ACST
Australian Central Standard Time
GMT +9:30
ACST is NOT in use by many locations
ACDT (Australian Central Daylight Time) is used instead. Switch to ACDT time zone or select one of the cities Adelaide, Darwin, Adelaide Hills for automatic timezone change.
GMT
Greenwich Mean Time
GMT +0

Time Difference

Australian Central Standard Time is 9 hours and 30 minutes ahead of Greenwich Mean Time
9:30 pm21:30 in ACST is 12:00 pm12:00 in GMT

ACST to GMT call time
Best time for a conference call or a meeting is between 5:30pm-7:30pm in ACST which corresponds to 8am-10am in GMT

9:30 pm21:30 Australian Central Standard Time (ACST). Offset UTC +9:30 hours
12:00 pm12:00 Greenwich Mean Time (GMT). Offset UTC 0:00 hours

9:30 pm21:30 ACST / 12:00 pm12:00 GMT

ACST GMT
12am (midnight) 2:30 pm
1am 3:30 pm
2am 4:30 pm
3am 5:30 pm
4am 6:30 pm
5am 7:30 pm
6am 8:30 pm
7am 9:30 pm
8am 10:30 pm
9am 11:30 pm
10am 12:30 am
11am 1:30 am
12pm (noon) 2:30 am
1pm 3:30 am
2pm 4:30 am
3pm 5:30 am
4pm 6:30 am
5pm 7:30 am
6pm 8:30 am
7pm 9:30 am
8pm 10:30 am
9pm 11:30 am
10pm 12:30 pm
11pm 1:30 pm
0:00 14:30
1:00 15:30
2:00 16:30
3:00 17:30
4:00 18:30
5:00 19:30
6:00 20:30
7:00 21:30
8:00 22:30
9:00 23:30
10:00 0:30
11:00 1:30
12:00 2:30
13:00 3:30
14:00 4:30
15:00 5:30
16:00 6:30
17:00 7:30
18:00 8:30
19:00 9:30
20:00 10:30
21:00 11:30
22:00 12:30
23:00 13:30

Australian Central Standard Time

Offset: ACST is 9 hours and 30 minutes ahead Greenwich Mean Time (GMT) and is used in Australia

Countries: It is used in following countries: Australia

Principal Cities: The largest city in the ACST timezone is Adelaide from Australia with population about 1.225 million people. Other major cities in the area are Darwin, Adelaide Hills, Alice Springs, Palmerston

Daylight Saving: This is a standard timezone, however during summer some places adjust time for one hour forward for daylight saving and observe Australian Central Daylight Time (ACDT).

End: ACST ends annually on the same date and time. and clocks were set one hour forward on Sunday, 03 October 2021, at 2:00 (2:00 am) local time.

Start: ACST starts annually on the same date and time. and clocks are set one hour back on Sunday, 03 April 2022, at 3:00 (3:00 am) local time.

ACST Time Zone Geo Map
ACST timezone map

ACST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +0930 - basic
  • +09:30 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0930 - sign character (+) followed by a four digit time providing hours (09) and minutes (30) of the offset. Indicates nine hour and thirty minutes time differences to the east of the zero meridian.
IANA/Olson: Reflects ACST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Australia/Adelaide
  • Australia/Broken_Hill
  • Australia/Darwin
  • Australia/North
  • Australia/South
  • Australia/Yancowinna

Greenwich Mean Time

Offset: GMT is 0 hours ahead Greenwich Mean Time (GMT) and is used in Europe

Countries: It is used in following countries: Burkina Faso, Côte d'Ivoire, Britain (UK), Guernsey, Ghana, Greenland, Gambia, Guinea, Guinea-Bissau, Ireland, Isle of Man, Iceland, Jersey, Liberia, Mali, Mauritania, St Helena, Sierra Leone, Senegal, Sao Tome & Principe, Togo

Principal Cities: The largest city in the GMT timezone is London from United Kingdom with population about 7.557 million people. Other major cities in the area are Abidjan, Dakar, Grand Dakar, Accra

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 for the most parts it is the same. In military GMT is known as Zulu time.Greenwich Mean Time was the same as Universal Time (UT), until the introduction of UTC in 1972 a standard astronomical concept used in many technical fields.

GMT Time Zone Geo Map
GMT timezone map

GMT representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • Z - is the zone designator for the zero UTC/GMT offset, also known as 'Zulu' time
  • +00 - basic short
  • +0000 - basic
  • +00:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0000 - sign character (+) followed by a four digit time providing hours (00) and minutes (00) of the offset. Indicates zero hour and zero minutes time differences of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Zulu - Military abbreviation for GMT
  • Z - short form of 'Zulu'
IANA/Olson: Reflects GMT time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Africa/Abidjan
  • Africa/Accra
  • Africa/Bamako
  • Africa/Banjul
  • Africa/Bissau
  • Africa/Conakry
  • Africa/Dakar
  • Africa/Freetown
  • Africa/Lome
  • Africa/Monrovia
  • Africa/Nouakchott
  • Africa/Ouagadougou
  • Africa/Sao_Tome
  • Africa/Timbuktu
  • America/Danmarkshavn
  • Atlantic/Reykjavik
  • Atlantic/St_Helena
  • Eire
  • Etc/GMT
  • Etc/GMT+0
  • Etc/GMT-0
  • Etc/GMT0
  • Etc/Greenwich
  • Europe/Belfast
  • Europe/Dublin
  • Europe/Guernsey
  • Europe/Isle_of_Man
  • Europe/Jersey
  • Europe/London
  • GB
  • GB-Eire
  • GMT
  • GMT+0
  • GMT-0
  • GMT0
  • Greenwich
  • Iceland
GMT Abbreviation: Several time zones share GMT abbreviation and it could refer to these time zones
  • Greenwich Mean Time - UTC +0
  • GMT+06:00 - UTC +6
  • GMT - UTC +1
  • GMT+04:00 - UTC +4
Time zones with the GMT +0 offset:
  • EGST - Eastern Greenland Summer Time
  • GMT - Greenwich Mean Time
  • WET - Western European Time
  • AZOST - Azores Summer Time
  • UTC - Universal Time Coordinated
  • WT - Western Sahara Standard Time
  • Z - Zulu Time Zone
  • AST - Azores Summer Time