Reference offset
IST is commonly associated with UTC+5:30. The live clock shows the current regional offset separately.
Time-zone reference
India Standard Time
India Standard Time is the single national time standard used across India, with a half-hour offset from UTC.
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Keep the half hour in India Standard Time
India Standard Time is UTC+05:30. Asia/Kolkata is the IANA identifier used here even when you are scheduling for Delhi, Mumbai, or Bengaluru. The identifier names a representative rule set; it does not restrict the clock to one city.
IST is an ambiguous abbreviation internationally. It is also used in Irish and Israeli contexts with different meanings. Write India Standard Time or provide the +05:30 offset when the destination is unclear.
Conversion example
18:00 in India is 12:30 UTC. At a destination using UTC−05:00, the corresponding clock reads 07:30.
A common scheduling mistake
Treating +05:30 as 5.3 decimal hours is wrong: thirty minutes is half an hour, so the decimal value is 5.5.
Regional rules: IANA Time Zone Database Our calculation methods
What this abbreviation usually means
This page focuses on the Indian meaning of IST because the same abbreviation is used elsewhere for different zones.
IST conversion chart
Each hour of IST (UTC+5:30) converted to other common standard-time abbreviations. “+1” and “−1” mark the next or previous calendar day.
| IST | UTC | PST | EST | GMT | CET | JST |
|---|---|---|---|---|---|---|
| 00:00 | 18:30−1 | 10:30−1 | 13:30−1 | 18:30−1 | 19:30−1 | 03:30 |
| 01:00 | 19:30−1 | 11:30−1 | 14:30−1 | 19:30−1 | 20:30−1 | 04:30 |
| 02:00 | 20:30−1 | 12:30−1 | 15:30−1 | 20:30−1 | 21:30−1 | 05:30 |
| 03:00 | 21:30−1 | 13:30−1 | 16:30−1 | 21:30−1 | 22:30−1 | 06:30 |
| 04:00 | 22:30−1 | 14:30−1 | 17:30−1 | 22:30−1 | 23:30−1 | 07:30 |
| 05:00 | 23:30−1 | 15:30−1 | 18:30−1 | 23:30−1 | 00:30 | 08:30 |
| 06:00 | 00:30 | 16:30−1 | 19:30−1 | 00:30 | 01:30 | 09:30 |
| 07:00 | 01:30 | 17:30−1 | 20:30−1 | 01:30 | 02:30 | 10:30 |
| 08:00 | 02:30 | 18:30−1 | 21:30−1 | 02:30 | 03:30 | 11:30 |
| 09:00 | 03:30 | 19:30−1 | 22:30−1 | 03:30 | 04:30 | 12:30 |
| 10:00 | 04:30 | 20:30−1 | 23:30−1 | 04:30 | 05:30 | 13:30 |
| 11:00 | 05:30 | 21:30−1 | 00:30 | 05:30 | 06:30 | 14:30 |
| 12:00 | 06:30 | 22:30−1 | 01:30 | 06:30 | 07:30 | 15:30 |
| 13:00 | 07:30 | 23:30−1 | 02:30 | 07:30 | 08:30 | 16:30 |
| 14:00 | 08:30 | 00:30 | 03:30 | 08:30 | 09:30 | 17:30 |
| 15:00 | 09:30 | 01:30 | 04:30 | 09:30 | 10:30 | 18:30 |
| 16:00 | 10:30 | 02:30 | 05:30 | 10:30 | 11:30 | 19:30 |
| 17:00 | 11:30 | 03:30 | 06:30 | 11:30 | 12:30 | 20:30 |
| 18:00 | 12:30 | 04:30 | 07:30 | 12:30 | 13:30 | 21:30 |
| 19:00 | 13:30 | 05:30 | 08:30 | 13:30 | 14:30 | 22:30 |
| 20:00 | 14:30 | 06:30 | 09:30 | 14:30 | 15:30 | 23:30 |
| 21:00 | 15:30 | 07:30 | 10:30 | 15:30 | 16:30 | 00:30+1 |
| 22:00 | 16:30 | 08:30 | 11:30 | 16:30 | 17:30 | 01:30+1 |
| 23:00 | 17:30 | 09:30 | 12:30 | 17:30 | 18:30 | 02:30+1 |
Where IST is used
These cities on our world clock keep IST all year:
IST questions
What is IST in UTC?
IST (India Standard Time) is UTC+5:30, 5 hours 30 minutes ahead of UTC. To convert IST to UTC, subtract 5:30 hours: 12:00 IST is 06:30 UTC.
Does IST change for daylight saving time?
No. IST stays at UTC+5:30 all year. Its difference from zones that do observe daylight saving still changes when those regions move their clocks.
Which cities use IST?
Cities on our world clock that use IST include Mumbai, Delhi.
Compare IST with related zones
These are the abbreviations people most often compare against this reference.