EDT to MST Converter
Convert time between Eastern Daylight Time (EDT) and Mountain Standard Time (MST)
Eastern Daylight Time (EDT)
Mountain Standard Time (MST)
Time Difference
Mountain Standard Time (MST) is 0 hours ahead of Eastern Daylight Time (EDT)
Select Date
Select Time
Quick Reference
| EDT | MST |
|---|---|
| 21:00 | 19:00 |
| 23:00 | 21:00 |
| 01:00 | 23:00 |
| 03:00 | 01:00 |
| 05:00 | 03:00 |
| 07:00 | 05:00 |
| 09:00 | 07:00 |
| 11:00 | 09:00 |
| 13:00 | 11:00 |
| 15:00 | 13:00 |
| 17:00 | 15:00 |
| 19:00 | 17:00 |
Top 10 Most Common Time Zones
| Abbreviation | Full Name | UTC Offset | Typical Use |
|---|---|---|---|
| UTC | Coordinated Universal Time | UTC ±0 | Global reference standard (servers, logs, APIs) |
| EST / EDT | Eastern (US) Time | UTC −5 / −4 | New York, Toronto — North American business hub |
| CST / CDT | Central (US) Time | UTC −6 / −5 | Chicago, Dallas — US central business region |
| PST / PDT | Pacific (US) Time | UTC −8 / −7 | San Francisco, Los Angeles — tech industry standard |
| GMT / BST | Greenwich Mean / British Summer Time | UTC 0 / +1 | UK, used globally as a reference with UTC |
| CET / CEST | Central European (Summer) Time | UTC +1 / +2 | Paris, Berlin, Amsterdam — EU business core |
| IST | India Standard Time | UTC +5:30 | India — major IT & outsourcing region |
| CST | China Standard Time | UTC +8 | Beijing, Shanghai — East Asia business hub |
| JST | Japan Standard Time | UTC +9 | Tokyo — finance & tech hub |
| AEST / AEDT | Australian Eastern (Daylight) Time | UTC +10 / +11 | Sydney, Melbourne — APAC regional business |
Why Time Zone Abbreviations Are Ambiguous
Unlike standardized identifiers (like America/New_York or Europe/London from the IANA tz database), abbreviations such as "CST" or "IST" are not globally unique. They can refer to different time zones depending on context — country, region, or even time of year (due to daylight saving time).
Common Ambiguous Time Zone Abbreviations
| Abbrev. | Common Meaning(s) | UTC Offset | Region(s) |
|---|---|---|---|
| CST | Central Standard Time / China Standard Time / Cuba Standard Time | UTC−6 / UTC+8 / UTC−5 | North America, China, Cuba |
| IST | Indian Standard Time / Irish Standard Time / Israel Standard Time | UTC+5:30 / UTC+1 / UTC+2 | India, Ireland, Israel |
| AST | Atlantic Standard Time / Arabia Standard Time | UTC−4 / UTC+3 | Caribbean, Canada, Middle East |
| PST | Pacific Standard Time / Philippine Standard Time | UTC−8 / UTC+8 | North America, Philippines |
| EST | Eastern Standard Time (North America / Australia) | UTC−5 / UTC+10 | North America, Australia |
✅ Best Practice
To avoid ambiguity, always:
- Use IANA tz identifiers — e.g.,
America/New_Yorkinstead of "EST" - Specify UTC offset explicitly — e.g.,
UTC−5when abbreviations must be used - Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset
Related Time Zone Conversions
About EDT to MST Time Conversion
Converting time between Eastern Daylight Time (EDT) and Mountain Standard Time (MST) is useful for coordinating between the East Coast and Mountain regions. EDT is UTC-4 (used March to November), while MST is UTC-7 (November to March). EDT is exactly 3 hours ahead of MST. This conversion is particularly important during the winter months when the Mountain region is in standard time while the East Coast observes daylight saving time.
This converter is essential for business operations spanning New York, Philadelphia, and Eastern seaboard cities with Denver, Salt Lake City, Albuquerque, and other Mountain region locations. The 3-hour difference creates a manageable window for cross-region coordination, especially for tech companies and national retailers with distribution centers in both regions.
