GMT to HST Converter
Understanding GMT and HST Time Zones
Greenwich Mean Time (GMT)
Greenwich Mean Time is observed in undefined and uses the offset UTC+0. Major cities in this time zone include London, Dublin, Lisbon. This time zone covers parts of Europe and/or Africa, home to major financial and cultural centers.
Hawaii Standard Time (HST)
Hawaii Standard Time operates at UTC-10, covering undefined. Key cities include Honolulu, Maui. The 10-hour backward offset from GMT means that when professionals in London start their workday at 9:00 AM, it is already 11:00 PM in Honolulu.
GMT is also commonly referred to as London time, UK time, British time, England time. HST is also known as Hawaii Time, Honolulu time, Hawaiian time. So if you are searching for London time to Hawaii Time, this is the same conversion as GMT to HST.
Complete GMT to HST Conversion Table
The table below shows every two-hour increment converted from Greenwich Mean Time to Hawaii Standard Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.
| GMT (Greenwich Mean Time) | HST (Hawaii Standard Time) |
|---|---|
| 12:00 AM (00:00) | 2:00 PM (14:00) (previous day) |
| 2:00 AM (02:00) | 4:00 PM (16:00) (previous day) |
| 4:00 AM (04:00) | 6:00 PM (18:00) (previous day) |
| 6:00 AM (06:00) | 8:00 PM (20:00) (previous day) |
| 8:00 AM (08:00) | 10:00 PM (22:00) (previous day) |
| 10:00 AM (10:00) | 12:00 AM (00:00) |
| 12:00 PM (12:00) | 2:00 AM (02:00) |
| 2:00 PM (14:00) | 4:00 AM (04:00) |
| 4:00 PM (16:00) | 6:00 AM (06:00) |
| 6:00 PM (18:00) | 8:00 AM (08:00) |
| 8:00 PM (20:00) | 10:00 AM (10:00) |
| 10:00 PM (22:00) | 12:00 PM (12:00) |
Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.
Scheduling Between GMT and HST
International conference calls between London, Dublin, Lisbon and Honolulu, Maui work best when scheduled during the overlap of both regions' business hours. Rotating meeting times monthly ensures fairness across time zones.
The large 10-hour gap between GMT and HST means that finding overlapping working hours requires compromise from at least one side. Consider adopting asynchronous workflows — recorded video updates, shared documents, and time-zone-aware project management tools — to supplement the limited real-time overlap.
Travel Between London and Honolulu
Booking hotels and transportation in Honolulu? Double-check whether listed check-in times are in HST (local) or your departure time zone. A common mistake is arriving 10 hours early or late due to unconverted times.
Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 10-hour shift between GMT and HST, plan for roughly one week of gradual adjustment for optimal performance.
Daylight Saving Time Considerations
When daylight saving time is in effect, the abbreviation changes (e.g., EST becomes EDT, CET becomes CEST). Our converter handles this automatically, but being aware of which version is active helps avoid confusion.
For the GMT to HST conversion specifically: GMT (UTC+0) observes DST, while HST (UTC-10) does not observe DST. This means the offset between them changes by one hour seasonally — the usual 10-hour gap becomes 9 or 11 hours during DST transitions.
Related Time Zone Conversions
References & Resources
Frequently Asked Questions
GMT (Greenwich Mean Time) is 10 hours ahead of HST (Hawaii Standard Time). GMT is UTC+0 and HST is UTC-10.
When it is 12:00 PM (noon) in GMT, it is 2:00 AM in HST.
The best overlap for business hours is approximately 11:00 PM to 7:00 AM HST, which corresponds to 9:00 AM to 5:00 PM in GMT. Given the large gap, consider alternating between early and late meeting times.
When daylight saving time is in effect, the abbreviation changes (e.g., EST becomes EDT, CET becomes CEST). Our converter handles this automatically, but being aware of which version is active helps avoid confusion.