IST to AST
On Oct 23, 2026, Atlantic Time is 8 hours 30 minutes behind India Standard Time: 9:00 AM IST is 12:30 AM ADT. The gap changes during the year because of daylight saving time; the dates are below.
AST vs IST over the next 12 months
| Period | AST is | Example |
|---|---|---|
| Oct 23, 2026 to Nov 1, 2026 | 8 hours 30 minutes behind | 9:00 AM IST = 12:30 AM ADT |
| Nov 1, 2026 to Mar 14, 2027 | 9 hours 30 minutes behind | 9:00 AM IST = 11:30 PM AST (previous day) |
| Mar 14, 2027 onwards | 8 hours 30 minutes behind | 9:00 AM IST = 12:30 AM ADT |
IST to AST conversion table
Every hour of a weekday around Oct 23, 2026, in both zones.
| India Standard Time | Atlantic Time |
|---|---|
| 12:00 AM | 3:30 PM (previous day) |
| 1:00 AM | 4:30 PM (previous day) |
| 2:00 AM | 5:30 PM (previous day) |
| 3:00 AM | 6:30 PM (previous day) |
| 4:00 AM | 7:30 PM (previous day) |
| 5:00 AM | 8:30 PM (previous day) |
| 6:00 AM | 9:30 PM (previous day) |
| 7:00 AM | 10:30 PM (previous day) |
| 8:00 AM | 11:30 PM (previous day) |
| 9:00 AM | 12:30 AM |
| 10:00 AM | 1:30 AM |
| 11:00 AM | 2:30 AM |
| 12:00 PM | 3:30 AM |
| 1:00 PM | 4:30 AM |
| 2:00 PM | 5:30 AM |
| 3:00 PM | 6:30 AM |
| 4:00 PM | 7:30 AM |
| 5:00 PM | 8:30 AM |
| 6:00 PM | 9:30 AM |
| 7:00 PM | 10:30 AM |
| 8:00 PM | 11:30 AM |
| 9:00 PM | 12:30 PM |
| 10:00 PM | 1:30 PM |
| 11:00 PM | 2:30 PM |
Best time for a meeting
There is no 9-to-5 overlap; within an 8 AM–8 PM day the zones overlap for 3 hours 30 minutes on a weekday: 4:30 PM–8:00 PM IST, which is 8:00 AM–11:30 AM ADT.
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Daylight saving time
Atlantic Time (AST/ADT)
- Nov 1, 2026: clocks go back 1 hour at 2:00 AM (UTC−3 → UTC−4)
- Mar 14, 2027: clocks go forward 1 hour at 2:00 AM (UTC−4 → UTC−3)
Where these clocks are used
- India Standard Time (IST): all of India: Mumbai, Delhi, Bengaluru, Chennai. IANA zone
Asia/Kolkata. - Atlantic Time (AST/ADT): Nova Scotia, New Brunswick, Prince Edward Island. IANA zone
America/Halifax.
Questions
What time is it in AST when it is 9 AM IST?
On Oct 23, 2026, 9:00 AM IST is 12:30 AM ADT. On other dates the answer can shift by an hour because of daylight saving time; the table of periods on this page gives each one.
How many hours behind IST is AST?
It depends on the date. Oct 23, 2026 to Nov 1, 2026: AST is 8 hours 30 minutes behind. Nov 1, 2026 to Mar 14, 2027: AST is 9 hours 30 minutes behind. Mar 14, 2027 onwards: AST is 8 hours 30 minutes behind.
Do IST and AST observe daylight saving time?
India Standard Time stays on UTC+5:30 all year. Atlantic Time switches to ADT (UTC−3) in summer and back to AST (UTC−4) in winter.
What is the best time for a meeting between IST and AST?
There is no 9-to-5 overlap; within an 8 AM–8 PM day the zones overlap for 3 hours 30 minutes on a weekday: 4:30 PM–8:00 PM IST, which is 8:00 AM–11:30 AM ADT.
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Related conversions
- AST to IST (reverse)
- IST to EST
- IST to CST
- IST to MST
- IST to PST
- IST to UTC
- IST to GMT
- IST to CET
- IST to SGT
- IST to JST
- IST to AEST
- IST to AKST
- All time zones
Computed from the IANA time zone database on Oct 23, 2026. Live clocks and the converter use your browser's copy of the same data.