Converter · ET → MT

EST to MST: Eastern to Mountain Time

Mountain Time is 2 hours behind Eastern Time: 9:00 AM EST is 7:00 AM MST in Denver. Arizona skips daylight saving, so Phoenix is 2 hours behind ET in winter and 3 hours behind in summer.

Now in Eastern Time
--:-- ET
Now in Denver
--:-- MT
Now in Phoenix
--:-- MST
Difference
Denver 2 hours behind · Phoenix 2–3 hours behind
Next change (ET & Denver)
Second Sunday in March

How many hours behind Eastern Time is Mountain Time?

Two hours, wherever Mountain Time observes daylight saving time: Colorado, Utah, New Mexico, Wyoming, Montana, southern Idaho, El Paso in Texas and the western parts of Kansas, Nebraska and the Dakotas. These places use MST (UTC−7) in winter and MDT (UTC−6) in summer, and they change clocks on the same Sundays as the East:

  • November to March: EST (UTC−5) vs MST (UTC−7) = 2 hours.
  • March to November: EDT (UTC−4) vs MDT (UTC−6) = 2 hours.

Arizona is the exception. It stays on MST all year, so when the East moves to EDT in March, Phoenix drops to 3 hours behind New York until November. During those months Phoenix shows the same time as Los Angeles (see EST to PST). The clocks at the top of this page show which case applies today; the live Eastern Time clock counts down to the next change.

Hours behind Eastern Time during 2027: Denver 2 hours all year; Phoenix 2 hours until March 14, 3 hours until November 7, then 2 hours again DenverPhoenix 2 h behind ET all year2 h3 h behind ET (no DST)2 h Mar 14Nov 7 JanMarMayJulSepNovDec
Denver changes clocks with New York; Phoenix does not.

MST or MDT: which one applies right now?

MST means UTC−7 and MDT means UTC−6 (the UTC offset guide explains the notation). At this moment Denver is on MST or MDT and Phoenix on MST. From November to March the two labels agree. In summer, "MST" correctly describes only Arizona and the other places that stay at UTC−7 all year.

That makes a July invitation for "10:00 AM MST" ambiguous. Read literally it means 10:00 AM in Phoenix, which is 11:00 AM in Denver; the sender may have meant Denver and simply used the familiar label. When an audience spans both states, write "MT" for the Rockies and name Arizona separately – for example "10:00 AM MT (9:00 AM Arizona)" in summer.

Why doesn't Arizona observe daylight saving time?

The Uniform Time Act of 1966 let any state exempt itself from daylight saving time by state law. Arizona observed DST in 1967, then on March 21, 1968 its legislature passed a law keeping the state on Mountain Standard Time all year. The usual explanation is the climate: in a desert summer, an extra hour of evening sun means more air-conditioning and a later start to the cool part of the day. The solar numbers show the effect. On July 15, 2027 the sun sets in Phoenix at 7:39 PM MST and is highest at 12:34 PM; on daylight time those would be 8:39 PM and 1:34 PM.

The exemption is not uniform across the state. The Navajo Nation, which extends into Utah and New Mexico, observes daylight saving time so that the whole reservation keeps one clock. The Hopi Reservation, entirely surrounded by Navajo land, follows the state and does not. A summer drive across northeastern Arizona can therefore cross several clock changes. South of the border, Arizona's neighbour Sonora has also stayed at UTC−7 all year since 1999.

EST to MST conversion tables

Pick the table for your date. Eastern times before 2:00 AM (3:00 AM for Phoenix in summer) fall on the previous day in Mountain Time.

