Reading an India time from New York
India Standard Time is UTC+5:30 and never changes. New York is UTC-5 in winter and UTC-4 in summer. So the gap is 10 hours 30 minutes in January and 9 hours 30 minutes in July, with India ahead. A message that says 6:00 PM IST is 7:30 AM in New York in January and 8:30 AM in July.
That half hour trips people up. India is the only large zone most readers meet that sits on a half-hour offset, so mental arithmetic is easy to get wrong. Enter the IST time, or press Use now, and the page does the sums. Here IST means India, not Ireland or Israel, which use the same letters.
For an India-based team working with New York, the working days barely meet. A 9:00 to 17:00 day in India is 10:30 PM to 6:30 AM in New York in January, so a nine-to-five team shares no standard hours with its American counterpart. The hour-by-hour table makes this visible: the only workable slots are the end of the Indian evening and the start of the American morning.
Most conversions from India land on the previous calendar day in New York. A 9:00 AM IST start is 10:30 PM the night before in January, and the result says so. Press swap to go from Eastern to India.
Worked examples
Questions about this tool
Why is the gap 10.5 hours in winter and 9.5 hours in summer?
India does not use daylight saving, but New York does. When New York moves its clocks forward in spring, the gap shrinks by an hour.
Which IST times land in the American morning?
6:30 PM to 8:30 PM in India is 9:00 AM to 11:00 AM in New York in July. In January the same Eastern hours are 7:30 PM to 9:30 PM in India.
Does IST here mean Irish or Israel time?
No. On this page IST is India Standard Time, UTC+5:30.
Related tools
Where this comes from: IANA time zone database and the rules behind it ยท RFC 6557, how the time zone database is maintained