How many hours is PST behind IST?
As abbreviations, IST is always 13.5 hours ahead of PST: PST is UTC−8 and IST is UTC+5:30. To convert, add 13.5 hours.
Check which label you actually need: PST (Pacific Time is on PDT today). A time written with an abbreviation that is not in use is usually meant as the local time, so convert between the places instead: right now IST is 12.5 hours ahead of PST.
When the PST to IST time difference changes
For most of the year IST is 12.5 hours ahead of PST. From 1 November to 31 December 2026, IST is 13.5 hours ahead of PST instead, because the two places change their clocks on different dates. Meetings booked by the usual gap land an hour off in those weeks.
| Dates | IST vs PST | Length |
|---|---|---|
| 8 March 2026 to 31 October 2026 | 12.5 hours ahead | 238 days |
| 1 November 2026 to 31 December 2026 | 13.5 hours ahead | 61 days |
| 1 January 2027 to 13 March 2027 | 13.5 hours ahead | 72 days |
| 14 March 2027 to 6 November 2027 | 12.5 hours ahead | 238 days |
| 7 November 2027 to 31 December 2027 | 13.5 hours ahead | 55 days |
Calling hours for PST and IST
- When IST is 12.5 hours ahead of PST: no shared 09:00 to 17:00 hours; try 07:00 in PST (19:30 in IST).
- When IST is 13.5 hours ahead of PST: no shared 09:00 to 17:00 hours; try 07:00 in PST (20:30 in IST).