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HST to AST Converter

HST
Hawaii Standard Time
GMT -10
12am
3am
6am
9am
12pm
3pm
6pm
9pm
AST
Atlantic Standard Time
GMT -4
12am
3am
6am
9am
12pm
3pm
6pm
9pm

Quick answers

HST is 6 hours behind AST. HST uses GMT -10, and AST uses GMT -4 for this comparison.

For example, 2:00 am HST is 8:00 am AST. Use the converter above to adjust the date or time and create a shareable meeting link.

Best meeting overlap: 9am-11am HST, which is 3pm-5pm AST.

Compare HST time with AST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.

Time Difference

Hawaii Standard Time is 6 hours behind Atlantic Standard Time
2:00 am02:00 in HST is 8:00 am08:00 in AST

HST to AST call time
Best time for a conference call or a meeting is between 9am-11am in HST which corresponds to 3pm-5pm in AST

2:00 am02:00 Hawaii Standard Time (HST). Offset UTC -10:00 hours
8:00 am08:00 Atlantic Standard Time (AST). Offset UTC -4:00 hours

2:00 am02:00 HST / 8:00 am08:00 AST

HSTAST
12am (midnight)6am
1am7am
2am8am
3am9am
4am10am
5am11am
6am12pm (noon)
7am1pm
8am2pm
9am3pm
10am4pm
11am5pm
12pm (noon)6pm
1pm7pm
2pm8pm
3pm9pm
4pm10pm
5pm11pm
6pm12am (midnight)
7pm1am
8pm2am
9pm3am
10pm4am
11pm5am
00:0006:00
01:0007:00
02:0008:00
03:0009:00
04:0010:00
05:0011:00
06:0012:00
07:0013:00
08:0014:00
09:0015:00
10:0016:00
11:0017:00
12:0018:00
13:0019:00
14:0020:00
15:0021:00
16:0022:00
17:0023:00
18:0000:00
19:0001:00
20:0002:00
21:0003:00
22:0004:00
23:0005:00

Hawaii Standard Time

Offset: HST is 10 hours behind Greenwich Mean Time (GMT) and is used in Pacific

Countries using this time zone: United States

Principal Cities: The largest city in the HST time zone is Honolulu in the United States, with about 371,657 people. Other major cities in this time zone include Pearl City, Hilo, Kailua, Waipahu.

Daylight Saving: Clocks in Hawaii Standard Time (HST) do not change for daylight saving time, so HST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter.

HST Time Zone Geo Map
HST timezone map

HST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -10 - basic short
  • -1000 - basic
  • -10:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -1000 - sign character (-) followed by a four digit time providing hours (10) and minutes (00) of the offset. Indicates an offset of ten hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Whiskey - Military abbreviation for HST
  • W - short form of 'Whiskey'
IANA/Olson: Reflects HST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Adak
  • America/Atka
  • HST
  • Pacific/Honolulu
  • Pacific/Johnston
  • US/Aleutian
  • US/Hawaii
Time zones with the GMT -10 offset:
  • HAST - Hawaii-Aleutian Standard Time
  • CKT - Cook Island Time
  • HST - Hawaii Standard Time
  • TAHT - Tahiti Time
  • W - Whiskey Time Zone

Atlantic Standard Time

Offset: AST is 4 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries using this time zone: Antigua & Barbuda, Anguilla, Aruba, Barbados, St Barthelemy, Bermuda, Caribbean NL, Canada, Curaçao, Dominica, Dominican Republic, Grenada, Greenland, Guadeloupe, St Kitts & Nevis, St Lucia, St Martin (French), Martinique, Montserrat, Puerto Rico, St Maarten (Dutch), Trinidad & Tobago, St Vincent, Virgin Islands (UK), Virgin Islands (US)

Principal Cities: The largest city in the AST time zone is Santo Domingo in Dominican Republic, with about 2.202 million people. Other major cities in this time zone include Santiago de los Caballeros, Santo Domingo Oeste, San Juan, Halifax.

French: HNA - Heure Normale de l'Atlantique

Spanish: AST - Tiempo Estándar del Atlántico

AST Time Zone Geo Map
AST timezone map

Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Atlantic Daylight Time (ADT).

Daylight saving time clock moves back for one hour from 2am to 1amStart: Atlantic Standard Time (AST) started on Sunday, November 2, 2025 at 2:00 am local time and clocks were set one hour back to Sunday, November 2, 2025, 1:00 am. Standard time starts annually on the first Sunday of November.

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Atlantic Standard Time (AST) ends on Sunday, March 8, 2026 at 2:00 am local time and clocks are set one hour forward to Sunday, March 8, 2026, 3:00 am local daylight time instead. Standard time ends annually on the second Sunday of March.

AST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -04 - basic short
  • -0400 - basic
  • -04:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0400 - sign character (-) followed by a four digit time providing hours (04) and minutes (00) of the offset. Indicates an offset of four hours to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Quebec - Military abbreviation for AST
  • Q - short form of 'Quebec'
IANA/Olson: Reflects AST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Anguilla
  • America/Antigua
  • America/Aruba
  • America/Barbados
  • America/Blanc-Sablon
  • America/Curacao
  • America/Dominica
  • America/Glace_Bay
  • America/Goose_Bay
  • America/Grenada
  • America/Guadeloupe
  • America/Halifax
  • America/Kralendijk
  • America/Lower_Princes
  • America/Marigot
  • America/Martinique
  • America/Moncton
  • America/Montserrat
  • America/Port_of_Spain
  • America/Puerto_Rico
  • America/Santo_Domingo
  • America/St_Barthelemy
  • America/St_Kitts
  • America/St_Lucia
  • America/St_Thomas
  • America/St_Vincent
  • America/Thule
  • America/Tortola
  • America/Virgin
  • Atlantic/Bermuda
  • Canada/Atlantic
AST Abbreviation: Several time zones share AST abbreviation and it could refer to these time zones
  • Atlantic Standard Time - UTC -4
  • Arabia Standard Time - UTC +3
Time zones with the GMT -4 offset:
  • AST - Atlantic Standard Time
  • EDT - Eastern Daylight Time
  • AMT - Amazon Time
  • BOT - Bolivia Time
  • CDT - Cuba Daylight Time
  • CLT - Chile Standard Time
  • FKT - Falkland Island Time
  • GYT - Guyana Time
  • HLV - Hora Legal de Venezuela
  • PYT - Paraguay Time
  • Q - Quebec Time Zone
  • VET - Venezuelan Standard Time
EST to ISTGMT to ESTPST to ESTEST to GMTPST to GMT