HST to GMT Converter & Meeting Planner
Quick answer: 9:00 AM HST = 7:00 PM GMT (fixed -10:00 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Hawaii-Aleutian Standard Time (HST) and Greenwich Mean Time (GMT)? You need to account for the standard time difference. Greenwich Mean Time is normally 10 hours ahead of Hawaii-Aleutian Standard Time. Whether you are coordinating between teams in Honolulu and Hilo and London and Dublin, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM HST = 10:00 AM GMT. The full 24-hour HST to GMT table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM HST = 1:00 AM GMT (+1 day).
| HST Time | GMT Time |
|---|---|
| 12:00 AM (00:00) | 10:00 AM (10:00) |
| 1:00 AM (01:00) | 11:00 AM (11:00) |
| 2:00 AM (02:00) | 12:00 PM (12:00) |
| 3:00 AM (03:00) | 1:00 PM (13:00) |
| 4:00 AM (04:00) | 2:00 PM (14:00) |
| 5:00 AM (05:00) | 3:00 PM (15:00) |
| 6:00 AM (06:00) | 4:00 PM (16:00) |
| 7:00 AM (07:00) | 5:00 PM (17:00) |
| 8:00 AM (08:00) | 6:00 PM (18:00) |
| 9:00 AM (09:00) | 7:00 PM (19:00) |
| 10:00 AM (10:00) | 8:00 PM (20:00) |
| 11:00 AM (11:00) | 9:00 PM (21:00) |
| 12:00 PM (12:00) | 10:00 PM (22:00) |
| 1:00 PM (13:00) | 11:00 PM (23:00) |
| 2:00 PM (14:00) | 12:00 AM (00:00)+1 day |
| 3:00 PM (15:00) | 1:00 AM (01:00)+1 day |
| 4:00 PM (16:00) | 2:00 AM (02:00)+1 day |
| 5:00 PM (17:00) | 3:00 AM (03:00)+1 day |
| 6:00 PM (18:00) | 4:00 AM (04:00)+1 day |
| 7:00 PM (19:00) | 5:00 AM (05:00)+1 day |
| 8:00 PM (20:00) | 6:00 AM (06:00)+1 day |
| 9:00 PM (21:00) | 7:00 AM (07:00)+1 day |
| 10:00 PM (22:00) | 8:00 AM (08:00)+1 day |
| 11:00 PM (23:00) | 9:00 AM (09:00)+1 day |
Best time to call London from Honolulu
For most work calls, compare the normal business day in Honolulu (HST) with the business day in London (GMT). HST commonly covers Pacific Ocean, North America, while GMT is mainly associated with Europe, Africa.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
⚠️ There is no clean same-day business-hours overlap on 2026-07-05. A practical compromise is around 10:00 PM HST, which reaches 9:00 AM GMT near the start of their workday.
- DST Safety: HST or GMT may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- London Stock Exchange: 08:00-16:30 local time in London.
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Frequently Asked Questions
What is the time difference between HST and GMT?
During standard time, Greenwich Mean Time is 10 hours ahead of Hawaii-Aleutian Standard Time.
Does Hawaii observe Daylight Saving Time?
Hawaii does not observe Daylight Saving Time and has not done so since 1947, remaining fixed at UTC-10:00 year-round. At roughly 20° North latitude, Hawaii's daylight hours vary by only about 1.5 hours between the summer and winter solstices — far too little to justify the disruption of a seasonal clock change.
Why is it called Hawaii-Aleutian time?
The name combines two geographically distant US territories that share the same UTC-10:00 standard offset: the Hawaiian Islands in the central Pacific and the westernmost Aleutian Islands of Alaska, which extend past the 180° meridian into the Eastern Hemisphere. Despite sharing a base offset, they behave differently — Hawaii observes no DST, while the Aleutian communities such as Adak do advance to HDT (UTC-9) each summer.
What is the difference between GMT and BST?
GMT (Greenwich Mean Time) is the UK's standard winter offset at UTC+0, observed from the last Sunday in October through the last Sunday in March. BST (British Summer Time) is the daylight saving offset at UTC+1, applied each summer when clocks advance one hour.
Is GMT the same as UTC?
GMT and UTC share exactly the same numerical offset — both represent UTC+00:00 — but they are fundamentally different in nature. UTC is an atomic-clock-based international time standard used as the global reference, while GMT is a geographic time zone legally observed by specific countries including the United Kingdom and Ireland during winter months.