There is no overlap between 09:00–18:00 working days in these two places.
How many hours is IST ahead of CDT?
As abbreviations, CDT is always 10.5 hours behind of IST: IST is UTC+5:30 and CDT is UTC−5. To convert, subtract 10.5 hours.
When the IST to CDT time difference changes
For most of the year CDT is 10.5 hours behind of IST. From 1 November to 31 December 2026, CDT is 11.5 hours behind of IST instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
Dates
CDT vs IST
Length
8 March 2026 to 31 October 2026
10.5 hours behind
238 days
1 November 2026 to 31 December 2026
11.5 hours behind
61 days
1 January 2027 to 13 March 2027
11.5 hours behind
72 days
14 March 2027 to 6 November 2027
10.5 hours behind
238 days
7 November 2027 to 31 December 2027
11.5 hours behind
55 days
Calling hours for IST and CDT
When CDT is 10.5 hours behind of IST: no shared 09:00 to 17:00 hours; try 18:00 in IST (07:30 in CDT).
When CDT is 11.5 hours behind of IST: no shared 09:00 to 17:00 hours; try 19:00 in IST (07:30 in CDT).
Frequently asked questions about IST and CDT time
How many hours ahead is CDT of IST?
CDT (UTC−5) is 10.5 hours behind of IST (UTC+5:30).
Does the time difference between IST and CDT change?
Yes. It is usually 10.5 hours behind, but changes when one side moves its clocks: 11.5 hours behind from 1 November to 31 December 2026; 11.5 hours behind from 1 January to 13 March 2027.