IST to JST Converter & Meeting Planner
Quick answer: 9:00 AM IST = 12:30 PM JST (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 Japan Standard Time (JST)? You need to account for the standard time difference. Japan Standard Time is normally 3.5 hours ahead of Indian Standard Time. Whether you are coordinating between teams in Mumbai and New Delhi and Tokyo and Osaka, 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 = 3:30 AM JST. The full 24-hour IST to JST table below uses fixed standard offsets for exact abbreviation searches.
Example: 3:00 PM IST = 6:30 PM JST.
| IST Time | JST Time |
|---|---|
| 12:00 AM (00:00) | 3:30 AM (03:30) |
| 1:00 AM (01:00) | 4:30 AM (04:30) |
| 2:00 AM (02:00) | 5:30 AM (05:30) |
| 3:00 AM (03:00) | 6:30 AM (06:30) |
| 4:00 AM (04:00) | 7:30 AM (07:30) |
| 5:00 AM (05:00) | 8:30 AM (08:30) |
| 6:00 AM (06:00) | 9:30 AM (09:30) |
| 7:00 AM (07:00) | 10:30 AM (10:30) |
| 8:00 AM (08:00) | 11:30 AM (11:30) |
| 9:00 AM (09:00) | 12:30 PM (12:30) |
| 10:00 AM (10:00) | 1:30 PM (13:30) |
| 11:00 AM (11:00) | 2:30 PM (14:30) |
| 12:00 PM (12:00) | 3:30 PM (15:30) |
| 1:00 PM (13:00) | 4:30 PM (16:30) |
| 2:00 PM (14:00) | 5:30 PM (17:30) |
| 3:00 PM (15:00) | 6:30 PM (18:30) |
| 4:00 PM (16:00) | 7:30 PM (19:30) |
| 5:00 PM (17:00) | 8:30 PM (20:30) |
| 6:00 PM (18:00) | 9:30 PM (21:30) |
| 7:00 PM (19:00) | 10:30 PM (22:30) |
| 8:00 PM (20:00) | 11:30 PM (23:30) |
| 9:00 PM (21:00) | 12:30 AM (00:30)+1 day |
| 10:00 PM (22:00) | 1:30 AM (01:30)+1 day |
| 11:00 PM (23:00) | 2:30 AM (02:30)+1 day |
Best time to call Tokyo from Mumbai
For most work calls, compare the normal business day in Mumbai (IST) with the business day in Tokyo (JST). IST commonly covers South Asia, while JST is mainly associated with East Asia.
⚠️ 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.
✅ The most practical overlap on 2026-07-05 is usually 9:30 AM - 2:30 PM IST, which corresponds to 1:00 PM - 6:00 PM JST. This window sits inside the typical IST workday (9:30 AM - 6:30 PM) and the JST workday (9:00 AM - 6:00 PM).
- DST Safety: Neither IST nor JST uses Daylight Saving Time in our dataset, making business-hour relationships stable year-round.
- Bombay Stock Exchange (BSE): 09:15-15:30 local time in Mumbai.
- Tokyo Stock Exchange (TSE): 09:00-15:00 local time in Tokyo.
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Frequently Asked Questions
What is the time difference between IST and JST?
During standard time, Japan Standard Time is 3.5 hours ahead of 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 Japan observe Daylight Saving Time?
Japan has not observed Daylight Saving Time since 1951, when the practice introduced during the Allied occupation was abolished by the Japanese government. JST has remained fixed at UTC+9:00 ever since, and there is no current legislation to reintroduce DST in Japan.
Is JST the same as Korean Standard Time (KST)?
Yes, South Korea's Korean Standard Time (KST) operates at the same UTC+9:00 offset as JST, and South Korea also does not observe Daylight Saving Time. The two countries share an identical clock year-round, which simplifies scheduling for the significant trade, technology, and cultural exchange between Tokyo and Seoul.