IST to AST Converter

Updating current time…
IST
India Standard Time
UTC+5:30
12am
3am
6am
9am
12pm
3pm
6pm
9pm
ADT/AST
Atlantic Daylight Time
UTC−3
12am
3am
6am
9am
12pm
3pm
6pm
9pm
Atlantic Time is on daylight saving time: ADT (UTC−3) until Sun, Nov 1.
Use AST all year (UTC−4)

Quick answers

Selected conversion

5:30 pm17:30 IST (UTC+5:30), Oct 12, 2026 = 9:00 am09:00 ADT (UTC-3), Oct 12, 2026

IST is 8 hours and 30 minutes ahead of ADT.

IST and AST examples

These examples always use IST (UTC+5:30) and AST (UTC-4). They stay the same when you change the date or time above. The selected conversion may differ when daylight saving time applies.

IST is 9 hours and 30 minutes ahead of AST.

How the time difference changes

For most of the year, IST is 8 hours and 30 minutes ahead of ADT. From Nov 1, 2026 to Mar 14, 2027, IST is 9 hours and 30 minutes ahead of AST.

For most of the year, working hours of 9:00 am to 5:00 pm in IST correspond to 12:30 am to 8:30 am in ADT. At other times of the year, working hours of 9:00 am to 5:00 pm in IST correspond to 11:30 pm (previous day) to 7:30 am in AST.For most of the year, working hours of 09:00 to 17:00 in IST correspond to 00:30 to 08:30 in ADT. At other times of the year, working hours of 09:00 to 17:00 in IST correspond to 23:30 (previous day) to 07:30 in AST.

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

Time Difference

India Standard Time is 8 hours and 30 minutes ahead of Atlantic Daylight Time.
5:30 pm17:30 in IST is 9:00 am09:00 in ADT

IST to ADT call time
Best time for a conference call or a meeting is between 5pm-6pm17:00-18:00 in IST which corresponds to 8:30am-9:30am08:30-09:30 in ADT. Their 9am–5pm09:00–17:00 working hours do not overlap; this is a suggested compromise.

5:30 pm17:30 India Standard Time (IST). Offset UTC +5:30 hours
9:00 am09:00 Atlantic Daylight Time (ADT). Offset UTC -3:00 hours

5:30 pm17:30 IST / 9:00 am09:00 ADT

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.

Hourly time comparison
ISTADT
3:30pm previous day
4:30pm previous day
5:30pm previous day
6:30pm previous day
7:30pm previous day
8:30pm previous day
9:30pm previous day
10:30pm previous day
11:30pm previous day
12:30am
1:30am
2:30am
3:30am
4:30am
5:30am
6:30am
7:30am
8:30am
9:30am
10:30am
11:30am
12:30pm
1:30pm
2:30pm
15:30 previous day
16:30 previous day
17:30 previous day
18:30 previous day
19:30 previous day
20:30 previous day
21:30 previous day
22:30 previous day
23:30 previous day
00:30
01:30
02:30
03:30
04:30
05:30
06:30
07:30
08:30
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India Standard Time

Offset: IST is 5 hours and 30 minutes ahead of Greenwich Mean Time (GMT).

Countries using this time zone: India

Principal Cities: The largest city in the IST time zone is Mumbai in India, with about 12.692 million people. Other major cities in this time zone include Delhi, Bengaluru, Hyderabad, Ahmedabad.

Daylight Saving: Clocks in India Standard Time (IST) do not change for daylight saving time, so IST stays the same throughout the year. Other time zones may set clocks forward in summer and back in winter; see upcoming clock changes worldwide.

Map of the areas on India Standard Time (IST)
IST all year

Open the world time zone map© OpenStreetMap

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 an offset of five hours and thirty minutes 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

Atlantic Standard Time

Offset: AST is 4 hours behind Greenwich Mean Time (GMT).

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 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

Map of the areas on Atlantic Standard Time (AST)
AST all year AST part of the year

Today the lighter areas are on UTC−3 (ADT).

Open the world time zone map© OpenStreetMap

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).

123456789101112End: 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.

123456789101112Start: 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 upcoming clock changes worldwide.

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