What is the time difference between GMT and HST?

Hawaii Standard Time (HST) is 11 hours behind Greenwich Mean Time (GMT). GMT uses a UTC offset of UTC+1, while HST uses UTC-10. For example, when it's 9:00 AM in GMT, it's 10:00 PM in HST. 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 HST?

To convert GMT to HST, subtract 11 hours from the GMT time. For example, 9:00 AM GMT is 10:00 PM HST, and 5:00 PM GMT is 6:00 AM HST. 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 HST when it's noon in GMT?

When it's 12:00 PM (noon) in GMT, it's 1:00 AM in HST. This is because HST is 11 hours behind GMT. Similarly, when it's 6:00 PM in GMT, it's 7:00 AM in HST. 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 HST from GMT?

HST is 11 hours behind GMT. This means when it's 9:00 AM in GMT, it's 10:00 PM in HST, and when it's midnight in GMT, it's 1:00 PM in HST. 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 HST ahead or behind GMT?

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

Does HST observe daylight saving time?

No, Hawaii Standard Time does not observe daylight saving time. The UTC offset of UTC-10 remains the same year-round, making time conversions to HST more predictable. Countries and regions in this timezone keep their clocks unchanged regardless of the season.

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

The best time for a call between GMT and HST is during overlapping business hours (9 AM – 5 PM) in both timezones. To reach someone in HST during their work day, call between 8:00 PM and 4:00 AM your GMT time. Avoid calling too early or late, as the 11 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 HST 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 HST ever have the same time?

No, GMT and HST never show the same time because their base UTC offsets are different. However, because GMT observes daylight saving time and HST 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 HST Converter

Convert Greenwich Mean Time to Hawaii 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).

View all DST changes

Timezone Details

Greenwich Mean Time

4:19 PM

Thursday, October 22, 2026

BST (UTC+01:00)

Hawaii Standard Time

5:19 AM

Thursday, October 22, 2026

HST (UTC-10:00)

Difference: -11 hours

BST DST: Yes (BST)

HST DST: No

24-Hour Overview

BST — 24-hour overview

12a12a

3a3a

6a6a

9a9a

10a

11a

12p12p

3p3p

6p6p

9p9p

10p

11p

NightMorningBusinessEvening

HST — 24-hour overview

1p1p

4p4p

7p7p

10p10p

11p

12a

1a1a

4a4a

7a7a

10a10a

11a

12p

NightMorningBusinessEvening

Frequently Asked Questions

Related Conversions

HST 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

HST Cities

Honolulu

More Tools

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

Learn More

How Time Zones Work Understanding DST Timezone Abbreviations

External Resources

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