Current time in IST (Asia/Kolkata)

What is Asia/Kolkata?

Asia/Kolkata records Indian Standard Time at UTC+5:30, based on the 82 degrees 30 minutes east meridian near Mirzapur. The half-hour offset comes from choosing a central meridian for a country with a wide east-west span rather than using a whole-hour political boundary. British India standardized the meridian in the early twentieth century, and independent India retained one national civil time. The Kolkata name reflects IANA convention and historical data, not a city-only rule. A named zone also protects old records from historical Kolkata, Mumbai, and wartime offsets that a simple IST label cannot explain.

Indian business hours vary widely by sector, but technology and shared-services teams often work late enough to overlap Europe and the US. A 9:30 or 10:00 a.m. start is common in many offices, with lunch around early afternoon and evening calls accepted in export-facing work. Banks, exchanges, and government offices keep more formal calendars. The half-hour offset is the operational trap: meeting tools must not round IST to a whole UTC hour. Release managers commonly choose late India evening for US overlap, but that can push routine work beyond normal local office expectations.

Use Asia/Kolkata for India-wide scheduling, software delivery, outsourcing, banking, payments, education, aviation, and national media. It covers Mumbai, Delhi, Bengaluru, Hyderabad, Chennai, Pune, and Kolkata, making it one of the highest-volume IANA identifiers for global product support and engineering calendars. Use it whenever India is a participant, because the half-hour offset is one of the most common global scheduling mistakes.