What is the time difference between GMT and MST?

Mountain Standard Time (MST) is 6 hours behind Greenwich Mean Time (GMT). GMT uses a UTC offset of UTC, while MST uses UTC-6. For example, when it's 9:00 AM in GMT, it's 3:00 AM in MST. Note that this difference may shift by one hour during daylight saving time transitions if the two zones change on different dates. Use the conversion table above to see the exact time for each hour of the day.

How do I convert GMT to MST?

To convert GMT to MST, subtract 6 hours from the GMT time. For example, 9:00 AM GMT is 3:00 AM MST, and 5:00 PM GMT is 11:00 AM MST. Keep in mind that during daylight saving time transitions, the offset between these timezones may temporarily change by one hour. You can also use the interactive converter above for quick, accurate results.

What time is it in MST when it's noon in GMT?

When it's 12:00 PM (noon) in GMT, it's 6:00 AM in MST. This is because MST is 6 hours behind GMT. Similarly, when it's 6:00 PM in GMT, it's 12:00 PM in MST. During daylight saving time transitions, these times may shift by one hour, so always verify the current offset. The color-coded conversion table above shows every hour mapped between both timezones.

How many hours behind is MST from GMT?

MST is 6 hours behind GMT. This means when it's 9:00 AM in GMT, it's 3:00 AM in MST, and when it's midnight in GMT, it's 6:00 PM in MST. The exact difference can vary by one hour during daylight saving time transitions. The conversion table above provides a complete hour-by-hour mapping.

Is MST ahead or behind GMT?

MST is behind GMT by 6 hours. Clocks in MST show an earlier time than GMT, meaning the day starts later in MST relative to GMT. For example, when it's noon in GMT, it's still 6:00 AM in MST. This gap may change by one hour during DST transitions.

Does GMT observe daylight saving time?

Yes, Greenwich Mean Time observes daylight saving time. During DST, the abbreviation changes to BST and clocks move forward by one hour, typically in spring. Clocks then fall back in autumn, returning to standard GMT time. This means the UTC offset for GMT shifts between two values depending on the season. Check our DST change calendar for exact transition dates that may affect your GMT to MST conversions.

Does MST observe daylight saving time?

Yes, Mountain Standard Time observes daylight saving time. During DST, the abbreviation changes to MDT and clocks move forward by one hour, typically in spring. Clocks then fall back in autumn, returning to standard MST time. This means the UTC offset for MST shifts between two values depending on the season. Check our DST change calendar for exact transition dates that may affect your GMT to MST conversions.

What is the best time to call from GMT to MST?

The best time for a call between GMT and MST is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in MST during their work day, call between 3:00 PM and 11:00 PM your GMT time. Avoid calling too early or late, as the 6 hours difference means your evening could be their early morning. Check the color-coded conversion table above — green hours indicate business hours in both zones, making it easy to find the ideal time.

When does daylight saving time change in GMT?

Daylight saving time transitions vary by year and region. Greenwich Mean Time observes DST, which typically shifts clocks forward by one hour in spring ("spring forward") and back in fall ("fall back"). During these transition periods, the time difference between GMT and MST may temporarily change by one hour, which can cause confusion for scheduled meetings or calls. It's important to double-check your conversions around transition dates, especially if the two timezones switch on different dates. Check our DST change calendar for exact transition dates in the current year.

Do GMT and MST ever have the same time?

No, GMT and MST are always 6 hours apart and never display the same clock time simultaneously. Both timezones observe DST and typically transition around the same period, so the standard difference remains consistent throughout the year. The 6 hours offset is determined by their fixed positions relative to the Prime Meridian (UTC). You can always rely on this consistent difference when planning across these timezones.

GMT to MST Converter

Convert Greenwich Mean Time to Mountain Standard Time. See the hour-by-hour conversion table below.

Upcoming DST Change

UK Time (BST) will fall back on October 25. Clocks will shift by 1 hour (BST → GMT).

Mountain Time (MDT) will fall back on November 1. Clocks will shift by 1 hour (MDT → MST).

View all DST changes

Timezone Details

Greenwich Mean Time

4:03 AM

Sunday, October 25, 2026

GMT (UTC+00:00)

Mountain Standard Time

10:03 PM

Saturday, October 24, 2026

MDT (UTC-06:00)

Difference: -6 hours

GMT DST: Yes (BST)

MDT DST: Yes (MDT)

24-Hour Overview

GMT — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

MDT — 24-hour overview

5p5p

9p9p

10p

11p

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

MST to GMT EST to GMT GMT to EST PST to GMT GMT to PST GMT to IST IST to GMT GMT to CET CET to GMT

Cities in These Timezones

GMT Cities

London Manchester Edinburgh

MST Cities

Denver

More Tools

Compare GMT & MST Plan a Meeting (GMT & MST)See on Map

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

Greenwich Mean Time on Wikipedia Mountain Standard Time on Wikipedia IANA Time Zone Database