MST to EST Converter

Which MST and which EST?

Zone abbreviations are ambiguous, so this page starts by pinning both down. MST here is Mountain Standard Time (North America): the IANA zone America/Denver, anchored on Denver. Note that MST is also Mountain time as kept year-round in Phoenix, which does not observe DST; this page means only the Denver sense. EST here is Eastern Standard Time (North America): America/New_York, anchored on New York. Note that EST is also Australian Eastern Standard Time (usually written AEST); this page means only the New York sense.

MST in the everyday sense means Denver time, whichever of MST or MDT (Mountain Daylight Time) is in force. Denver is not on MST all year: its offset is UTC−7 while standard time applies (its January offset) and UTC−6 while daylight saving is active (its July offset). As of September 2026 it is on MDT (UTC−6). Wherever this page writes MST, read it as "Denver time on the date in question".

EST in the everyday sense means New York time, whichever of EST or EDT (Eastern Daylight Time) is in force. New York is not on EST all year: its offset is UTC−5 while standard time applies (its January offset) and UTC−4 while daylight saving is active (its July offset). As of September 2026 it is on EDT (UTC−4). Wherever this page writes EST, read it as "New York time on the date in question".

The difference as of September 2026

As of September 2026, New York is 2 hours ahead of Denver. Denver is on UTC−6 (MDT, daylight saving in effect) and New York is on UTC−4 (EDT, daylight saving in effect). Subtract one offset from the other and you have the gap. As wall clocks: 9:00 AM in Denver is 11:00 AM in New York, 5:00 PM in Denver is 7:00 PM in New York, and 9:00 AM in New York is 7:00 AM in Denver.

Next scheduled clock changes: clocks in Denver go back 1 hour on Sunday, November 1, 2026 (local date), moving the offset from UTC−6 to UTC−7; clocks in New York go back 1 hour on Sunday, November 1, 2026 (local date), moving the offset from UTC−4 to UTC−5. Neither change moves the gap, because the other side changes on the same date.

How the gap changes through the year

Both Denver and New York observe daylight saving — Denver moves between UTC−7 and UTC−6, New York between UTC−5 and UTC−4 — yet the gap between them never moves from one day to the next. Across the whole year scanned from Sep 7, 2026, the engine finds one unbroken run: New York is 2 hours ahead of Denver throughout.

The reason is that the two sides switch on the same dates. When clocks in Denver go forward by 1 hour, clocks in New York go forward by 1 hour on the same day, so the two offsets rise together and their difference is unchanged; the same happens in reverse when both fall back. The scan confirms it: there is no day in the year ahead on which one side has switched and the other has not. The next such shared date, as of September 2026: clocks in Denver go back 1 hour on Sunday, November 1, 2026 (local date), moving the offset from UTC−6 to UTC−7, and clocks in New York go back 1 hour on Sunday, November 1, 2026 (local date), moving the offset from UTC−4 to UTC−5.

This is why the pair feels simple — you can remember one number and it holds. It is also why that simplicity is conditional rather than structural. The gap is fixed only because both sides keep the same daylight-saving calendar. If either side changed its rules, whether by moving its dates or by stopping the seasonal shift altogether, the pair would immediately acquire a second gap for part of the year, exactly like the pairs on this site where only one side shifts. Nothing on this page assumes that will not happen: the schedule is recomputed from the tz database on every build, so a rule change would show up here as a new row rather than a stale number.

Working hours that overlap

Assume a 9:00 AM to 5:00 PM day on both sides. The gap never changes, so the overlap is the same all year:

• New York 2 hours ahead of Denver (MDT / EDT or MST / EST; 365 of the 365 days scanned): 6 hours of shared working time: 9:00 AM to 3:00 PM in Denver, which is 11:00 AM to 5:00 PM in New York.

The 9-to-5 window is a convention, not a fact about anyone's real hours. The Meeting Planner lets you set each side's actual working hours and shows the overlap for the exact date you are planning.

Converting EST to MST

This page serves both directions, because the reverse conversion is the same gap with the sign flipped. As of September 2026, Denver is 2 hours behind New York, so:

• 9:00 AM MST (Denver) = 11:00 AM EST (New York)
• 9:00 AM EST (New York) = 7:00 AM MST (Denver)
• 5:00 PM EST (New York) = 3:00 PM MST (Denver)

To run EST to MST in the converter above, swap the From and To menus; the result shows both offsets for the date you enter and flags a day change whenever the reading lands on the previous or next calendar day. Because the gap never moves, these readings hold in every season.

More on these zones

• Current time in Denver — live clock, offset and next clock change.
• Current time in New York — live clock, offset and next clock change.
• Time Zone Converter — any city to any city, DST-correct for the date.
• Meeting Planner — overlap for your real working hours.
• All zone-to-zone converters — the other corridors on this site.

MST to EST — frequently asked questions

Conversions are computed locally in your browser from its IANA time zone data; nothing you enter is transmitted. The schedule and offsets on this page were derived from the same database at build time, as of September 2026. Jurisdictions occasionally change DST law with short notice, and the IANA database follows reality — for legally critical timing, confirm against an official source. See the methodology page.