Convert any time between GMT and MDT, with a full 24-hour table and the hours when both sides are actually at work.

GMT to MDT Time Converter

MDT is 7 hours behind GMT. The UK and Ireland are currently on BST (UTC+1:00), and MDT is UTC-6:00.

Worth knowing right now. The UK and Ireland are currently on BST, not GMT, because daylight saving is in effect. The 7 hours above is the gap between those two regions today, which is almost certainly what you want. Taken strictly as written, GMT to MDT is 6 hours.
GMT
Greenwich Mean Time
04:45:38 PM
Sunday, October 11, 2026
UTC+1:00
-7:00
hours difference
⇆ Reverse
MDT
Mountain Daylight Time
09:45:38 AM
Sunday, October 11, 2026
UTC-6:00

Best Time to Call Between GMT and MDT

Both zones are inside normal business hours between 4:00 PM and 5:00 PM GMT — that's 9:00 AM to 10:00 AM MDT. That's a 1-hour window.

both at work GMT only MDT only neither  —  hours along the strip are GMT.

GMT to MDT: Full 24-Hour Conversion Table

Shaded rows are working hours; the darker shade marks the hours when both zones are at work.

GMTMDTWorking hours
12:00 AM 5:00 PM prev day —
1:00 AM 6:00 PM prev day —
2:00 AM 7:00 PM prev day —
3:00 AM 8:00 PM prev day —
4:00 AM 9:00 PM prev day —
5:00 AM 10:00 PM prev day —
6:00 AM 11:00 PM prev day —
7:00 AM 12:00 AM —
8:00 AM 1:00 AM —
9:00 AM 2:00 AM GMT only
10:00 AM 3:00 AM GMT only
11:00 AM 4:00 AM GMT only
12:00 PM 5:00 AM GMT only
1:00 PM 6:00 AM GMT only
2:00 PM 7:00 AM GMT only
3:00 PM 8:00 AM GMT only
4:00 PM 9:00 AM Both zones
5:00 PM 10:00 AM MDT only
6:00 PM 11:00 AM MDT only
7:00 PM 12:00 PM MDT only
8:00 PM 1:00 PM MDT only
9:00 PM 2:00 PM MDT only
10:00 PM 3:00 PM MDT only
11:00 PM 4:00 PM MDT only

What GMT and MDT Actually Are

GMT — Greenwich Mean Time

The UK and Ireland in winter, plus Iceland, Portugal and much of West Africa. Standing at UTC as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, October 25, 2026, to GMT. Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.

Britain ran an experiment from 1968 to 1971 on permanent UTC+1, abandoning GMT entirely. It was scrapped after complaints about dark winter mornings in Scotland.

MDT — Mountain Daylight Time

Denver, Salt Lake City, Calgary, Edmonton. Standing at UTC-6:00 as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, November 1, 2026, to MST.

Because Arizona does not follow it, MDT is the half of the year when Phoenix and Denver read the same clock despite being in different zones.

What This Means in Practice

Both sides change clocks, on different dates

Both regions observe daylight saving but do not switch on the same day, so for a week or two each spring and fall the gap between them is an hour different from the rest of the year. Those short windows are where recurring invitations quietly break.

Frequently Asked Questions

What is the time difference between GMT and MDT?

MDT is 7 hours behind GMT. That is the live figure. Taken strictly as written, the gap between GMT and MDT is 6 hours — the two differ because at least one of these regions is currently on daylight saving.

What is 9:00 AM GMT in MDT?

9:00 AM GMT is 2:00 AM MDT.

What are the best hours to schedule a call between GMT and MDT?

Between 4:00 PM and 5:00 PM GMT, which is 9:00 AM to 10:00 AM MDT. Both sides are inside normal business hours through that window.

Does the difference between GMT and MDT change during the year?

Yes. Both regions observe daylight saving, and they do not switch on the same dates, so the gap shifts by an hour at least twice a year. The next clock change is on Sunday, October 25, 2026.

Does GMT always mean Greenwich Mean Time?

Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.

Converting between two time zones regularly? Bookmark this page — the clocks update live and the table follows daylight saving automatically.