IST to CST Time Converter
Type a time in IST to see it in CST, with daylight saving handled for the date you pick. Every hour of the day is in the table below, and the meeting planner shows when both working days overlap.
In Chicago
9:30 pmCST
9:00 am IST on Wed 14 Jan 2026 is 9:30 pm CST the day before. Chicago is 11 h 30 min behind India.
- Date there
- Tuesday 13 January 2026
- Offsets
- IST UTC+5:30 · CST UTC−6
- Date used
- Example day: Wednesday 14 January 2026
How this works: Method, 3 sources, Checked against 1 worked example,
How this works
Method
Here IST means India Standard Time, UTC+5:30 all year; CST means Central Time, CST (UTC−6) in its winter and CDT (UTC−5) in its summer, as kept in Chicago. So CST is 11 h 30 min behind IST, and CDT is 10 h 30 min behind. Two 9-to-5 working days do not overlap at all, so one side has to start early or stay late. Full method
Sources
How it’s tested
One worked example for this page is checked by automated tests before every release: given the inputs, the tool must show the expected answer.
Changes
- 15 more conversion pages (IST to CST, BST to IST, SGT, GST, JST, MST and more); each conversion page shows all 24 hours with working hours shaded, and its best meeting times.
- The pickers find about a thousand more cities, states and countries (Seattle, Bangalore, Texas), and each conversion page names the next clock change on either side.
- The converter opens on the time now, live, with a Now choice beside the time, and the main converter starts from your own time zone.
- First published, with a world clock, pages for the time in 31 places and 15 common conversions such as PST to IST.
How to convert IST to CST
Here IST means India Standard Time, UTC+5:30 all year; CST means Central Time, CST (UTC−6) in its winter and CDT (UTC−5) in its summer, as kept in Chicago. So CST is 11 h 30 min behind IST, and CDT is 10 h 30 min behind. Two 9-to-5 working days do not overlap at all, so one side has to start early or stay late.
Teams in Bengaluru, Pune and Hyderabad that support clients in Chicago, Dallas, Houston or Minneapolis search IST to CST to find out when their US colleagues are at their desks. The answer is the Indian evening: the Central working day starts at 9:00 am, which is 8:30 pm in India in winter and 7:30 pm in summer, so a call slot between about 7:00 pm and 9:30 pm IST reaches the first hours of the Central morning.
The gap moves twice a year because of the US clocks, not India’s. From the second Sunday in March Chicago runs on CDT (UTC−5) and is 10 h 30 min behind India; from the first Sunday in November it is back on CST (UTC−6) and 11 h 30 min behind. A recurring call booked in Central time therefore appears an hour later on an Indian calendar from November to March. Some suppliers in China also write CST, meaning China Standard Time, which is 2 h 30 min ahead of India, so check which one an email means before you reply.
Rule of thumb: Subtract 11½ hours from Indian time (10½ while US Central is on daylight time) and step back a day if you cross midnight: 8:30 pm IST is 9:00 am CST or 10:00 am CDT.
CST = IST −11:30 · CDT = IST −10:30
- The US has changed its rules before: in 1974, during the energy crisis, the whole country went onto daylight time on 6 January, in the middle of winter. Source: IANA tz database, file northamerica (United States rules).
Meeting planner: best times for IST and CST
The IST and CST working days never overlap, so every meeting asks one side to start early or stay late. The shaded runs are the hours when both clocks are between 7 am and 9 pm; pick the end that suits whoever has the more flexible day, and swap it now and then.
January: IST and CST
- No hour is inside 9 to 5 on both clocks.
- Early or late for one side: 7:00 am to 8:30 am IST is 7:30 pm to 9:00 pm CST the day before (1 h 30 min); 6:30 pm to 9:00 pm IST is 7:00 am to 9:30 am CST (2 h 30 min).
July: IST and CDT
- No hour is inside 9 to 5 on both clocks.
- Early or late for one side: 7:00 am to 7:30 am IST is 8:30 pm to 9:00 pm CDT the day before (30 min); 5:30 pm to 9:00 pm IST is 7:00 am to 10:30 am CDT (3 h 30 min).
Both between 9 am and 5 pmBoth between 7 am and 9 pm
IST to CST time conversion table
Every hour of the IST day and the time in CST: the January column holds while the clocks are on IST and CST, the July column while they are on IST and CDT. The dates they switch are under the table.
| IST time | CST in January | CDT in July |
|---|---|---|
| 12:00 am | 12:30 pm (day before) | 1:30 pm (day before) |
| 1:00 am | 1:30 pm (day before) | 2:30 pm (day before) |
| 2:00 am | 2:30 pm (day before) | 3:30 pm (day before) |
| 3:00 am | 3:30 pm (day before) | 4:30 pm (day before) |
| 4:00 am | 4:30 pm (day before) | 5:30 pm (day before) |
| 5:00 am | 5:30 pm (day before) | 6:30 pm (day before) |
| 6:00 am | 6:30 pm (day before) | 7:30 pm (day before) |
| 7:00 am | 7:30 pm (day before) | 8:30 pm (day before) |
| 8:00 am | 8:30 pm (day before) | 9:30 pm (day before) |
| 9:00 am | 9:30 pm (day before) | 10:30 pm (day before) |
| 10:00 am | 10:30 pm (day before) | 11:30 pm (day before) |
| 11:00 am | 11:30 pm (day before) | 12:30 am |
| 12:00 pm | 12:30 am | 1:30 am |
| 1:00 pm | 1:30 am | 2:30 am |
| 2:00 pm | 2:30 am | 3:30 am |
| 3:00 pm | 3:30 am | 4:30 am |
| 4:00 pm | 4:30 am | 5:30 am |
| 5:00 pm | 5:30 am | 6:30 am |
| 6:00 pm | 6:30 am | 7:30 am |
| 7:00 pm | 7:30 am | 8:30 am |
| 8:00 pm | 8:30 am | 9:30 am |
| 9:00 pm | 9:30 am | 10:30 am |
| 10:00 pm | 10:30 am | 11:30 am |
| 11:00 pm | 11:30 am | 12:30 pm |
Shaded: 9 am to 5 pm on that clock. Where a row is shaded on both sides, both are at work.
When the IST–CST difference changes next
| Date | What happens | Then |
|---|---|---|
| Sun 1 Nov 2026 | Chicago falls back (CST) | CST is 11 h 30 min behind IST |
| Sun 14 Mar 2027 | Chicago springs forward (CDT) | CDT is 10 h 30 min behind IST |
Frequently Asked Questions
What is 9 am IST in CST?
In January, 9:00 am IST is 9:30 pm CST the day before. In July, 9:00 am IST is 10:30 pm CDT the day before.
What time is 7 pm IST in Chicago?
In winter, when Chicago is on CST, 7:00 pm in India is 7:30 am the same day in Chicago. From mid-March to early November, on CDT, it is 8:30 am. Dallas, Houston and the rest of US Central Time show the same.
Is IST to CST the same as IST to CDT?
They are the same clock at different times of year. CST (UTC−6) is used from early November to mid-March and CDT (UTC−5) the rest of the year. Many people write CST all year, so this page converts to whatever Chicago’s clock shows on your date.