Difference Wiki

EST vs. MST: What's the Difference?

Edited by Aimie Carlson || By Harlon Moss || Updated on October 4, 2023
EST is Eastern Standard Time, 5 hours behind Coordinated Universal Time (UTC-5), while MST is Mountain Standard Time, 7 hours behind UTC (UTC-7).

Key Differences

EST and MST are both time zones used in the United States, but they serve different geographic areas. EST primarily encompasses the East Coast, while MST covers parts of the West, particularly the mountainous regions.
The difference between EST and MST is two hours. When it's 12:00 PM in EST, it's 10:00 AM in MST. This difference is crucial for coordinating activities across states and ensuring synchronicity.
EST and MST experience shifts due to Daylight Saving Time. In summer, EST changes to Eastern Daylight Time (EDT), and MST switches to Mountain Daylight Time (MDT). This means both time zones adjust their clocks, but they maintain their two-hour difference.
While EST is the time standard for major cities like New York and Washington D.C., MST is the standard for cities like Phoenix and Denver. This geographical distinction impacts everything from TV broadcast schedules to flight timings.
It's essential for businesses and individuals interacting across these time zones to be aware of the EST and MST difference. This awareness ensures timely communication, prevents scheduling conflicts, and aids in efficient planning.

Comparison Chart

Geographic Coverage

Primarily East Coast of the US
Mountainous regions in the West of the US

UTC Offset


Daylight Saving Transition

Changes to Eastern Daylight Time (EDT)
Changes to Mountain Daylight Time (MDT)

Major Cities

New York, Washington D.C.
Phoenix, Denver

Time Difference with Each Other

2 hours ahead of MST
2 hours behind EST

EST and MST Definitions


Time zone 5 hours behind Coordinated Universal Time.
If it's 7:00 PM UTC, it's 2:00 PM in EST.


Time zone 7 hours behind Coordinated Universal Time.
If it's 7:00 PM UTC, it's 12:00 PM in MST.


Corresponds to the Eastern part of the United States.
Washington D.C. follows EST.


Mountain Standard Time zone in the U.S.
Denver operates on MST during the winter months.


Covers the U.S. East Coast and some parts of Canada.
Toronto in Canada also observes EST.


Covers specific regions of the U.S. and Canada.
Parts of Alberta in Canada observe MST.


Adjusts to EDT during Daylight Saving.
In spring, residents in the EST zone set their clocks an hour ahead.


Corresponds to the mountainous region of the Western U.S.
Arizona is predominantly in MST.


Eastern Standard Time zone in the U.S.
New York operates on EST during the winter months.


Adjusts to MDT during Daylight Saving, except in certain areas.
While Denver shifts to MDT, Phoenix doesn't change its clocks.


(obsolete) Grace; favour.


Mountain Standard Time, the time of the 105th meridian, used in the mountain states of the U.S.


Abbreviation of established


Standard time in the 7th time zone west of Greenwich, reckoned at the 105th meridian west; used in the mountain states of the United States


Init of w:Erhard Seminars Training, a course intended to promote satisfaction with life in the present moment, as opposed to strivings to attain it.




Standard time in the 5th time zone west of Greenwich, reckoned at the 75th meridian; used in the eastern United States


How many hours is EST behind UTC?

EST is 5 hours behind UTC.

What does EST stand for?

EST stands for Eastern Standard Time.

How is MST different from EST?

MST is two hours behind EST.

What states primarily observe MST?

States like Arizona and Colorado primarily observe MST.

Does MST always shift to MDT during Daylight Saving?

Most of MST does, but some areas, like most of Arizona, don't.

Do EST and MST cover regions outside the U.S.?

Yes, parts of Canada also observe EST and MST.

When coordinating a meeting between EST and MST, what should I consider?

Remember that MST is two hours behind EST.

What's the difference between Mountain Time and MST?

Mountain Time refers to the general time zone, including both MST and MDT, while MST specifically denotes the standard, non-daylight saving time.

When does EST change to EDT?

EST changes to EDT during Daylight Saving Time in spring.

Is EST ahead or behind MST?

EST is two hours ahead of MST.

How does Daylight Saving affect the difference between EST and MST?

Both zones adjust their clocks, but the two-hour difference remains.

Can a state decide to switch from MST to another time zone?

Technically, yes, but such changes require legal processes and are rare.

If I'm traveling from an EST region to an MST region, will I gain or lose time?

You'll gain two hours as MST is behind EST.

Which major cities are in the EST zone?

New York and Washington D.C. are examples of cities in the EST zone.

What's the UTC offset for MST?

MST is 7 hours behind UTC.

Why are time zones like EST and MST important?

They ensure synchronized activities across different geographic regions.

Which time zone comes after MST as we move westward?

Pacific Standard Time (PST) follows MST.

If it's 3:00 PM in MST, what time is it in EST?

It's 5:00 PM in EST.

Are there areas in MST that don't observe Daylight Saving?

Yes, most of Arizona doesn't observe Daylight Saving.

How do EST and MST affect TV broadcast schedules?

Broadcast times vary based on time zones, so a show might air at 8:00 PM EST and 6:00 PM MST.
About Author
Written by
Harlon Moss
Harlon is a seasoned quality moderator and accomplished content writer for Difference Wiki. An alumnus of the prestigious University of California, he earned his degree in Computer Science. Leveraging his academic background, Harlon brings a meticulous and informed perspective to his work, ensuring content accuracy and excellence.
Edited by
Aimie Carlson
Aimie Carlson, holding a master's degree in English literature, is a fervent English language enthusiast. She lends her writing talents to Difference Wiki, a prominent website that specializes in comparisons, offering readers insightful analyses that both captivate and inform.

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