BST to HDT Converter
Start by searching for a time zone, city, or town.
Add one or more places to compare local times, adjust the date, and share the result.
Quick answers
Selected conversion
12:00 pm12:00 GMT (UTC+0), Oct 29, 2026 = 3:00 am03:00 HDT (UTC-9), Oct 29, 2026
GMT is 9 hours ahead of HDT.
BST and HDT examples
These examples always use BST (UTC+1) and HDT (UTC-9). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.
BST is 10 hours ahead of HDT.
How the time difference changes
For most of the year, BST is 10 hours ahead of HDT. From Oct 25, 2026 to Mar 28, 2027, GMT is 9 hours ahead of HDT.
For most of the year, working hours of 9:00 am to 6:00 pm in BST correspond to 11:00 pm (previous day) to 8:00 am in HDT. At other times of the year, working hours of 9:00 am to 6:00 pm in GMT correspond to 12:00 am to 9:00 am in HDT.For most of the year, working hours of 09:00 to 18:00 in BST correspond to 23:00 (previous day) to 08:00 in HDT. At other times of the year, working hours of 09:00 to 18:00 in GMT correspond to 00:00 to 09:00 in HDT.
Compare BST time with HDT time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
Greenwich Mean Time is 9 hours ahead of Hawaii-Aleutian Daylight Time.
12:00 pm12:00 in GMT is 3:00 am03:00 in HDT
GMT to HDT call time
Best time for a conference call or a meeting is between 5:30pm-6:30pm17:30-18:30 in GMT which corresponds to 8:30am-9:30am08:30-09:30 in HDT. Their 9am–6pm09:00–18:00 working hours do not overlap; this is a suggested compromise.
12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours
3:00 am03:00 Hawaii-Aleutian Daylight Time (HDT). Offset UTC -9:00 hours
12:00 pm12:00 GMT / 3:00 am03:00 HDT
Choose an hour to update the converter. Day labels such as “next day” or “+1” are relative to the selected date in the first column. Use Up and Down arrow keys, Home or End to move between hours, then Enter or Space to select.
| GMT | HDT |
|---|---|
| 3:00pm previous day | |
| 4:00pm previous day | |
| 5:00pm previous day | |
| 6:00pm previous day | |
| 7:00pm previous day | |
| 8:00pm previous day | |
| 9:00pm previous day | |
| 10:00pm previous day | |
| 11:00pm previous day | |
| 12:00am | |
| 1:00am | |
| 2:00am | |
| 3:00am | |
| 4:00am | |
| 5:00am | |
| 6:00am | |
| 7:00am | |
| 8:00am | |
| 9:00am | |
| 10:00am | |
| 11:00am | |
| 12:00pm | |
| 1:00pm | |
| 2:00pm | |
| 15:00 previous day | |
| 16:00 previous day | |
| 17:00 previous day | |
| 18:00 previous day | |
| 19:00 previous day | |
| 20:00 previous day | |
| 21:00 previous day | |
| 22:00 previous day | |
| 23:00 previous day | |
| 00:00 | |
| 01:00 | |
| 02:00 | |
| 03:00 | |
| 04:00 | |
| 05:00 | |
| 06:00 | |
| 07:00 | |
| 08:00 | |
| 09:00 | |
| 10:00 | |
| 11:00 | |
| 12:00 | |
| 13:00 | |
| 14:00 |
British Summer Time
Offset: BST is 1 hour ahead of Greenwich Mean Time (GMT).
Countries using this time zone: Guernsey, Isle of Man, Jersey, United Kingdom
Principal Cities: The largest city in the BST time zone is London in the United Kingdom, with about 8.962 million people. Other major cities in this time zone include Birmingham, Glasgow, Manchester, Sheffield.
Greenwich Mean Time (GMT) originally referred to the mean solar time at the Royal Observatory in Greenwich, London. It is now often used to refer to Coordinated Universal Time (UTC) when this is viewed as a time zone, and in casual use the two are the same. In the military, GMT is known as Zulu time. Greenwich Mean Time was the same as Universal Time (UT), a standard astronomical concept used in many technical fields, until the introduction of UTC in 1972.
Current time in the United Kingdom: UK time now
Today the shaded areas are on UTC+0 (GMT).
BST representations, usage and related time zones
- +01 - basic short
- +0100 - basic
- +01:00 - extended
- +0100 - sign character (+) followed by a four digit time providing hours (01) and minutes (00) of the offset. Indicates an offset of one hour to the east of the zero meridian.
- Alpha - Military abbreviation for BST
- A - short form of 'Alpha'
- Europe/Belfast
- Europe/Guernsey
- Europe/Isle_of_Man
- Europe/Jersey
- Europe/London
- GB
- GB-Eire
- British Summer Time - UTC +1
- Bangladesh Standard Time - UTC +6
- Bougainville Standard Time - UTC +11
- BST - British Summer Time
- CET - Central European Time
- IST - Irish Standard Time
- WEST - Western European Summer Time
- A - Alpha Time Zone
- CET - Central European Time
- MEZ - Mitteleuropäische Zeit
- WAT - West Africa Time
- WST - Western Sahara Summer Time
- BMT - Biel Mean Time
Hawaii-Aleutian Daylight Time
Offset: HDT is 9 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: United States
Today all shaded areas are on HDT.
Daylight Saving: Hawaii-Aleutian Daylight Time (HDT) is a daylight saving/summer time zone. During winter, some places set clocks back one hour and observe Hawaii-Aleutian Standard Time (HAST).
Start: Hawaii-Aleutian Daylight Time (HDT) started on Sunday, March 8, 2026 at 2:00 am02:00 local time and clocks were set one hour forward to Sunday, March 8, 2026, 3:00 am03:00. Daylight saving starts annually on the second Sunday of March.
End: Hawaii-Aleutian Daylight Time (HDT) ends on Sunday, November 1, 2026 at 2:00 am02:00 local time and clocks are set one hour back to Sunday, November 1, 2026, 1:00 am01:00 local standard time instead. Daylight saving ends annually on the first Sunday of November.
See USA daylight saving time and upcoming clock changes worldwide.
HDT representations, usage and related time zones
- -09 - basic short
- -0900 - basic
- -09:00 - extended
- -0900 - sign character (-) followed by a four digit time providing hours (09) and minutes (00) of the offset. Indicates an offset of nine hours to the west of the zero meridian.
- Victor - Military abbreviation for HDT
- V - short form of 'Victor'
- America/Adak
- America/Atka
- US/Aleutian
- AKST - Alaska Standard Time
- AHDT - Alaska-Hawaii Daylight Time
- HADT - Hawaii-Aleutian Daylight Time
- GAMT - Gambier Time
- HDT - Hawaii-Aleutian Daylight Time
- V - Victor Time Zone