In the graph below you see the time zone difference between India Standard Time and British Summer Time. Drag the bubble to adjust the time and to see the corresponding time in the other time zone.
India Standard Time is the time zone of India, including cities like New Delhi, Mumbai, Bangalore, Kolkata and Colombo. British Summer Time is the time zone of the United Kingdom when observing daylight saving time in the summer, with places like London, Dublin and Glasgow.
Usually it is preferable to schedule meetings after lunch for the person in IST and the morning for the person in BST.
India, Sri Lanka
Delhi, Colombo, Kolkata and Mumbai
This timezone does not observe daylight saving time so the time difference always stay the same. You however need to pay attention to if the other time zone is observing DST as this will make a difference.
IST can also refer to Irish Standard Time or Israeli Standard time, but most of the times it is India that is being referred to – just make sure to double check this before you send that calendar invite!
British Summer Time, or sometimes called British Standard Time, is the timezone of the United Kingdom in the summer months. It does not have a typical counterpart like most summer/winter pairs but is an exception to adjust for the dark winters in the UK!
United Kingdom only, including the Isle Of Man
All cities in the United Kingdom (England, Scotland, Wales and Northern Ireland), such as London, Manchester, Edinburgh, Cardiff and so on.
BST is the summer time equivalent of GMT. So for half the year the UK is on Greenwich Standard Time and the rest of the year they observe British Summer Time which is one hour ahead.
While GMT is observed in many places in addition to the UK BST is only observed in Britain (as the name suggests). Not even Ireland are on BST in the summer, instead they have their own time zone for this.