AST to CST Converter
Central Time is on daylight saving time: CDT (UTC−5) until Sun, Nov 1.
Mexico City and Saskatchewan stay on CST (UTC−6).
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
9:00 am09:00 ADT (UTC-3), Oct 24, 2026 = 7:00 am07:00 CDT (UTC-5), Oct 24, 2026
ADT is 2 hours ahead of CDT.
AST and CST (US winter time, UTC-6) examples
These examples always use AST (UTC-4) and CST (UTC-6). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.
AST is 2 hours ahead of CST.
CST is US Central winter time (early November to mid-March). The rest of the year Chicago uses CDT (UTC-5), one hour later. For Central Time that follows daylight saving time, use AST to CT. For daylight-time examples, use ADT to CDT.
How the time difference changes
For most of the year, ADT is 2 hours ahead of CDT. From Nov 1, 2026 to Mar 14, 2027, AST is 2 hours ahead of CST. Briefly around clock changes, ADT is 3 hours ahead of CST or AST is 1 hour ahead of CDT.
For most of the year, working hours of 9:00 am to 6:00 pm in ADT correspond to 7:00 am to 4:00 pm in CDT. At other times of the year, working hours of 9:00 am to 6:00 pm in AST correspond to 7:00 am to 4:00 pm in CST.For most of the year, working hours of 09:00 to 18:00 in ADT correspond to 07:00 to 16:00 in CDT. At other times of the year, working hours of 09:00 to 18:00 in AST correspond to 07:00 to 16:00 in CST.
Compare AST time with CST time, including current local time, UTC offsets, time difference, daylight saving changes, working hours, and shareable meeting times.
Time Difference
Atlantic Daylight Time is 2 hours ahead of Central Daylight Time.
9:00 am09:00 in ADT is 7:00 am07:00 in CDT
ADT to CDT call time
Best time for a conference call or a meeting is between 11am-6pm11:00-18:00 in ADT which corresponds to 9am-4pm09:00-16:00 in CDT
9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours
7:00 am07:00 Central Daylight Time (CDT). Offset UTC -5:00 hours
9:00 am09:00 ADT / 7:00 am07:00 CDT
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.
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Atlantic Standard Time
Offset: AST is 4 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: Anguilla, Antigua and Barbuda, Aruba, Barbados, Bermuda, British Virgin Islands, Canada, Caribbean Netherlands, Curaçao, Dominica, Dominican Republic, Greenland, Grenada, Guadeloupe, Martinique, Montserrat, Puerto Rico, Saint Barthélemy, Saint Kitts and Nevis, Saint Lucia, Saint Martin, Saint Vincent and the Grenadines, Sint Maarten, Trinidad and Tobago, US Virgin Islands
Principal Cities: The largest city in the AST time zone is Santo Domingo in the Dominican Republic, with about 2.202 million people. Other major cities in this time zone include Santiago de los Caballeros, Halifax, San Juan, San Pedro de Macorís.
French: HNA - Heure Normale de l'Atlantique
Spanish: AST - Tiempo Estándar del Atlántico
Today the lighter areas are on UTC−3 (ADT).
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).
End: Atlantic Standard Time (AST) ended 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 local daylight time instead. Standard time ends annually on the second Sunday of March.
Start: Atlantic Standard Time (AST) starts 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. Standard time starts annually on the first Sunday of November.
See Canada daylight saving time and upcoming clock changes worldwide.
AST representations, usage and related time zones
- -04 - basic short
- -0400 - basic
- -04:00 - extended
- -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.
- Quebec - Military abbreviation for AST
- Q - short form of 'Quebec'
- 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
- Atlantic Standard Time - UTC -4
- Arabia Standard Time - UTC +3
- AST - Atlantic Standard Time
- EDT - Eastern Daylight Time
- AMT - Amazon Time
- BOT - Bolivia Time
- CDT - Cuba Daylight Time
- CLT - Chile Standard Time
- GYT - Guyana Time
- HLV - Hora Legal de Venezuela
- Q - Quebec Time Zone
- VET - Venezuelan Standard Time
Central Standard Time
Offset: CST is 6 hours behind Greenwich Mean Time (GMT).
Countries using this time zone: Belize, Canada, Costa Rica, El Salvador, Guatemala, Honduras, Mexico, Nicaragua, United States
Principal Cities: The largest city in the CST time zone is Mexico City in Mexico, with about 12.294 million people. Other major cities in this time zone include Chicago, Houston, Puebla, Santiago de Querétaro.
French: HNC - Heure Normale du Centre
Spanish: CT - Tiempo Central Estándar, CT - Zona Centro
Today the lighter areas are on UTC−5 (Central Daylight Time).
Daylight Saving: This is a standard time zone. During summer, some places set clocks forward one hour for daylight saving time and observe Central Daylight Time (CDT).
End: Central Standard Time (CST) ended 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 local daylight time instead. Standard time ends annually on the second Sunday of March.
Start: Central Standard Time (CST) starts 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. Standard time starts annually on the first Sunday of November.
See USA daylight saving time and upcoming clock changes worldwide.
CST representations, usage and related time zones
- -06 - basic short
- -0600 - basic
- -06:00 - extended
- -0600 - sign character (-) followed by a four digit time providing hours (06) and minutes (00) of the offset. Indicates an offset of six hours to the west of the zero meridian.
- Sierra - Military abbreviation for CST
- S - short form of 'Sierra'
- 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
- Central Standard Time - UTC -6
- China Standard Time - UTC +8
- Cuba Standard Time - UTC -5
- CST - Central Standard Time
- CT - Central Time
- MDT - Mountain Daylight Time
- EAST - Easter Island Standard Time
- GALT - Galapagos Time
- S - Sierra Time Zone