IST to HST Converter
HST is 15.5 hours behind of IST.
IST
Friday, October 2, 2026
India Standard Time · UTC+5:30
HST
Thursday, October 1, 2026
Hawaii Standard Time · UTC−10
Convert IST to HST
IST 04:42 = HST 13:12
IST to HST time chart, hour by hour
| IST | HST |
|---|
| 00:00 | 08:30 −1 day |
| 01:00 | 09:30 −1 day |
| 02:00 | 10:30 −1 day |
| 03:00 | 11:30 −1 day |
| 04:00 | 12:30 −1 day |
| 05:00 | 13:30 −1 day |
| 06:00 | 14:30 −1 day |
| 07:00 | 15:30 −1 day |
| 08:00 | 16:30 −1 day |
| 09:00 | 17:30 −1 day |
| 10:00 | 18:30 −1 day |
| 11:00 | 19:30 −1 day |
| 12:00 | 20:30 −1 day |
| 13:00 | 21:30 −1 day |
| 14:00 | 22:30 −1 day |
| 15:00 | 23:30 −1 day |
| 16:00 | 00:30 |
| 17:00 | 01:30 |
| 18:00 | 02:30 |
| 19:00 | 03:30 |
| 20:00 | 04:30 |
| 21:00 | 05:30 |
| 22:00 | 06:30 |
| 23:00 | 07:30 |
Highlighted rows fall within 09:00–18:00 in both places: 1 shared working hour.
How many hours is IST ahead of HST?
As abbreviations, HST is always 15.5 hours behind of IST: IST is UTC+5:30 and HST is UTC−10. To convert, subtract 15.5 hours.
Does the IST to HST time difference change?
No. Hst is 15.5 hours behind of ist all year, because neither place changes its clocks.
When IST and HST are both at work
- When HST is 15.5 hours behind of IST: no shared 09:00 to 17:00 hours; one side has to take the call outside office hours.
Frequently asked questions about IST and HST time
How many hours ahead is HST of IST?
HST (UTC−10) is 15.5 hours behind of IST (UTC+5:30).
Does the time difference between IST and HST change during the year?
No, it stays 15.5 hours behind all year because neither place changes its clocks.