CDT/CST
Central Daylight Time
GMT -5
CST automatically adjusted to CDT time zone, that is in use
IST
India Standard Time
GMT +5:30
AEST
Australian Eastern Standard Time
GMT +10
AEST is NOT in use by many locations
AEDT (Australian Eastern Daylight Time) is used instead. Switch to AEDT time zone or select one of the cities Sydney, Melbourne, Gold Coast) for automatic timezone change.

Time Difference

Central Daylight Time is 10 hours and 30 minutes behind India Standard Time and 15 hours behind Australian Eastern Standard Time
8:00 pm20:00 in CDT is 6:30 am06:30 in IST and is 11:00 am11:00 in AEST

CST to IST call time
Best time for a conference call or a meeting is between 7am-9am in CST which corresponds to 6:30pm-8:30pm in IST
CST to AEST call time
Best time for a conference call or a meeting is between 5am-7am in CST which corresponds to 9pm-11pm in AEST

8:00 pm20:00 Central Daylight Time (CDT). Offset UTC -5:00 hours
6:30 am06:30 India Standard Time (IST). Offset UTC +5:30 hours
11:00 am11:00 Australian Eastern Standard Time (AEST). Offset UTC +10:00 hours

8:00 pm20:00 CDT / 6:30 am06:30 IST / 11:00 am11:00 AEST

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

Central Standard Time

Offset: CST is 6 hours behind Greenwich Mean Time (GMT) and is used in North America

Countries: It is used in following countries: Belize, Canada, Costa Rica, Guatemala, Honduras, Mexico, Nicaragua, El Salvador, United States

Principal Cities: The largest city in the CST timezone is Mexico City from Mexico with population about 12.294 million people. Other major cities in the area are Chicago, Houston, Iztapalapa, Ecatepec

French: HNC - Heure Normale du Centre

Spanish: CT - Tiempo Central Estándar, CT - Zona Centro

CST Time Zone Geo Map
CST timezone map

Daylight Saving: This is a standard time zone, however during summer some places switch clocks for one hour forward when daylight saving comes into effect and observe Central Daylight Time (CDT).

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Central Standard Time (CST) has ended on Sunday, March 9, 2025 at 2:00 am local time and clocks were set one hour forward to Sunday, March 9, 2025, 3:00 am local daylight time instead. Standard time ends annually the on second Sunday of March.

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

CST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • -06 - basic short
  • -0600 - basic
  • -06:00 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • -0600 - sign character (-) followed by a four digit time providing hours (06) and minutes (00) of the offset. Indicates six hour and zero minutes time differences to the west of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Sierra - Military abbreviation for CST
  • S - short form of 'Sierra'
IANA/Olson: Reflects CST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • America/Bahia_Banderas
  • America/Belize
  • America/Chicago
  • America/Chihuahua
  • America/Costa_Rica
  • America/El_Salvador
  • America/Guatemala
  • America/Indiana/Knox
  • America/Indiana/Tell_City
  • America/Knox_IN
  • America/Managua
  • America/Matamoros
  • America/Menominee
  • America/Merida
  • America/Mexico_City
  • America/Monterrey
  • America/North_Dakota/Beulah
  • America/North_Dakota/Center
  • America/North_Dakota/New_Salem
  • America/Ojinaga
  • America/Rainy_River
  • America/Rankin_Inlet
  • America/Regina
  • America/Resolute
  • America/Swift_Current
  • America/Tegucigalpa
  • America/Winnipeg
  • CST6CDT
  • Canada/Central
  • Canada/Saskatchewan
  • Mexico/General
  • US/Central
  • US/Indiana-Starke
CST Abbreviation: Several time zones share CST abbreviation and it could refer to these time zones
  • Central Standard Time - UTC -6
  • China Standard Time - UTC +8
  • Cuba Standard Time - UTC -5
  • Colombia Standard Time - UTC -5
Time zones with the GMT -6 offset:
  • CST - Central Standard Time
  • CT - Central Time
  • MDT - Mountain Daylight Time
  • EAST - Easter Island Standard Time
  • GALT - Galapagos Time
  • S - Sierra Time Zone

