — UTC−5 / UTC−4
Frequently asked questions
What is the time difference between MST and EST?
Eastern Time runs 2 hours ahead of Mountain Time on every date of the year. In offset terms, Mountain Time sits at UTC−7 / UTC−6 and Eastern Time at UTC−5 / UTC−4. So 9:00 AM MST is 11:00 AM EST. The hour-by-hour table on this page lists the conversion for all 24 hours so you do not have to do the arithmetic.
Does the MST to EST difference change with daylight saving time?
The difference holds at 2 hours on every date. Both Mountain Time and Eastern Time shift by an hour on the same dates and in the same direction, so the gap between them never moves, not even across a transition weekend. In the US that means clocks move forward on the second Sunday of March and back on the first Sunday of November.
What time is 9 am MST in EST?
9:00 AM MST is 11:00 AM in Eastern Time, and it stays that way all year because the two zones stay 2 hours apart. The rule is the same one the whole page runs on: add 2 hours to any MST time. Check the hour-by-hour table for any other starting hour, including the rows that land on the previous or next calendar day.
What do MST and EST stand for?
MST stands for Mountain Standard Time, and MDT is Mountain Daylight Time. EST stands for Eastern Standard Time, and EDT is Eastern Daylight Time. Both are display labels rather than rules: the offsets behind them come from the IANA identifiers America/Denver and America/New_York. MST covers America/Denver, which shifts to MDT in summer, and America/Phoenix, which does not shift at all.
Related conversions
Need more than two zones at once? The full timezone converter shows a single moment across up to six IANA timezones, for any date you choose.