IST to COT Time Converter
COT is 10 hours and 30 minutes behind IST. IST is UTC+5:30, and COT is UTC-5:00.
Best Time to Call Between IST and COT
Standard 9-to-5 hours in these two zones never overlap, so someone has to take the call outside their working day. The most workable window is 6:00 PM to 10:00 PM IST, which is 7:30 AM to 11:30 AM COT.
both at work IST only COT only neither — hours along the strip are IST.
Common Times Converted
IST on the left, COT on the right.
IST to COT: Full 24-Hour Conversion Table
Shaded rows are working hours; the darker shade marks the hours when both zones are at work.
| IST | COT | Working hours |
|---|---|---|
| 12:00 AM | 1:30 PM prev day | COT only |
| 1:00 AM | 2:30 PM prev day | COT only |
| 2:00 AM | 3:30 PM prev day | COT only |
| 3:00 AM | 4:30 PM prev day | COT only |
| 4:00 AM | 5:30 PM prev day | — |
| 5:00 AM | 6:30 PM prev day | — |
| 6:00 AM | 7:30 PM prev day | — |
| 7:00 AM | 8:30 PM prev day | — |
| 8:00 AM | 9:30 PM prev day | — |
| 9:00 AM | 10:30 PM prev day | IST only |
| 10:00 AM | 11:30 PM prev day | IST only |
| 11:00 AM | 12:30 AM | IST only |
| 12:00 PM | 1:30 AM | IST only |
| 1:00 PM | 2:30 AM | IST only |
| 2:00 PM | 3:30 AM | IST only |
| 3:00 PM | 4:30 AM | IST only |
| 4:00 PM | 5:30 AM | IST only |
| 5:00 PM | 6:30 AM | — |
| 6:00 PM | 7:30 AM | — |
| 7:00 PM | 8:30 AM | — |
| 8:00 PM | 9:30 AM | COT only |
| 9:00 PM | 10:30 AM | COT only |
| 10:00 PM | 11:30 AM | COT only |
| 11:00 PM | 12:30 PM | COT only |
What IST and COT Actually Are
IST — India Standard Time
Mumbai, Delhi, Bengaluru, Chennai, Kolkata, Hyderabad — and Colombo. Standing at UTC+5:30 as written, and the region does not change its clocks, so that offset holds all year. IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.
India runs a single time zone across a country wide enough for two, which is why sunrise in the north-east can come nearly two hours before Mumbai's. Proposals for a second zone resurface regularly and have never been adopted.
COT — Colombia Time
Bogotá, Medellín, Cali, Barranquilla. Standing at UTC-5:00 as written, and the region does not change its clocks, so that offset holds all year.
Colombia briefly tried daylight saving during the energy crisis of 1992-93 and has not repeated it.
What This Means in Practice
Expect times on the half hour
IST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.
The date changes mid-working-day
For 2 of the eight hours in a normal IST working day, the equivalent COT time falls on a different calendar date. Anything scheduled in that stretch needs the date checked as well as the time, or a Tuesday call quietly becomes a Wednesday one at the other end.
A gap you can rely on
Neither region changes its clocks, so this difference holds every day of the year. A recurring meeting booked once stays correct — worth knowing, because most cross-border pairs cannot say that.
Nearly opposite sides of the clock
At 10 hours and 30 minutes apart, one side's morning is the other side's night. Handing work over at the end of a shift usually beats trying to get both parties in the same call.
Major Cities in Each Zone
Cities on IST
Cities on COT
Frequently Asked Questions
What is the time difference between IST and COT?
COT is 10 hours and 30 minutes behind IST.
What is 9:00 AM IST in COT?
9:00 AM IST is 10:30 PM the previous day COT.
What are the best hours to schedule a call between IST and COT?
Standard business hours in these two zones do not overlap at all, so one side has to work outside the 9-to-5. The most workable window is 6:00 PM to 10:00 PM IST, which is 7:30 AM to 11:30 AM COT.
Does the difference between IST and COT change during the year?
No. Neither region changes its clocks, so this gap is fixed all year round.
Does IST always mean India Standard Time?
IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.