EST vs IST: How to Convert Time for US–India Meetings
Teams that work between the US East Coast and India deal with one of the trickiest time differences in business. The gap is not a whole number of hours, India never changes its clocks while the US does, and the two working days barely touch. This guide explains how EST and IST relate, how to convert between them correctly, and which meeting times tend to work best.
What EST and IST actually mean
IST, India Standard Time, is UTC+5:30 all year. India uses a single time zone for the whole country and does not observe daylight saving time, so its clocks never change.
EST, Eastern Standard Time, is UTC−5. It is only in force from the first Sunday in November to the second Sunday in March. The rest of the year the US East Coast uses EDT, Eastern Daylight Time, which is UTC−4. In everyday speech many people say "EST" all year, even when they mean EDT, which is a common source of one-hour mistakes. The safe term is "Eastern Time" (ET), and the safe zone name in software is America/New_York.
The time difference
When the US is on standard time (roughly November to March), India is 10 hours 30 minutes ahead of New York. When the US is on daylight time (roughly March to November), India is 9 hours 30 minutes ahead. Because India does not change its clocks, the whole shift comes from the US side.
Some examples in winter: 8:00 AM EST is 6:30 PM IST, 9:00 AM EST is 7:30 PM IST, and 9:00 PM EST is 7:30 AM IST the next day. In summer: 8:00 AM EDT is 5:30 PM IST, 9:00 AM EDT is 6:30 PM IST, and 9:00 PM EDT is 6:30 AM IST the next day.
Converting by hand
To convert Eastern time to India time, add 10 hours 30 minutes in winter or 9 hours 30 minutes in summer, and remember that the result often falls on the next calendar day. To convert India time to Eastern time, subtract the same amount. If 10:00 AM IST is your starting point, that is 11:30 PM EST or 12:30 AM EDT on the previous day.
The easiest way to avoid errors is to let software do the arithmetic using real time zone rules. A converter based on the IANA time zone database knows exactly when the US switches and will never apply the wrong offset.
Best meeting windows
With a standard 09:00–18:00 day on both sides, there is no hour when both offices are fully inside working time. The two practical options are an early US morning, which reaches India at the end of its working day, or a late US evening, which reaches India at the start of the next morning.
In summer, 8:00–9:00 AM EDT is 5:30–6:30 PM IST, which many Indian teams can accommodate. In winter the same US times land at 6:30–7:30 PM IST, so it often helps to start the US side a little earlier, around 7:30 AM EST. For evening slots, 9:00–10:00 PM ET reaches India between 6:30 and 8:30 AM depending on the season, which suits teams that prefer to start early.
For long-running projects, consider alternating between the morning and evening options so neither side always carries the inconvenience.
Watch the March and November changes
Recurring meetings booked in the US calendar will move by an hour for Indian attendees when the US changes its clocks in March and November. A call at 9:00 AM ET that sits at 7:30 PM IST in February will suddenly be at 6:30 PM IST in mid-March. Mention the change in your team channel the week before so nobody is caught out.
Quick tips
Write both times in the invite, for example "8:30 AM ET / 7:00 PM IST". Prefer "ET" over "EST" unless you specifically mean winter time. Check the date as well as the hour, since US evening calls fall on the next day in India. And keep recurring calls short, because the end of the Indian working day is usually the busiest time for handovers.