IST to HAST Converter
HAST is 15.5 hours behind of IST.
IST
Thursday, October 22, 2026
India Standard Time · UTC+5:30
HAST
Thursday, October 22, 2026
Hawaii–Aleutian Standard Time · UTC−10
Convert IST to HAST
IST 17:39 = HAST 02:09
IST to HAST time chart, hour by hour
| IST | HAST |
|---|
| 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 HAST?
As abbreviations, HAST is always 15.5 hours behind of IST: IST is UTC+5:30 and HAST is UTC−10. To convert, subtract 15.5 hours.
Does the IST to HAST time difference change?
No. Hast is 15.5 hours behind of ist all year, because neither place changes its clocks.
Calling hours for IST and HAST
- When HAST 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 HAST time
How many hours ahead is HAST of IST?
HAST (UTC−10) is 15.5 hours behind of IST (UTC+5:30).
Does the time difference between IST and HAST change during the year?
No, it stays 15.5 hours behind all year because neither place changes its clocks.