MST to GMT
Denver to London.
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All date & timeQuestions
What time is GMT when it is 12:00 MST?
19:00. Greenwich Mean Time is 7 hours ahead of Mountain Time, all year round. A 9-to-5 day in Denver overlaps a 9-to-5 day in London for one hour, between 09:00 and 10:00 MST.
Is the difference between MST and GMT the same all year?
Yes. Greenwich Mean Time is 7 hours ahead of Mountain Time, all year round. Both zones change their clocks, and close enough to the same dates that the gap between them holds — apart from a week or two each spring and autumn when one has shifted and the other has not.
What do MST and GMT actually stand for?
MST is Mountain Time, the zone covering Denver, currently UTC−7 in January. GMT is Greenwich Mean Time, covering London, at UTC+0. Arizona sits in this zone but does not change its clocks, so for eight months of the year Phoenix matches Los Angeles rather than Denver. It is the most common source of a missed call in North American scheduling.
Anything worth knowing about Greenwich Mean Time?
GMT and UK time are the same thing only in winter. From late March to late October London runs on British Summer Time, an hour ahead of GMT, so a meeting booked as 'GMT' with someone in London is an hour out for most of the year.
When is a good time to call between Denver and London?
A 9-to-5 day in Denver overlaps a 9-to-5 day in London for one hour, between 09:00 and 10:00 MST. If the call has to happen outside that, the fairer arrangement is usually to alternate which side takes the awkward hour rather than always asking the same one.
How it works, and more about mst → gmt
The difference, and whether you can rely on it
In January, Greenwich Mean Time is 7 hours ahead of Mountain Time — UTC−7 against UTC+0. It stays that way all year, so the number is worth memorising if you work across these two often.
When you can both be at a desk
A standard working day in Denver overlaps one in London between 09:00 and 10:00 MST — 1 hours. Anything outside that asks somebody to start early or finish late.
Reading the abbreviations literally will mislead you
MST strictly means one fixed offset, but almost nobody uses it that way. People write it to mean the time in Denver, which shifts if that city observes daylight saving — and it does. This page follows the common usage rather than the strict one, because the strict reading gives an answer that is wrong for a good part of the year.
Arizona sits in this zone but does not change its clocks, so for eight months of the year Phoenix matches Los Angeles rather than Denver. It is the most common source of a missed call in North American scheduling. GMT and UK time are the same thing only in winter. From late March to late October London runs on British Summer Time, an hour ahead of GMT, so a meeting booked as 'GMT' with someone in London is an hour out for most of the year.
Scheduling something recurring
For a one-off, the converter above is the whole job. For a standing meeting across zones it is worth putting the invitation in a calendar that stores the zone rather than the time — then the changeover is handled for you and nobody has to remember. If you are trying to find a slot across more than two places at once, the meeting planner shows a whole day at a glance instead.