Mountain Time to Eastern Time (MT to ET)
To convert Mountain Time to Eastern Time (MT to ET): in summer 9:00 AM MDT is 11:00 AM EDT, and in winter 9:00 AM MST is 11:00 AM EST. The gap holds all year, because both ends switch together.
In Eastern Daylight Time
- On a 24-hour clock
- 09:00 MDT is 11:00 EDT
- The offsets
- MDT is UTC-06:00, EDT is UTC-04:00
- Difference
- EDT is 2 hours ahead of MDT
- Date
- Same calendar day.
- This gap holds all year
- Both zones switch on the same dates, so they move together.
- MDT is only in force part of the year United States: daylight time starts the second Sunday in March, at 02:00 local time and ends the first Sunday in November, at 02:00 local time (Energy Policy Act of 2005, in force since 2007). In 2026 that is 2026-03-08 to 2026-11-01. Denver is on MST between those dates.
- otherwise MST, UTC-07:00
- Military time zone letters Z (Zulu) is UTC. A to M run east of Greenwich an hour apart, N to Y west, and J is left out. A letter names an offset, so a zone that switches to daylight time changes letter: EST is R, EDT is Q.
- MDT is S (Sierra), EDT is Q (Quebec)
- In every zone
- HST 05:00 AKST 06:00 PST 07:00 AKDT 07:00 MST 08:00 PDT 08:00 CST 09:00 MDT 09:00 EST 10:00 CDT 10:00 EDT 11:00 UTC 15:00 GMT 15:00 BST 16:00 CET 16:00 CEST 17:00 EET 17:00 EEST 18:00 MSK 18:00 IST 20:30 SGT 23:00 HKT 23:00 JST 00:00 AEST 01:00 AEDT 02:00 NZST 03:00 NZDT 04:00
How the Time Zone Converter works
MT means Mountain Time, whichever of its two offsets is in force: MST at UTC-07:00 in winter, and MDT at UTC-06:00 from the second Sunday in March to the first Sunday in November. ET means Eastern Time, whichever of its two offsets is in force: EST at UTC-05:00 in winter, and EDT at UTC-04:00 from the second Sunday in March to the first Sunday in November. So converting MT to ET is the same arithmetic all year: ET is 2 hours ahead of MT.
The gap between these two does not change during the year. Both ends switch to daylight saving on the same dates under the United States rule, so they move together: MST to EST in winter and MDT to EDT in summer are both 2 hours. Only the abbreviations change.
Worked through: in summer, 9:00 AM MDT is 11:00 AM EDT. In winter, 9:00 AM MST is 11:00 AM EST.
Two hours, all year, for Denver. Mountain time is where the generic name stops describing one clock. Most of Arizona does not observe daylight saving, so 'Mountain time' in Phoenix is UTC-7 all year: two hours behind New York in winter and three in summer. The Navajo Nation in north-east Arizona does switch, and the Hopi Reservation inside it does not, so the same drive can cross the line between daylight and standard time several times. This conversion uses the Mountain time that switches; for Phoenix, use the MST to EST page, which is right in winter and an hour short in summer.
MST to EST has its own page, and it is a different question. That page converts the abbreviations exactly as written, which is right when an invitation names a specific offset. This one converts the zone (the clock on the wall in Denver), which is almost always what someone typing MT to ET wants. The converter above is preset to the summer pairing, MDT to EDT, because that is in force for about eight months of the year; for a date between November and March, pick MST and EST in the lists instead.
Common times for this pair, summer and winter:
- 7:00 AM MDT is 9:00 AM EDT; in winter, 7:00 AM MST is 9:00 AM EST - 9:00 AM MDT is 11:00 AM EDT; in winter, 9:00 AM MST is 11:00 AM EST - 3:00 PM MDT is 5:00 PM EDT; in winter, 3:00 PM MST is 5:00 PM EST - 6:00 PM MDT is 8:00 PM EDT; in winter, 6:00 PM MST is 8:00 PM EST
Time Zone Converter FAQ
What is the time difference between MT and ET?
2 hours, all year: ET is 2 hours ahead of MT. In winter that is MST to EST and in summer MDT to EDT, and both pairings have the same gap because the two ends switch together.
What time is 9:00 AM MT in ET?
In summer, 9:00 AM MDT is 11:00 AM EDT. In winter, 9:00 AM MST is 11:00 AM EST.
Is MT the same as MST?
Only in winter. MT is Mountain Time, whichever offset is in force: MST at UTC-07:00 from the first Sunday in November until the second Sunday in March, and MDT at UTC-06:00 the rest of the time. MST written in July is, strictly, an hour away from the clock in Denver. That is why MT is the safer thing to write in an invitation that has to be right all year.
When does the difference between MT and ET change?
It does not. Both ends switch under the United States rule on the same dates (in 2026, 2026-03-08 and 2026-11-01), so the abbreviations change and the gap of 2 hours stays put.
Is there anything specific to this pair worth knowing?
Two hours, all year, for Denver. Mountain time is where the generic name stops describing one clock. Most of Arizona does not observe daylight saving, so 'Mountain time' in Phoenix is UTC-7 all year: two hours behind New York in winter and three in summer. The Navajo Nation in north-east Arizona does switch, and the Hopi Reservation inside it does not, so the same drive can cross the line between daylight and standard time several times. This conversion uses the Mountain time that switches; for Phoenix, use the MST to EST page, which is right in winter and an hour short in summer.
More from the Time Zone Converter
- Pacific Time to Eastern Time (PT to ET)
- Eastern Time to Pacific Time (ET to PT)
- Central Time to Eastern Time (CT to ET)
- Eastern Time to GMT (ET to GMT)
- UTC to Eastern Time (UTC to ET)
- Pacific Time to GMT (PT to GMT)
- Zulu time
- PST to EST