Common Use Cases for EDT to MST Conversion
Business & Work
- Scheduling meetings between East Coast offices and Mountain region operations
- Coordinating between New York headquarters and Denver/Salt Lake City branches
- Planning conference calls and webinars across East-to-Mountain regions
- Managing distributed teams across Eastern and Mountain time zones
- Coordinating supply chain and logistics for cross-region operations
Personal & Travel
- Planning travel between Eastern and Mountain time zones
- Coordinating with family and friends between regions
- Scheduling virtual events across East-to-Mountain participation
- Understanding local times in Mountain region destinations
- Managing time-sensitive appointments across regions
Time Zone Information
Eastern Daylight Time (EDT)
- UTC Offset: UTC-4 (UTC-5 during EST)
- IANA Timezone: America/New_York
- Daylight Saving: Second Sunday in March to First Sunday in November
- Major Cities: New York, Boston, Philadelphia, Atlanta, Miami, Washington DC
- Coverage: Eastern United States and Canada
Mountain Standard Time (MST)
- UTC Offset: UTC-7 (UTC-6 during MDT)
- IANA Timezone: America/Denver
- Daylight Saving: Second Sunday in March to First Sunday in November
- Major Cities: Denver, Salt Lake City, Albuquerque, Boise, Colorado Springs
- Coverage: Mountain United States and Canada
Quick Reference: EDT to MST
Remember: MST is always 3 hours behind EDT. Note: This is during winter months when Mountain region is in standard time (MST)
Frequently Asked Questions
What is the time difference between EDT and MST?
Eastern Daylight Time (EDT) is UTC-4, while Mountain Standard Time (MST) is UTC-7. This means EDT is 3 hours ahead of MST. When it's 12:00 PM in New York (EDT), it's 9:00 AM in Denver (MST).
When is EDT to MST conversion most relevant?
This conversion is most relevant during the winter months (November to March) when the Eastern region observes standard time transition while the Mountain region maintains MST. Note that outside this period, Mountain region switches to MDT (UTC-6), making the difference 2 hours instead of 3.
How does the EDT to MST difference affect business coordination?
The 3-hour difference creates a moderate coordination window. Morning meetings in the East (8-10 AM EDT) align with pre-dawn Mountain time (5-7 AM MST). Afternoon East Coast meetings (2-4 PM EDT) align with late morning Mountain time (11 AM-1 PM MST), making this a favorable window for cross-region calls.
What are the transition dates for EDT and MST?
EDT begins on the second Sunday in March and ends on the first Sunday in November. MST remains active from November through March. Both regions transition on the same November date, but the transition out of EDT and into MST happens on different dates in spring, affecting the comparison.
Why would companies coordinate between EDT and MST?
Major reasons include: headquarters on East Coast with operations/distribution centers in Mountain region (Denver, Salt Lake City), tech companies with Eastern offices and Rocky Mountain locations, national retailers coordinating supply chains, and media companies coordinating broadcast operations across regions.
What are the best meeting times for EDT to MST coordination?
Optimal windows: 8-10 AM EDT (5-7 AM MST) for early risers, 12-2 PM EDT (9-11 AM MST) for balanced timing, and 2-4 PM EDT (11 AM-1 PM MST) for afternoon meetings. The best window is 1-3 PM EDT (10 AM-12 PM MST) when both regions are in productive work hours.
Pro Tips
- • Use "2 PM ET / 12 PM MT" format when scheduling calls - this double notation prevents confusion and helps both regions understand exact timing.
- • The 3-hour difference means early morning is tough for Mountain region. Schedule calls after 9 AM MST (12 PM EDT) when Mountain teams are fully engaged.
- • Best coordination window: 1-3 PM EDT (10 AM-12 PM MST) gives peak productivity hours for both regions without extreme early mornings.
- • Remember MST is UTC-7: If you calculate UTC time from EDT (UTC-4), subtract 4 hours, then subtract 3 more for MST to verify conversions.
- • Document all meeting times in both EDT and MST on shared calendars. Google Calendar and Outlook both support multiple timezone display.
- • Plan quarterly reviews and annual meetings during overlap windows: 10 AM-2 PM EDT (7 AM-11 AM MST) requires minimal sacrifice from either region.
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