What is the time difference between GMT and UTC?

Coordinated Universal Time (UTC) is 1 hour behind Greenwich Mean Time (GMT). GMT uses a UTC offset of UTC+1, while UTC uses UTC. For example, when it's 9:00 AM in GMT, it's 8:00 AM in UTC. Note that this difference may shift by one hour during daylight saving time transitions if GMT observes DST. Use the conversion table above to see the exact time for each hour of the day.

How do I convert GMT to UTC?

To convert GMT to UTC, subtract 1 hour from the GMT time. For example, 9:00 AM GMT is 8:00 AM UTC, and 5:00 PM GMT is 4:00 PM UTC. 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 UTC when it's noon in GMT?

When it's 12:00 PM (noon) in GMT, it's 11:00 AM in UTC. This is because UTC is 1 hour behind GMT. Similarly, when it's 6:00 PM in GMT, it's 5:00 PM in UTC. 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 UTC from GMT?

UTC is 1 hour behind GMT. This means when it's 9:00 AM in GMT, it's 8:00 AM in UTC, and when it's midnight in GMT, it's 11:00 PM in UTC. 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 UTC ahead or behind GMT?

UTC is behind GMT by 1 hour. Clocks in UTC show an earlier time than GMT, meaning the day starts later in UTC relative to GMT. For example, when it's noon in GMT, it's still 11:00 AM in UTC. 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 UTC conversions.

Does UTC observe daylight saving time?

No, Coordinated Universal Time does not observe daylight saving time. The UTC offset of UTC remains the same year-round, which simplifies time conversions. Regions using UTC keep their clocks unchanged regardless of the season.

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

The best time for a call between GMT and UTC is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in UTC during their work day, call between 10:00 AM and 6:00 PM your GMT time. Avoid calling too early or late, as the 1 hour 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 UTC 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 UTC ever have the same time?

No, GMT and UTC never show the same time because their base UTC offsets are different. However, because GMT observes daylight saving time and UTC does not, the time difference between them changes by one hour during DST transitions. This means the gap narrows or widens depending on the season, but the two clocks never align. Always verify the current offset around DST transition dates to avoid scheduling errors.

GMT to UTC Converter

Convert Greenwich Mean Time to Coordinated Universal 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).

View all DST changes

Timezone Details

Greenwich Mean Time

6:16 AM

Monday, October 19, 2026

BST (UTC+01:00)

UTC

5:16 AM

Monday, October 19, 2026

UTC (UTC+00:00)

Difference: -1 hour

BST DST: Yes (BST)

24-Hour Overview

BST — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

UTC — 24-hour overview

11p11p

12a

2a2a

5a5a

8a8a

10a

11a11a

12p

2p2p

5p5p

8p8p

10p

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

UTC 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

More Tools

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

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

Greenwich Mean Time on Wikipedia Coordinated Universal Time on Wikipedia IANA Time Zone Database