Time ZonesAbout Indian Standard Time
India has one time zone, Indian Standard Time, five and a half hours ahead of UTC. It is based on the longitude 82.5° east, which runs near Prayagraj in Uttar Pradesh. India does not use daylight saving time, so IST never changes.
Why some differences have two values
Where the table shows two differences, the other city moves its clocks in summer. For part of the year it is one hour closer to India time, or one hour further. Each city page lists the exact dates.
A quick way to work it out
Subtract the offsets. Dubai is UTC+4 and India is UTC+5:30, so Dubai is 1 hour 30 minutes behind India. London in winter is UTC, so it is 5 hours 30 minutes behind. For a city not listed here, use the converter.
The list at a glance
Of the 30 cities here, 13 are ahead of India and 17 are behind or level. The closest clocks to India's are Colombo (the same time), Kathmandu (15 minutes ahead), Karachi (30 minutes behind). The farthest behind is Los Angeles, up to 13 hours 30 minutes, and the farthest ahead is Auckland, up to 7 hours 30 minutes. 11 of the cities move their clocks during the year, so their difference from India has two values: New York, Chicago, Denver, Los Angeles, Toronto, London, Paris, Berlin, Sydney, Melbourne, Auckland.
A rule of thumb for calls from India
For cities to the west, such as London, New York or Toronto, the Indian evening is their working day, so the hours after about 6 pm India time suit best. For cities to the east, such as Singapore, Tokyo or Sydney, the Indian morning is the overlap, and by the Indian afternoon their offices are closing. For the Gulf, almost the whole working day is shared. Each city page marks the exact hours in colour and works out the office hours both sides have in common.