How many hours is GMT ahead of MST?
As abbreviations, MST is always 7 hours behind of GMT: GMT is UTC+0 and MST is UTC−7. To convert, subtract 7 hours.
Check which label you actually need: MST (Mountain Time is on MDT today). A time written with an abbreviation that is not in use is usually meant as the local time, so convert between the places instead: right now MST is 6 hours behind of GMT.
When the GMT to MST time difference changes
For most of the year MST is 6 hours behind of GMT. From 1 November to 31 December 2026, MST is 7 hours behind of GMT instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
| Dates | MST vs GMT | Length |
|---|---|---|
| 8 March 2026 to 31 October 2026 | 6 hours behind | 238 days |
| 1 November 2026 to 31 December 2026 | 7 hours behind | 61 days |
| 1 January 2027 to 13 March 2027 | 7 hours behind | 72 days |
| 14 March 2027 to 6 November 2027 | 6 hours behind | 238 days |
| 7 November 2027 to 31 December 2027 | 7 hours behind | 55 days |
Calling hours for GMT and MST
- When MST is 6 hours behind of GMT: 2 shared office hours, 15:00 to 17:00 in GMT (09:00 to 11:00 in MST).
- When MST is 7 hours behind of GMT: 1 shared office hour, 16:00 to 17:00 in GMT (09:00 to 10:00 in MST).