MeetingTimePro

IST to JST converter

India Standard Time to Japan Standard Time. JST is 3 h 30 min ahead of IST all year.

From

IST · Kolkata GMT+5:30 · UTC+5:30

  • JST · TokyoUTC+9 · 3 h 30 min ahead
    12:30Mon, Sep 28
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The gap between IST and JST

2026IST clocksJST clocksDifference
JanuaryGMT+5:30 UTC+5:30GMT+9 UTC+93 h 30 min ahead
JulyGMT+5:30 UTC+5:30GMT+9 UTC+93 h 30 min ahead

Neither clock changes relative to the other, so this gap holds all year.

Convert the other way: JST to IST · Plan a meeting across more places

IST to JST time table

Every hour of the IST day and the matching JST time, for a mid-January and a mid-July date (they are identical, since the gap never changes).

ISTJST · January
12:00 AM3:30 AM
1:00 AM4:30 AM
2:00 AM5:30 AM
3:00 AM6:30 AM
4:00 AM7:30 AM
5:00 AM8:30 AM
6:00 AM9:30 AM
7:00 AM10:30 AM
8:00 AM11:30 AM
9:00 AM12:30 PM
10:00 AM1:30 PM
11:00 AM2:30 PM
12:00 PM3:30 PM
1:00 PM4:30 PM
2:00 PM5:30 PM
3:00 PM6:30 PM
4:00 PM7:30 PM
5:00 PM8:30 PM
6:00 PM9:30 PM
7:00 PM10:30 PM
8:00 PM11:30 PM
9:00 PM12:30 AM (+1 day)
10:00 PM1:30 AM (+1 day)
11:00 PM2:30 AM (+1 day)

About these two clocks

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.

JST — Japan Standard Time. Used in Tokyo, Osaka. Japan has no daylight saving time; it is UTC+9 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/Kolkata and Asia/Tokyo explicitly.

Questions people ask

How many hours ahead or behind is JST compared with IST?

JST is 3 h 30 min ahead of IST all year, because the offset between the two clocks does not change.

What is 9 am IST in JST?

On a January date, 9:00 am IST is 12:30 PM JST. Use the converter above for any other date.

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.

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.

When is a good time for a IST–JST 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

IST to ESTIST to UTCIST to CSTIST to PSTIST to GMTIST to CETIST to AESTEST to JSTPST to JST