India Standard Time

Offset: IST is 5 hours and 30 minutes ahead Greenwich Mean Time (GMT) and is used in Asia

Countries: It is used in following countries: India

Principal Cities: The largest city in the IST timezone is Mumbai from India with population about 12.692 million people. Other major cities in the area are Delhi, Bangalore, Kolkata, Chennai

Daylight Saving: India Standard Time (IST) is not adjusted for daylight saving therefore IST remains the same through out the year. This means, unlike some time zones where the clock is set forward by one hour every summer and backward by one hour during winter to adjust for daylight saving, India Standard Time remains the same

IST Time Zone Geo Map
IST timezone map

IST representations, usage and related time zones

W3C/ISO-8601: International standard covering representation and exchange of dates and time-related data
  • +0530 - basic
  • +05:30 - extended
Email/RFC-2822: Internet Message Format Date Standard, typically used for timestamps in email headers
  • +0530 - sign character (+) followed by a four digit time providing hours (05) and minutes (30) of the offset. Indicates five hour and thirty minutes time differences to the east of the zero meridian.
IANA/Olson: Reflects IST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Asia/Calcutta
  • Asia/Kolkata
IST Abbreviation: Several time zones share IST abbreviation and it could refer to these time zones
  • India Standard Time - UTC +5:30
  • Irish Standard Time - UTC +1
  • Israel Standard Time - UTC +2
  • Iran Standard Time - UTC +3:30

Australian Eastern Standard Time

Offset: AEST is 10 hours 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 AEST timezone is Sydney from Australia with population about 4.627 million people. Other major cities in the area are Melbourne, Brisbane, Gold Coast, Canberra

AEST Time Zone Geo Map
AEST timezone map

Daylight Saving: This is a standard time zone, however during summer some places switch clocks for one hour forward when daylight saving comes into effect and observe Australian Eastern Daylight Time (AEDT).

Daylight saving time clock moves forward for one hour from 2am to 3amEnd: Australian Eastern Standard Time (AEST) has ended on Sunday, October 5, 2025 at 2:00 am local time and clocks were set one hour forward to Sunday, October 5, 2025, 3:00 am local daylight time instead. Standard time ends annually the on first Sunday of October.

Daylight saving time clock moves back for one hour from 3am to 2amStart: Australian Eastern Standard Time (AEST) starts on Sunday, April 5, 2026 at 3:00 am local time and clocks are set one hour back to Sunday, April 5, 2026, 2:00 am. Standard time starts annually the on first Sunday of April.

Australian Eastern Standard Time (AEST) is used in Queensland, Victoria, Tasmania, New South Wales (except Broken Hill), Australian Capital Territory and in folling major cities Brisbane, Sydney, Melbourne, Hobart, Canberra

Only part of Australia observe daylight saving. It is used in New South Wales, Victoria, South Australia, Tasmania, and the Australian Capital Territory. Daylight saving is not observed in Queensland, Western Australia or the Northern Territory.

AEST 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 ten hour and zero minutes time differences to the east of the zero meridian.
Military/NATO: Used by the U.S. military, Chinese military and others
  • Kilo - Military abbreviation for AEST
  • K - short form of 'Kilo'
IANA/Olson: Reflects AEST time zone boundaries defined by political bodies, primarily intended for use with computer programs and operating systems
  • Antarctica/Macquarie
  • Australia/ACT
  • Australia/Brisbane
  • Australia/Canberra
  • Australia/Currie
  • Australia/Hobart
  • Australia/Lindeman
  • Australia/Melbourne
  • Australia/NSW
  • Australia/Queensland
  • Australia/Sydney
  • Australia/Tasmania
  • Australia/Victoria
Time zones with the GMT +10 offset:
  • AEST - Australian Eastern Standard Time
  • CHUT - Chuuk Time
  • ChST - Chamorro Standard Time
  • K - Kilo Time Zone
  • KDT - Korea Daylight Time
  • PGT - Papua New Guinea Time
  • VLAT - Vladivostok Time
  • YAKST - Yakutsk Summer Time
  • YAPT - Yap Time