IST to GMT Time Converter

Common Times Converted

IST on the left, GMT on the right.

IST to GMT: Full 24-Hour Conversion Table

Shaded rows are working hours; the darker shade marks the hours when both zones are at work.

What IST and GMT Actually Are

IST — India Standard Time

Mumbai, Delhi, Bengaluru, Chennai, Kolkata, Hyderabad — and Colombo. Standing at UTC+5:30 as written, and the region does not change its clocks, so that offset holds all year. IST also stands for Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page covers the Indian one, which is by far the most searched.

India runs a single time zone across a country wide enough for two, which is why sunrise in the north-east can come nearly two hours before Mumbai's. Proposals for a second zone resurface regularly and have never been adopted.

GMT — Greenwich Mean Time

The UK and Ireland in winter, plus Iceland, Portugal and much of West Africa. Standing at UTC as written, and the region does change its clocks, so its live offset moves by an hour twice a year. The next change is on Sunday, October 25, 2026, to GMT. Often used loosely as a synonym for UTC. They differ by less than a second, so for scheduling they are interchangeable.

Britain ran an experiment from 1968 to 1971 on permanent UTC+1, abandoning GMT entirely. It was scrapped after complaints about dark winter mornings in Scotland.

What This Means in Practice

Expect times on the half hour

IST sits on a 30-minute offset rather than a whole hour, so a round number on one side is never a round number on the other. A 9:00 meeting becomes 30 minutes past the hour, which is exactly the detail calendar invitations get wrong when someone converts in their head.

This gap is not fixed

GMT changes its clocks and IST does not, so the difference between them moves by an hour twice a year. A recurring meeting set now will drift for one side from Sunday, October 25, 2026 unless someone resets it.

Major Cities in Each Zone

Cities on IST

Cities on GMT