JST to IST Converter
Understanding JST and IST Time Zones
Japan Standard Time (JST)
Japan Standard Time is observed in undefined and uses the offset UTC+9. Major cities in this time zone include Tokyo, Osaka, Yokohama. This time zone serves a significant global region with important economic and cultural hubs.
India Standard Time (IST)
India Standard Time operates at UTC+5.5, covering undefined. Key cities include Mumbai, Delhi, Bangalore. The 3.5-hour backward offset from JST means that when professionals in Tokyo start their workday at 9:00 AM, it is already 5:30 AM in Mumbai.
JST is also commonly referred to as Japan time, Tokyo time, Japanese time. IST is also known as India time, Indian time, Mumbai time, Delhi time. So if you are searching for Japan time to India time, this is the same conversion as JST to IST.
Complete JST to IST Conversion Table
The table below shows every two-hour increment converted from Japan Standard Time to India Standard Time. Business hours (9 AM – 5 PM) are highlighted for easy scheduling reference.
| JST (Japan Standard Time) | IST (India Standard Time) |
|---|---|
| 12:00 AM (00:00) | 8:30 PM (20:30) (previous day) |
| 2:00 AM (02:00) | 10:30 PM (22:30) (previous day) |
| 4:00 AM (04:00) | 12:30 AM (00:30) |
| 6:00 AM (06:00) | 2:30 AM (02:30) |
| 8:00 AM (08:00) | 4:30 AM (04:30) |
| 10:00 AM (10:00) | 6:30 AM (06:30) |
| 12:00 PM (12:00) | 8:30 AM (08:30) |
| 2:00 PM (14:00) | 10:30 AM (10:30) |
| 4:00 PM (16:00) | 12:30 PM (12:30) |
| 6:00 PM (18:00) | 2:30 PM (14:30) |
| 8:00 PM (20:00) | 4:30 PM (16:30) |
| 10:00 PM (22:00) | 6:30 PM (18:30) |
Times shown in 12-hour and 24-hour format. Last updated 2026-03-09.
Scheduling Between JST and IST
When coordinating deliverables across JST and IST, set deadlines in the earlier time zone to avoid end-of-day confusion. A "5 PM deadline" should specify which zone to prevent missed deliveries due to the 3.5-hour offset.
The moderate 3.5-hour gap between JST and IST means that there is a partial overlap of business hours. Teams can typically find a 3–4 hour window that works for both sides without requiring anyone to work outside normal hours.
Travel Between Tokyo and Mumbai
Flight times between Tokyo and Mumbai often appear misleading because of the time zone shift. A departure at 10:00 AM JST arriving at 4.5:00 PM IST may look long, but remember to factor in the 3.5-hour offset.
Medical experts recommend allowing approximately one day of adjustment per hour of time difference. For the 3.5-hour shift between JST and IST, plan for about 3.5 days to fully acclimate.
Daylight Saving Time Considerations
Countries near the equator — including Singapore, most of Africa, and parts of South America — do not observe DST, making their offsets constant year-round. This simplifies scheduling compared to US or European zones.
For the JST to IST conversion specifically: JST (UTC+9) and IST (UTC+5.5) neither observes DST, so the 3.5-hour offset remains constant throughout the year. This makes scheduling reliable and predictable.
Related Time Zone Conversions
References & Resources
Frequently Asked Questions
JST (Japan Standard Time) is 3.5 hours ahead of IST (India Standard Time). JST is UTC+9 and IST is UTC+5.5.
When it is 12:00 PM (noon) in JST, it is 8:30 AM in IST.
The best overlap for business hours is approximately 5:00 AM to 1:00 PM IST, which corresponds to 9:00 AM to 5:00 PM in JST.
Countries near the equator — including Singapore, most of Africa, and parts of South America — do not observe DST, making their offsets constant year-round. This simplifies scheduling compared to US or European zones.