IST(India Standard Time)
India Standard Time (IST) is the single national time of India, five and a half hours ahead of UTC.
- UTC offset
- UTC+05:30
- Abbreviation
- IST
- Full name
- India Standard Time
- Regions
- India, Sri Lanka
- IANA zones
- Asia/Kolkata, Asia/Colombo
- Converter model
- Fixed offset.
What IST means
IST is the civil time of the whole of India, from Gujarat to Arunachal Pradesh, and Sri Lanka keeps the same offset.
- The half-hour offset means IST is never a whole number of hours from most other zones, so conversions can land on :30.
- India uses one offset across a very wide country, so sunrise in the north-east comes long before the working day begins.
Cities on this offset
These cities keep UTC+05:30 as their standard offset:
- Mumbai
- Delhi
- Bengaluru
- Kolkata
- Colombo
Other meanings of IST
IST is used for more than one time zone. This page describes India Standard Time; the other meanings have their own pages and their own offsets:
- IST — Irish Standard Time (UTC+01:00)
- IST — Israel Standard Time (UTC+02:00)
History
India Standard Time was established in 1906 on a meridian of 82°30′ east, near Mirzapur, and the half-hour offset that meridian produces has been kept ever since.