Compare GMT vs MST
See the 7-hour difference between Greenwich Mean Time and Mountain Standard Time, check DST impacts, and find the best meeting times.
GMT to MST Difference
Greenwich Mean Time is 7 hours ahead of Mountain Standard Time. View the current offset, overlapping hours, and side-by-side comparison tables.
DST Changes and Effects
MST stays at UTC-7, but many Mountain Time locations switch to daylight saving time as MDT (UTC-6). The page tracks DST changes automatically using the IANA timezone database.
Best Meeting Time Finder
Use the visual hour grid to spot suitable meeting windows between GMT and MST. Export selected times with ICS download or add them to Google Calendar and Gmail.
How to Find the Time Difference Between GMT and MST
Open the GMT vs MST converter: Visit https://www.xconvert.com/time-converter/gmt-vs-mst to load a comparison grid with Greenwich Mean Time (GMT) and Mountain Standard Time (MST) already in view. This page is useful when you need to schedule a call between the United Kingdom and teams in the western United States, Canada, or Mexico, especially when a 7-hour gap affects whether a meeting lands in the workday or before dawn.
Add relevant comparison cities: Click + Add City and search for cities that matter to your schedule, such as London for UK business hours, Denver or Phoenix for Mountain Time operations, and New York if you also need to coordinate with East Coast stakeholders. This is especially helpful for companies handling customer support, software handoffs, or logistics across North America and the UK, where one meeting may need to work for multiple offices.
Drag to select a meeting window: Click Select to enter selection mode, then drag across the timeline to highlight a range in purple; you can move the whole block by dragging the center or fine-tune it with the left and right handles. For example, selecting 9:00 to 12:00 GMT shows the corresponding 2:00 to 5:00 MST, which immediately tells you that a late-morning slot in Greenwich Mean Time becomes a very early morning window in Mountain Standard Time and may only suit teams starting work early.
Export and share the chosen time: Once a range is selected, use the export options for ICS download, Google Calendar, Gmail, Copy to clipboard, or Share link. This is practical when you want to send a confirmed cross-border meeting to a distributed team so each person sees the event in local time without manually converting GMT to MST again.
GMT vs MST Offset Explained
Greenwich Mean Time (GMT) is UTC+0, and Mountain Standard Time (MST) is UTC-7. MST is 7 hours behind GMT, and equivalently, GMT is 7 hours ahead of MST. In practical scheduling terms, when it is 9:00 GMT, it is 2:00 MST, and when it is 18:00 GMT, it is 11:00 MST.
This gap matters most when planning business calls across Europe and North America. A standard UK morning often overlaps with very early hours in Mountain Standard Time, so teams in sectors such as software development, customer service, and international operations often prefer late GMT afternoons to reach MST offices during their normal workday. The examples are straightforward: 12:00 GMT = 5:00 MST and 15:00 GMT = 8:00 MST, making early GMT afternoon one of the more workable periods for same-day collaboration.
Seasonal time changes can affect whether you should use these abbreviations. GMT is a standard-time abbreviation, and its daylight saving counterpart is BST. MST is also a standard-time abbreviation, and its daylight saving counterpart is MDT. That means GMT vs MST is the correct comparison when both locations are on their standard-time designations, while seasonal scheduling may require extra attention if a region is observing BST or MDT instead.
GMT is used across countries including the United Kingdom, Ireland, Iceland, Ghana, Senegal, Sierra Leone, Liberia, Mali, Mauritania, Guinea, Guinea-Bissau, Gambia, Togo, Burkina Faso, Sao Tome and Principe, Saint Helena, Guernsey, Jersey, Isle of Man, and Ivory Coast. MST is used in parts of Canada, Mexico, and the United States, so this comparison is common for transatlantic meetings, travel coordination, and support coverage spanning Europe, Africa, and western North America.
Frequently Asked Questions
What is the time difference between GMT and MST?
The difference between Greenwich Mean Time and Mountain Standard Time is 7 hours. MST is 7 hours behind GMT, which means a time that feels like mid-morning in GMT can still be very early in MST. For example, 9:00 GMT = 2:00 MST.
Is GMT ahead of MST or behind it?
GMT is 7 hours ahead of MST. This means the day starts earlier on the GMT clock, so if a UK-based team proposes a morning meeting, colleagues in Mountain Standard Time may see it fall before or near the start of their workday. A clear example is 15:00 GMT = 8:00 MST.
How do I convert GMT to MST quickly?
A fast way to convert is to use the fixed relationship that MST is 7 hours behind GMT. On the visual grid, you can drag over a GMT time block and immediately see the aligned MST hours below it, which is useful for picking a realistic overlap for meetings, webinars, or support shifts. Common reference points include 12:00 GMT = 5:00 MST and 18:00 GMT = 11:00 MST.
What is 9 AM GMT in MST?
9:00 GMT = 2:00 MST. This is an important example for teams trying to schedule a “morning” meeting from a GMT-based office, because it lands in the middle of the night or very early morning for people working on Mountain Standard Time schedules. In most business contexts, that makes 9 AM GMT too early for a same-day live meeting with MST participants.
What is noon GMT in MST?
12:00 GMT = 5:00 MST. Noon in Greenwich Mean Time still falls very early in Mountain Standard Time, so it may work for early-shift teams, transport operations, or global support desks, but it is often too early for a standard office meeting. If you need broad attendance, later GMT times usually create a better overlap.
What is 3 PM GMT in MST?
15:00 GMT = 8:00 MST. This is often closer to a practical overlap because it reaches the start of the workday in Mountain Standard Time while still staying within the afternoon in GMT. For cross-border project updates, sales calls, or operations check-ins, this kind of timing is usually easier than a GMT morning slot.
Does GMT vs MST change during daylight saving time?
The abbreviations themselves represent standard time: GMT for Greenwich Mean Time and MST for Mountain Standard Time. Their daylight saving counterparts are BST for GMT regions that switch seasonally and MDT for MST regions that observe daylight saving time. Because of that, you should pay attention to whether a location is currently using the standard-time abbreviation or the daylight-time abbreviation before setting recurring meetings.
Which countries use GMT and which countries use MST?
GMT is used in countries and territories including the United Kingdom, Ireland, Iceland, Ghana, Senegal, Sierra Leone, Liberia, Mali, Mauritania, Guinea, Guinea-Bissau, Gambia, Togo, Burkina Faso, Sao Tome and Principe, Saint Helena, Guernsey, Jersey, Isle of Man, and Ivory Coast. MST is used in parts of Canada, Mexico, and the United States. This makes GMT vs MST a common comparison for international business, travel planning, and distributed team scheduling across the Atlantic and North America.