IST to HST Converter & Meeting Planner
Quick answer: 9:00 AM IST = 5:30 PM HST (fixed +05:30 standard offset — not DST-adjusted). Use the interactive converter below for DST-aware local-time scheduling.
Planning a call or meeting between Indian Standard Time (IST) and Hawaii-Aleutian Standard Time (HST)? You need to account for the standard time difference. Hawaii-Aleutian Standard Time is normally 15.5 hours behind Indian Standard Time. Whether you are coordinating between teams in Mumbai and New Delhi and Honolulu and Hilo, our live tool has you covered. Use our interactive overlap studio below to find the perfect waking hours for both regions, taking into account any seasonal Daylight Saving Time (DST) changes.
24-Hour Conversion Table
Quick reference: 12:00 AM IST = 8:30 AM HST. The full 24-hour IST to HST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM IST = 11:30 PM HST (-1 day).
| IST Time | HST Time |
|---|---|
| 12:00 AM (00:00) | 8:30 AM (08:30)-1 day |
| 1:00 AM (01:00) | 9:30 AM (09:30)-1 day |
| 2:00 AM (02:00) | 10:30 AM (10:30)-1 day |
| 3:00 AM (03:00) | 11:30 AM (11:30)-1 day |
| 4:00 AM (04:00) | 12:30 PM (12:30)-1 day |
| 5:00 AM (05:00) | 1:30 PM (13:30)-1 day |
| 6:00 AM (06:00) | 2:30 PM (14:30)-1 day |
| 7:00 AM (07:00) | 3:30 PM (15:30)-1 day |
| 8:00 AM (08:00) | 4:30 PM (16:30)-1 day |
| 9:00 AM (09:00) | 5:30 PM (17:30)-1 day |
| 10:00 AM (10:00) | 6:30 PM (18:30)-1 day |
| 11:00 AM (11:00) | 7:30 PM (19:30)-1 day |
| 12:00 PM (12:00) | 8:30 PM (20:30)-1 day |
| 1:00 PM (13:00) | 9:30 PM (21:30)-1 day |
| 2:00 PM (14:00) | 10:30 PM (22:30)-1 day |
| 3:00 PM (15:00) | 11:30 PM (23:30)-1 day |
| 4:00 PM (16:00) | 12:30 AM (00:30) |
| 5:00 PM (17:00) | 1:30 AM (01:30) |
| 6:00 PM (18:00) | 2:30 AM (02:30) |
| 7:00 PM (19:00) | 3:30 AM (03:30) |
| 8:00 PM (20:00) | 4:30 AM (04:30) |
| 9:00 PM (21:00) | 5:30 AM (05:30) |
| 10:00 PM (22:00) | 6:30 AM (06:30) |
| 11:00 PM (23:00) | 7:30 AM (07:30) |
Best time to call Honolulu from Mumbai
For most work calls, compare the normal business day in Mumbai (IST) with the business day in Honolulu (HST). IST commonly covers South Asia, while HST is mainly associated with Pacific Ocean, North America.
⚠️ Note: 2026-07-05 is not a normal workday in one or both regions based on their configured calendar. The overlap below should be treated as a reference, not a guaranteed office-hours window.
⚠️ There is no clean same-day business-hours overlap on 2026-07-05. A practical compromise is around 12:30 AM IST, which reaches 9:00 AM HST near the start of their workday.
- DST Safety: IST or HST may shift during Daylight Saving Time. Always confirm the converted time for your specific date.
- Bombay Stock Exchange (BSE): 09:15-15:30 local time in Mumbai.
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Frequently Asked Questions
What is the time difference between IST and HST?
During standard time, Hawaii-Aleutian Standard Time is 15.5 hours behind Indian Standard Time.
Does India observe Daylight Saving Time (DST)?
India does not observe Daylight Saving Time and has not done so since 1945. IST remains fixed at UTC+5:30 every day of the year, meaning the offset between India and any DST-observing country shifts by one hour twice annually when those countries change their clocks.
Why does IST have a 30-minute offset?
India chose the 82.5° East meridian — which passes through Mirzapur in Uttar Pradesh — as its central reference longitude, as it bisects the subcontinent geographically. That meridian sits exactly 5 hours and 30 minutes ahead of the Prime Meridian in Greenwich, producing the UTC+5:30 offset that has defined IST since 1906.
Does Hawaii observe Daylight Saving Time?
Hawaii does not observe Daylight Saving Time and has not done so since 1947, remaining fixed at UTC-10:00 year-round. At roughly 20° North latitude, Hawaii's daylight hours vary by only about 1.5 hours between the summer and winter solstices — far too little to justify the disruption of a seasonal clock change.
Why is it called Hawaii-Aleutian time?
The name combines two geographically distant US territories that share the same UTC-10:00 standard offset: the Hawaiian Islands in the central Pacific and the westernmost Aleutian Islands of Alaska, which extend past the 180° meridian into the Eastern Hemisphere. Despite sharing a base offset, they behave differently — Hawaii observes no DST, while the Aleutian communities such as Adak do advance to HDT (UTC-9) each summer.