GMT to MDT Converter
Understanding GMT and MDT Time Zones
Greenwich Mean Time (GMT)
Greenwich Mean Time is observed in undefined and uses the offset UTC+0. Major cities in this time zone include London, Dublin, Lisbon. This time zone covers parts of Europe and/or Africa, home to major financial and cultural centers.
Mountain Daylight Time (MDT)
Mountain Daylight Time operates at UTC-6, covering undefined. Key cities include Denver, Salt Lake City, Albuquerque. The 6-hour backward offset from GMT means that when professionals in London start their workday at 9:00 AM, it is already 3:00 AM in Denver.
GMT is also commonly referred to as London time, UK time, British time, England time. MDT is also known as Mountain Time, Mountain Daylight, MT, Denver time. So if you are searching for London time to Mountain Time, this is the same conversion as GMT to MDT.
Complete GMT to MDT Conversion Table
The table below shows every two-hour increment converted from Greenwich Mean Time to Mountain Daylight Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.
| GMT (Greenwich Mean Time) | MDT (Mountain Daylight Time) |
|---|---|
| 12:00 AM (00:00) | 6:00 PM (18:00) (previous day) |
| 2:00 AM (02:00) | 8:00 PM (20:00) (previous day) |
| 4:00 AM (04:00) | 10:00 PM (22:00) (previous day) |
| 6:00 AM (06:00) | 12:00 AM (00:00) |
| 8:00 AM (08:00) | 2:00 AM (02:00) |
| 10:00 AM (10:00) | 4:00 AM (04:00) |
| 12:00 PM (12:00) | 6:00 AM (06:00) |
| 2:00 PM (14:00) | 8:00 AM (08:00) |
| 4:00 PM (16:00) | 10:00 AM (10:00) |
| 6:00 PM (18:00) | 12:00 PM (12:00) |
| 8:00 PM (20:00) | 2:00 PM (14:00) |
| 10:00 PM (22:00) | 4:00 PM (16:00) |
Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.
Scheduling Between GMT and MDT
Freelancers and contractors working across GMT and MDT should clearly state their invoicing time zone. A 6-hour difference means an "end of business day" deliverable could mean very different things to each party.
The moderate 6-hour gap between GMT and MDT means that there is a partial overlap of business hours. Teams can typically find a 3–4 hour window that works for both sides without requiring anyone to work outside normal hours.
Travel Between London and Denver
For layover planning between undefined and undefined destinations, connecting flights often involve intermediate time zones. Use our converter to verify each leg independently to avoid missed connections.
Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 6-hour shift between GMT and MDT, plan for about 6 days to fully acclimate.
Daylight Saving Time Considerations
Some regions within a time zone do not observe DST. Arizona (MST) and Hawaii (HST) stay on standard time year-round, which can create unexpected offsets with neighboring states during summer months.
For the GMT to MDT conversion specifically: GMT (UTC+0) and MDT (UTC-6) both observe DST. When both zones transition on different dates, the offset temporarily shifts by one hour for a few weeks. Always verify during March–April and October–November.
Related Time Zone Conversions
References & Resources
Frequently Asked Questions
GMT (Greenwich Mean Time) is 6 hours ahead of MDT (Mountain Daylight Time). GMT is UTC+0 and MDT is UTC-6.
When it is 12:00 PM (noon) in GMT, it is 6:00 AM in MDT.
The best overlap for business hours is approximately 3:00 AM to 11:00 AM MDT, which corresponds to 9:00 AM to 5:00 PM in GMT.
Some regions within a time zone do not observe DST. Arizona (MST) and Hawaii (HST) stay on standard time year-round, which can create unexpected offsets with neighboring states during summer months.