Travelling from most locations, it is best to book your flight to Kolkata during the month of September for the best deal, although there are other times of the year which offer great deals as well.
In general, most flyers find the cheapest time to book a flight to Kolkata is about 60 days prior.
In general, booking your departure to Kolkata for a Wednesday represents the best deal on airfare. Try to avoid a Saturday departure to stay away from the highest prices.
Typically, cheap prices to Kolkata are most often found for afternoon flights. Cheap prices are less likely for noon flights.