JST to IST converter
Japan Standard Time to India Standard Time. IST is 3 h 30 min behind of JST all year.
From
JST · Tokyo GMT+9 · UTC+9
- IST · KolkataUTC+5:30 · 3 h 30 min behind05:30Mon, Sep 28
The gap between JST and IST
| 2026 | JST clocks | IST clocks | Difference |
|---|---|---|---|
| January | GMT+9 UTC+9 | GMT+5:30 UTC+5:30 | 3 h 30 min behind |
| July | GMT+9 UTC+9 | GMT+5:30 UTC+5:30 | 3 h 30 min behind |
Neither clock changes relative to the other, so this gap holds all year.
Convert the other way: IST to JST · Plan a meeting across more places
JST to IST time table
Every hour of the JST day and the matching IST time, for a mid-January and a mid-July date (they are identical, since the gap never changes).
| JST | IST · January |
|---|---|
| 12:00 AM | 8:30 PM (−1 day) |
| 1:00 AM | 9:30 PM (−1 day) |
| 2:00 AM | 10:30 PM (−1 day) |
| 3:00 AM | 11:30 PM (−1 day) |
| 4:00 AM | 12:30 AM |
| 5:00 AM | 1:30 AM |
| 6:00 AM | 2:30 AM |
| 7:00 AM | 3:30 AM |
| 8:00 AM | 4:30 AM |
| 9:00 AM | 5:30 AM |
| 10:00 AM | 6:30 AM |
| 11:00 AM | 7:30 AM |
| 12:00 PM | 8:30 AM |
| 1:00 PM | 9:30 AM |
| 2:00 PM | 10:30 AM |
| 3:00 PM | 11:30 AM |
| 4:00 PM | 12:30 PM |
| 5:00 PM | 1:30 PM |
| 6:00 PM | 2:30 PM |
| 7:00 PM | 3:30 PM |
| 8:00 PM | 4:30 PM |
| 9:00 PM | 5:30 PM |
| 10:00 PM | 6:30 PM |
| 11:00 PM | 7:30 PM |
About these two clocks
JST — Japan Standard Time. Used in Tokyo, Osaka. Japan has no daylight saving time; it is UTC+9 all year.
IST — India Standard Time. Used in all of India — Mumbai, Delhi, Bengaluru. India does not use daylight saving time, so IST is UTC+5:30 all year.
All figures on this page come from the IANA time zone database (the same data your phone and laptop use), evaluated for the date in question. Abbreviations are ambiguous — “IST” also means Irish or Israel Standard Time, and “CST” is China Standard Time in Asia — so this page uses Asia/Tokyo and Asia/Kolkata explicitly.
Questions people ask
How many hours ahead or behind is IST compared with JST?
IST is 3 h 30 min behind of JST all year, because the offset between the two clocks does not change.
What is 9 am JST in IST?
On a January date, 9:00 am JST is 5:30 AM IST. Use the converter above for any other date.
Which cities use JST?
Japan Standard Time (JST) is used in Tokyo, Osaka. Japan has no daylight saving time; it is UTC+9 all year.
Which cities use IST?
India Standard Time (IST) is used in all of India — Mumbai, Delhi, Bengaluru. India does not use daylight saving time, so IST is UTC+5:30 all year.
When is a good time for a JST–IST call?
Look for the hours where both columns in the table fall between about 8 am and 6 pm. If none exist, the meeting planner on our home page shows the least-bad options and lets you share a link that converts for every attendee.
Related conversions
EST to ISTUTC to ISTCST to ISTPST to ISTCET to ISTGMT to ISTBST to ISTSGT to ISTJST to ESTAEST to IST