IST to London

About India Standard Time

India keeps one clock, UTC+5:30, across a country spanning about 29 degrees of longitude — the sun rises nearly two hours earlier in Arunachal Pradesh than in Gujarat on the same clock. The half-hour offset means most conversions from India land on the half hour rather than the hour. Sri Lanka keeps the same time.

Cities on this clock: Mumbai, Delhi, Bangalore, Hyderabad, Chennai, Kolkata, Pune, Ahmedabad.

Watch out: IST is also Israel Standard Time (UTC+2) and Irish Standard Time (UTC+1). This page is the Indian one.

About United Kingdom Time

The United Kingdom is on GMT (UTC+0) for about five months and BST (UTC+1) for the rest, changing on the last Sunday in March and the last Sunday in October. Ireland keeps exactly the same clock, so every figure here applies to Dublin as well as London.

Cities on this clock: London, Lisbon, Dublin, Edinburgh, Manchester.

How the difference is worked out

The gap between India Standard Time and United Kingdom Time is not one number. The two zones change their clocks on different dates, so for part of the year the difference is 4 hours 30 minutes and for the rest it is something else — the table above lists each stretch of 2026 with the date it starts and which country's clocks moved.

With both zones on their own standard time — daylight saving not in force anywhere — United Kingdom Time is 5 hours 30 minutes behind India Standard Time. That figure never changes; everything else on this page follows from it plus whichever clocks have moved.

Every figure here comes from the IANA time zone database via your browser's own Intl engine, using the zone ids Asia/Kolkata and Europe/London. Nothing is looked up on a server and nothing about your visit is recorded.