November to March (ET on EST). Highlighted: 9:00 AM–5:00 PM in all three cities.
Eastern (EST)Denver (MST)Phoenix (MST)
12:00 AM10:00 PM (previous day)10:00 PM (previous day)
1:00 AM11:00 PM (previous day)11:00 PM (previous day)
2:00 AM12:00 AM12:00 AM
3:00 AM1:00 AM1:00 AM
4:00 AM2:00 AM2:00 AM
5:00 AM3:00 AM3:00 AM
6:00 AM4:00 AM4:00 AM
7:00 AM5:00 AM5:00 AM
8:00 AM6:00 AM6:00 AM
9:00 AM7:00 AM7:00 AM
10:00 AM8:00 AM8:00 AM
11:00 AM9:00 AM9:00 AM
12:00 PM10:00 AM10:00 AM
1:00 PM11:00 AM11:00 AM
2:00 PM12:00 PM12:00 PM
3:00 PM1:00 PM1:00 PM
4:00 PM2:00 PM2:00 PM
5:00 PM3:00 PM3:00 PM
6:00 PM4:00 PM4:00 PM
7:00 PM5:00 PM5:00 PM
8:00 PM6:00 PM6:00 PM
9:00 PM7:00 PM7:00 PM
10:00 PM8:00 PM8:00 PM
11:00 PM9:00 PM9:00 PM
March to November (ET on EDT). Highlighted: 9:00 AM–5:00 PM in all three cities.
Eastern (EDT)Denver (MDT)Phoenix (MST)
12:00 AM10:00 PM (previous day)9:00 PM (previous day)
1:00 AM11:00 PM (previous day)10:00 PM (previous day)
2:00 AM12:00 AM11:00 PM (previous day)
3:00 AM1:00 AM12:00 AM
4:00 AM2:00 AM1:00 AM
5:00 AM3:00 AM2:00 AM
6:00 AM4:00 AM3:00 AM
7:00 AM5:00 AM4:00 AM
8:00 AM6:00 AM5:00 AM
9:00 AM7:00 AM6:00 AM
10:00 AM8:00 AM7:00 AM
11:00 AM9:00 AM8:00 AM
12:00 PM10:00 AM9:00 AM
1:00 PM11:00 AM10:00 AM
2:00 PM12:00 PM11:00 AM
3:00 PM1:00 PM12:00 PM
4:00 PM2:00 PM1:00 PM
5:00 PM3:00 PM2:00 PM
6:00 PM4:00 PM3:00 PM
7:00 PM5:00 PM4:00 PM
8:00 PM6:00 PM5:00 PM
9:00 PM7:00 PM6:00 PM
10:00 PM8:00 PM7:00 PM
11:00 PM9:00 PM8:00 PM

What happens on the nights the clocks change?

Each zone switches at 2:00 AM local time, so Mountain Time changes two hours after Eastern Time. On Sunday, March 14, 2027, New York jumps to 3:00 AM EDT at 07:00 UTC while Denver is still at 12:00 AM MST. For the next two hours the gap is 3 hours, until Denver moves to MDT at 09:00 UTC. On Sunday, November 7, 2027 it shrinks to 1 hour between 06:00 and 08:00 UTC: 1:00 AM EST in New York is 12:00 AM MDT in Denver.

Phoenix has no transition of its own. Its gap to New York simply jumps from 2 to 3 hours when the East springs forward and drops back when the East falls back. The daylight saving time guide lists the dates through 2030, and EST to UTC shows the same instants in UTC.

Convert any Eastern time to Mountain Time

Denver is preselected; choose Phoenix for Arizona. Both sides' daylight saving rules are applied for the date you enter. More zones are on the time zone converter.

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What is the best meeting time between Eastern and Mountain Time?

Two 9-to-5 days overlap for six hours: 11:00 AM–5:00 PM ET, or 9:00 AM–3:00 PM in Denver. Arizona narrows it in summer to 12:00 PM–5:00 PM ET, because 11:00 AM in New York is then 8:00 AM in Phoenix. A slot of 1:00–3:00 PM ET works in every season for all three cities: 11:00 AM–1:00 PM in Denver, and 11:00 AM–1:00 PM (winter) or 10:00 AM–12:00 PM (summer) in Phoenix.

Create recurring invitations in a named zone (America/Denver or America/Phoenix) rather than a fixed offset, so that each one follows the right rule after March and November.

What changed for Mountain Time in Canada in 2026?

Alberta stopped changing clocks on November 1, 2026. It now keeps "Alberta Time" (ABT), UTC−6 all year – the offset it used to call Mountain Daylight Time. Calgary and Edmonton are therefore 1 hour behind Eastern Time from November to March and 2 hours behind from March to November: the opposite pattern to Arizona, and in winter the same clock as Chicago (see EST to CST). Yellowknife and Inuvik in the Northwest Territories moved with Alberta.

Yukon has stayed at UTC−7 since 2020, so Whitehorse matches Phoenix all year. If a device still shows the old winter time for Calgary, its time zone data predates the change and needs an update.

Frequently asked questions

What is 12:00 PM EST in MST?

10:00 AM MST. In summer, 12:00 PM EDT is 10:00 AM MDT in Denver but 9:00 AM MST in Phoenix.

Is Phoenix on the same time as Denver?

Only from November to March, when both use MST (UTC−7). From March to November Denver is on MDT and 1 hour ahead of Phoenix.

Is Phoenix on the same time as Los Angeles?

From March to November, yes: Phoenix's MST and Los Angeles' PDT are both UTC−7. In winter Phoenix is 1 hour ahead of Los Angeles.

Does Utah skip daylight saving time like Arizona?

No. Utah, Colorado, New Mexico and the other Mountain states change clocks on the federal schedule. Among the 50 states, only Arizona (outside the Navajo Nation) and Hawaii stay on standard time all year.

Which major cities use Mountain Time?

Denver, Salt Lake City, Albuquerque, Boise, El Paso and Colorado Springs switch between MST and MDT. Phoenix and Tucson stay on MST all year.

Explore

EST to CST

One hour behind, and three meanings of "CST".