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BlogHow it works

IST to CST Converter

Pick a date and an India time to see the matching time in Chicago, Dallas or Houston. The converter knows when the US Central zone is on CST and when it is on CDT.

India Standard Time

ISTIndia Standard Time

CSTCentral Time

––:––

What is the time difference between IST and CST?

India is 11 h 30 min ahead of US Central Standard Time and 10 h 30 min ahead of Central Daylight Time. Subtract that gap from an India time to get the time in Chicago.

IST
UTC+5:30, all year
CST
UTC−6, winter
CDT
UTC−5, summer

IST to CST time table

IST timeIST · CSTIST · CDT
12:00 AM12:30 PM−1 previous day1:30 PM−1 previous day
1:00 AM1:30 PM−1 previous day2:30 PM−1 previous day
2:00 AM2:30 PM−1 previous day3:30 PM−1 previous day
3:00 AM3:30 PM−1 previous day4:30 PM−1 previous day
4:00 AM4:30 PM−1 previous day5:30 PM−1 previous day
5:00 AM5:30 PM−1 previous day6:30 PM−1 previous day
6:00 AM6:30 PM−1 previous day7:30 PM−1 previous day
7:00 AM7:30 PM−1 previous day8:30 PM−1 previous day
8:00 AM8:30 PM−1 previous day9:30 PM−1 previous day
9:00 AM9:30 PM−1 previous day10:30 PM−1 previous day
10:00 AM10:30 PM−1 previous day11:30 PM−1 previous day
11:00 AM11:30 PM−1 previous day12:30 AM
12:00 PM12:30 AM1:30 AM
1:00 PM1:30 AM2:30 AM
2:00 PM2:30 AM3:30 AM
3:00 PM3:30 AM4:30 AM
4:00 PM4:30 AM5:30 AM
5:00 PM5:30 AM6:30 AM
6:00 PM6:30 AM7:30 AM
7:00 PM7:30 AM8:30 AM
8:00 PM8:30 AM9:30 AM
9:00 PM9:30 AM10:30 AM
10:00 PM10:30 AM11:30 AM
11:00 PM11:30 AM12:30 PM
Each India hour with the Central time in both seasons. +1 or −1 marks a time on the next or previous calendar day; India's 9:00 AM to 5:00 PM rows are in full color.

Why the gap changes twice a year

India runs on a single time zone, UTC+5:30, and does not use daylight saving time. The United States does: under the Energy Policy Act of 2005, clocks in most states move forward at 2:00 AM on the second Sunday in March and back at 2:00 AM on the first Sunday in November. The US Department of Transportation oversees time zones and these dates.

So the difference is 11 hours 30 minutes for about four months of the year and 10 hours 30 minutes for the other eight. The list below gives the exact stretches, worked out from the time zone data your browser also uses.

  1. Jan 1, 2026 – Mar 8, 2026IST UTC+5:30 · CST UTC−6Difference: −11:30 h
  2. Mar 8, 2026 – Nov 1, 2026IST UTC+5:30 · CDT UTC−5Difference: −10:30 h
  3. Nov 1, 2026 – Mar 14, 2027IST UTC+5:30 · CST UTC−6Difference: −11:30 h
  4. Mar 14, 2027 – Nov 7, 2027IST UTC+5:30 · CDT UTC−5Difference: −10:30 h
  5. Nov 7, 2027 – Jan 1, 2028IST UTC+5:30 · CST UTC−6Difference: −11:30 h

Offsets in 2026 – 2027, from the IANA time zone data in your browser's engine

Finding a meeting time

Office hours in India and the US Midwest barely touch. At 8:00 AM in Chicago it is already 7:30 PM in India during CST, or 6:30 PM during CDT, so an early US morning call is the usual compromise. The other option is a late US evening, which lands on the next morning in India: 9:00 PM in Chicago is 8:30 AM the next day in India in winter.

Because the date can change between the two places, write both the day and the time when you send an invitation, and add the zone to each. The live clocks for Delhi and Houston show both sides at a glance.

Do

  • Name the date in both places, for example Tue 9:00 AM CDT / Tue 7:30 PM IST.
  • Recheck recurring meetings in March and November, when the US clocks change.

Avoid

  • Writing CST in July. Chicago is on CDT then, and some people will read it literally.
  • Assuming the gap is a whole number of hours. India's half hour shifts every result by 30 minutes.

Which CST is this?

CST
Also called Central Standard Time · China Standard Time
The same three letters name two very different zones. On this page CST is US Central Time (UTC−6). China Standard Time is UTC+8 and only 2 h 30 min ahead of India, so if your contact is in Shanghai or Beijing, use a China time converter instead.

IST to CST questions

How many hours is IST ahead of CST?

IST is 11 hours 30 minutes ahead of Central Standard Time, which applies from early November to mid-March. From mid-March to early November Chicago is on CDT and the gap is 10 hours 30 minutes.

If it is 9:00 PM in India, what time is it in Chicago?

It is 9:30 AM the same day while Chicago is on CST, and 10:30 AM while it is on CDT.

Does India change its clocks for daylight saving time?

No. India keeps UTC+5:30 all year, so every change in the gap comes from the US side.

Is CST the same as CDT?

They are two phases of one zone. CST (UTC−6) is the winter time and CDT (UTC−5) is the summer time. Many people say CST all year, so check the date when a time matters.

Which US states use Central Time?

Illinois, Texas, Minnesota, Missouri and Louisiana are among the states that use it, and some states such as Tennessee and Kansas are split between Central and another zone.