MDT to GMT Converter

Convert time between Mountain Daylight Time (MDT) and Greenwich Mean Time (GMT)

Mountain Daylight Time (MDT)

07:05:32
UTC +0
Dec 07, 2025
America/Denver

Greenwich Mean Time (GMT)

07:05:32
UTC +0
Dec 07, 2025
Europe/London

Time Difference

Greenwich Mean Time (GMT) is 0 hours ahead of Mountain Daylight Time (MDT)

Select Date

Select Time

Quick Reference

MDTGMT
19:0002:00
21:0004:00
23:0006:00
01:0008:00
03:0010:00
05:0012:00
07:0014:00
09:0016:00
11:0018:00
13:0020:00
15:0022:00
17:0000:00

Top 10 Most Common Time Zones

AbbreviationFull NameUTC OffsetTypical Use
UTCCoordinated Universal TimeUTC ±0Global reference standard (servers, logs, APIs)
EST / EDTEastern (US) TimeUTC −5 / −4New York, Toronto — North American business hub
CST / CDTCentral (US) TimeUTC −6 / −5Chicago, Dallas — US central business region
PST / PDTPacific (US) TimeUTC −8 / −7San Francisco, Los Angeles — tech industry standard
GMT / BSTGreenwich Mean / British Summer TimeUTC 0 / +1UK, used globally as a reference with UTC
CET / CESTCentral European (Summer) TimeUTC +1 / +2Paris, Berlin, Amsterdam — EU business core
ISTIndia Standard TimeUTC +5:30India — major IT & outsourcing region
CSTChina Standard TimeUTC +8Beijing, Shanghai — East Asia business hub
JSTJapan Standard TimeUTC +9Tokyo — finance & tech hub
AEST / AEDTAustralian Eastern (Daylight) TimeUTC +10 / +11Sydney, 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 OffsetRegion(s)
CSTCentral Standard Time / China Standard Time / Cuba Standard TimeUTC−6 / UTC+8 / UTC−5North America, China, Cuba
ISTIndian Standard Time / Irish Standard Time / Israel Standard TimeUTC+5:30 / UTC+1 / UTC+2India, Ireland, Israel
ASTAtlantic Standard Time / Arabia Standard TimeUTC−4 / UTC+3Caribbean, Canada, Middle East
PSTPacific Standard Time / Philippine Standard TimeUTC−8 / UTC+8North America, Philippines
ESTEastern Standard Time (North America / Australia)UTC−5 / UTC+10North America, Australia

✅ Best Practice

To avoid ambiguity, always:

  • Use IANA tz identifiers — e.g., America/New_York instead of "EST"
  • Specify UTC offset explicitly — e.g., UTC−5 when abbreviations must be used
  • Include the full timezone name — e.g., "Eastern Standard Time (EST)" with UTC offset

About MDT to GMT Time Conversion

Converting time from Mountain Daylight Time (MDT) to Greenwich Mean Time (GMT) is essential for coordinating between the US Mountain region and the United Kingdom during daylight saving time. MDT is UTC-6, while GMT is UTC+0, making GMT 6 hours ahead of MDT during the daylight saving period (March to November).

This converter uses the IANA timezone database to ensure accurate calculations for transatlantic business operations. Whether you're scheduling international meetings, managing distributed teams, or coordinating projects with the UK, this tool provides reliable real-time conversions for seamless global coordination during summer months.

Common Use Cases for MDT to GMT Conversion

Business & Work

  • Scheduling transatlantic business meetings between Mountain region and UK during summer
  • Coordinating with UK-based team members and remote workers
  • Managing international software development with London offices during daylight saving time
  • Syncing with London financial markets and trading operations during summer

Personal & Travel

  • Planning international travel from Mountain region to UK during summer
  • Coordinating with friends and family in the UK during daylight saving time
  • Attending UK-based conferences and virtual events during summer months
  • Tracking UK events and live broadcasts from Mountain region during daylight saving

Time Zone Information

Mountain Daylight Time (MDT)

  • UTC Offset: UTC-6
  • IANA Timezone: America/Denver
  • Daylight Saving: March to November (November to March uses MST)
  • Major Cities: Denver, Salt Lake City, Albuquerque, Boise, Colorado Springs
  • Coverage: Mountain United States and parts of Canada

Greenwich Mean Time (GMT)

  • UTC Offset: UTC+0
  • IANA Timezone: Europe/London
  • Daylight Saving: GMT is standard time (UTC+0). BST (UTC+1) is March to October
  • Major Cities: London, Greenwich, Edinburgh, Belfast, Cardiff
  • Coverage: United Kingdom, Ireland, and parts of Western Europe

Quick Reference: MDT to GMT

12:00 AM MDT
6:00 AM GMT
9:00 AM MDT
3:00 PM GMT
12:00 PM MDT
6:00 PM GMT
6:00 PM MDT
12:00 AM GMT (next day)

Note: GMT is always 6 hours ahead of MDT (March - November). During standard time (November - March), MST is UTC-7, making GMT 7 hours ahead.

Frequently Asked Questions

What is the time difference between MDT and GMT?

MDT (Mountain Daylight Time) is UTC-6, while GMT (Greenwich Mean Time) is UTC+0, making GMT 6 hours ahead of MDT. This means when it is noon in Denver (MDT), it is already 6:00 PM the same day in London (GMT).

How does MDT differ from MST?

MDT (Mountain Daylight Time) is UTC-6 and is observed during daylight saving time (March to November), while MST (Mountain Standard Time) is UTC-7 and is observed during standard time (November to March). This one-hour difference is important when scheduling across seasons.

Does GMT observe daylight saving time?

No, GMT (Greenwich Mean Time) does not observe daylight saving time. However, the UK uses BST (British Summer Time) during daylight saving periods. GMT remains UTC+0 year-round and is used as a global standard reference. During BST (late March to late October), the UK is UTC+1.

When does MDT change to MST?

Mountain Daylight Time (MDT) transitions to Mountain Standard Time (MST) on the first Sunday in November at 2:00 AM. The reverse transition from MST to MDT occurs on the second Sunday in March at 2:00 AM. During MST, the time difference with GMT is 7 hours instead of 6.

How do I convert MDT to GMT manually?

To convert MDT to GMT, simply add 6 hours to the MDT time. For example, if it is 3:00 PM MDT, the corresponding GMT time would be 9:00 PM (15:00 + 6 hours = 21:00). If the result exceeds 24 hours, subtract 24 hours and add 1 day.

Why is understanding MDT to GMT conversion important?

Understanding MDT to GMT conversion is crucial for coordinating with teams and businesses in the UK and Europe, international travel planning, virtual meetings across the Atlantic, and global communication. The 6-hour difference makes accurate conversion essential for business operations.

Pro Tips

  • • MDT is only observed from March to November. From November to March, the Mountain region uses MST (Mountain Standard Time) with a 7-hour difference from GMT.
  • • GMT is equivalent to UTC (Coordinated Universal Time) and serves as the global reference time used for aviation and international business.
  • • The UK switches to BST (British Summer Time) at the same dates as MDT transitions, so the time difference remains consistent during daylight saving overlaps.
  • • When scheduling international meetings between Mountain US and UK, early morning MDT (7-8 AM) aligns with 1-2 PM GMT, making it ideal for both regions.
  • • Use a converter like this one for daylight saving transitions to avoid miscalculations when MDT switches to MST and GMT switches to BST.
  • • Always verify whether your meeting participants are observing daylight saving time, as transition dates can vary between the US and UK by a few weeks.

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