IST to JST Converter
Convert India Standard Time (IST) to Japan Standard Time (JST). Pick any date — daylight saving is applied from the IANA time zone database, so the answer is right in March and in November.
IST to JST
IST is 3 hours and 30 minutes behind JST.
Quick answer. JST is 3 hours and 30 minutes ahead of IST, and that gap never changes. Neither IST nor JST observes daylight saving time, so the same conversion is correct on every date of the year.
Time difference
India Standard Time (IST)
IST UTC+5:30 No DST
Mumbai, Delhi, Bengaluru, Chennai, Kolkata, Hyderabad.
India runs on a single time zone, UTC+5:30, and has not observed daylight saving time since 1945. The half-hour offset is why IST conversions rarely land on a round hour.
Japan Standard Time (JST)
JST UTC+9:00 No DST
Tokyo, Osaka, Kyoto, Nagoya, Sapporo, Fukuoka.
Japan has no daylight saving time, so like IST it holds one offset all year. The India–Japan gap is a constant 3 hours 30 minutes.
IST to JST conversion table
Every hour of the day for 2026. Neither side observes daylight saving, so this table is correct on every date of the year.
| IST | JST | 24-hour |
|---|---|---|
| 12 AM | 3:30 AM | 03:30 |
| 1 AM | 4:30 AM | 04:30 |
| 2 AM | 5:30 AM | 05:30 |
| 3 AM | 6:30 AM | 06:30 |
| 4 AM | 7:30 AM | 07:30 |
| 5 AM | 8:30 AM | 08:30 |
| 6 AM | 9:30 AM | 09:30 |
| 7 AM | 10:30 AM | 10:30 |
| 8 AM | 11:30 AM | 11:30 |
| 9 AM | 12:30 PM | 12:30 |
| 10 AM | 1:30 PM | 13:30 |
| 11 AM | 2:30 PM | 14:30 |
| 12 PM | 3:30 PM | 15:30 |
| 1 PM | 4:30 PM | 16:30 |
| 2 PM | 5:30 PM | 17:30 |
| 3 PM | 6:30 PM | 18:30 |
| 4 PM | 7:30 PM | 19:30 |
| 5 PM | 8:30 PM | 20:30 |
| 6 PM | 9:30 PM | 21:30 |
| 7 PM | 10:30 PM | 22:30 |
| 8 PM | 11:30 PM | 23:30 |
| 9 PM | 12:30 AM +1 day | 00:30 |
| 10 PM | 1:30 AM +1 day | 01:30 |
| 11 PM | 2:30 AM +1 day | 02:30 |
Highlighted rows are the 5 hours where a 9–6 working day in IST overlaps a 9–5 working day in JST.
Popular conversion times
| IST | JST |
|---|---|
| 9 AM IST | 12:30 PM |
| 10 AM IST | 1:30 PM |
| 11 AM IST | 2:30 PM |
| 12 PM IST | 3:30 PM |
| 3 PM IST | 6:30 PM |
| 5 PM IST | 8:30 PM |
| 6 PM IST | 9:30 PM |
| 8 PM IST | 11:30 PM |
Business hours and meeting times
Comparing a 9:00–18:00 working day in IST against 9:00–17:00 in JST, across the whole week — a slot only counts if it lands on a working day at both ends.
Both sides work Monday to Friday, so the working weeks line up and you share 5 days.
Rows are days in IST. Columns are hours of the IST day.
Best recurring slot
12 PM IST = 3:30 PM JST , every shared working day
Across the week that is 20 overlapping working hours . The widest day is Monday, with 4 hours.
| Day | Overlap (IST) | Local (JST) | Hours |
|---|---|---|---|
| Monday | 9 AM – 1 PM | 12:30 PM – 4:30 PM | 4 |
| Tuesday | 9 AM – 1 PM | 12:30 PM – 4:30 PM | 4 |
| Wednesday | 9 AM – 1 PM | 12:30 PM – 4:30 PM | 4 |
| Thursday | 9 AM – 1 PM | 12:30 PM – 4:30 PM | 4 |
| Friday | 9 AM – 1 PM | 12:30 PM – 4:30 PM | 4 |
| Saturday | IST weekend | — | — |
| Sunday | IST weekend | — | — |
Public holidays
A shared working day is only usable if neither side is on holiday — and India and JST build their calendars on different systems, so the days each loses rarely coincide.
Over the next 8 weeks you share 40 working days. 6are lost to a public holiday on one side or the other, leaving 34.
| Date | Who is off | Holiday |
|---|---|---|
| Monday, September 21, 2026 | JST | Respect for the Aged Day (敬老の日) |
| Wednesday, September 23, 2026 | JST | Autumnal Equinox Day (秋分の日) |
| Friday, October 2, 2026 | India | Gandhi Jayanti |
| Monday, October 12, 2026 | JST | Sports Day (スポーツの日) |
| Tuesday, October 20, 2026 | India | Dussehra (Vijayadashami) |
| Tuesday, November 3, 2026 | JST | Culture Day (文化の日) |
Next holidays in India
- Friday, October 2, 2026Gandhi Jayantisame date every year
- Tuesday, October 20, 2026Dussehra (Vijayadashami)partialpublished date
- Sunday, November 8, 2026Diwalipublished date
- Monday, November 9, 2026Diwalipublished date
- Friday, December 25, 2026Christmas Daypartialsame date every year
India has three national holidays on which the whole country closes. Everything else is either a central-government gazetted holiday that individual employers choose to observe, or a state holiday. Festival dates follow lunisolar calendars and move every year, so they are listed explicitly rather than derived.
Next holidays in JST
- Monday, September 21, 2026Respect for the Aged Day (敬老の日)published date
- Wednesday, September 23, 2026Autumnal Equinox Day (秋分の日)published date
- Monday, October 12, 2026Sports Day (スポーツの日)published date
- Tuesday, November 3, 2026Culture Day (文化の日)published date
- Monday, November 23, 2026Labour Thanksgiving Day (勤労感謝の日)published date
Public holidays as published by https://date.nager.at, covering 2026–2028. Regional and employer-specific days are not included.
Holiday dates for JST and elsewhere come from a dataset last refreshed on 2026-09-12 (date.nager.at plus curated national calendars). Lunar dates — Eid, Chinese New Year, the Jewish holidays — are predicted and can move by a day once officially announced. Regional, state and employer-specific holidays are not included. Confirm anything you are booking a flight around.
About this conversion
India runs on a single time zone, UTC+5:30, and has not observed daylight saving time since 1945. The half-hour offset is why IST conversions rarely land on a round hour.
Japan has no daylight saving time, so like IST it holds one offset all year. The India–Japan gap is a constant 3 hours 30 minutes.
Frequently asked questions
What is the time difference between IST and JST?
JST is 3 hours and 30 minutes ahead of IST, on every date of the year. Neither side observes daylight saving time.
What time is 9 AM IST in JST?
9:00 AM IST is 12:30 PM in JST, all year round.
What is the best time for a meeting between IST and JST?
Working days overlap for about 4 hours on a typical Monday: 9 AM to 1 PM IST, which is 12:30 PM to 4:30 PM in JST. For a recurring invite, 12 PM IST / 3:30 PM JST is the slot that works on the most days.
Does India observe daylight saving time?
No. India has kept a single UTC+5:30 offset since 1945 and does not use daylight saving time, so IST reads the same on every date of the year. Any change in the gap to JST comes entirely from the other side.
How many hours a week do IST and JST actually overlap?
20 hours across the week, spread over 5 working days. 12 PM IST (3:30 PM JST) is the slot that works on the most days, so it is the one to put in a recurring invite.
Do public holidays in IST and JST line up?
Barely. Over the next eight weeks the two sides share 40 working days, and 6 of those are a public holiday on one side or the other, leaving 34. The next holiday in JST is Respect for the Aged Day (敬老の日) on 2026-09-21. Indian, Gulf and Western holiday calendars are built on different systems, so the days each side loses rarely coincide.
Is IST ahead of JST?
No, it is the other way around: JST is ahead of IST by 3 hours and 30 minutes.
Cities on the same clock as JST
These keep an identical offset, so every conversion on this page applies to them too.
- IST to Tokyo · same clock
Related converters
- IST to EST · Eastern Time
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- IST to MST · Mountain Time