IST to AEST Converter
Convert India Standard Time (IST) to Australian Eastern Time (AEST/AEDT). 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 AEST
IST is 4 hours and 30 minutes behind AEST.
Quick answer. AEST is 5 hours and 30 minutes ahead of IST for part of the year and 4 hours and 30 minutes ahead for the rest, because AEST observes daylight saving time and the other side does not. The gap is 5 hours and 30 minutes during AEST's standard-time months and 4 hours and 30 minutes during daylight time, so always convert against a specific date.
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.
Australian Eastern Time (AEST/AEDT)
AEST UTC+10:00 AEDT UTC+11:00 Observes DST
Sydney, Melbourne, Canberra, Brisbane (AEST year-round), Hobart.
- ↓ April 5, 2026 clocks back at 2:00 AM · UTC+11:00 → UTC+10:00
- ↑ October 4, 2026 clocks forward at 3:00 AM · UTC+10:00 → UTC+11:00
Australian daylight saving runs opposite to the northern hemisphere: clocks go forward in October and back in April, so the India–Sydney gap is widest during the Indian winter. Queensland, including Brisbane, stays on AEST all year.
IST to AEST conversion table
Every hour of the day for 2026. Because AEST changes clocks twice a year, these values shift by an hour across the daylight saving boundary — use the date picker above for a specific day.
| IST | AEST | 24-hour |
|---|---|---|
| 12 AM | 4:30 AM | 04:30 |
| 1 AM | 5:30 AM | 05:30 |
| 2 AM | 6:30 AM | 06:30 |
| 3 AM | 7:30 AM | 07:30 |
| 4 AM | 8:30 AM | 08:30 |
| 5 AM | 9:30 AM | 09:30 |
| 6 AM | 10:30 AM | 10:30 |
| 7 AM | 11:30 AM | 11:30 |
| 8 AM | 12:30 PM | 12:30 |
| 9 AM | 1:30 PM | 13:30 |
| 10 AM | 2:30 PM | 14:30 |
| 11 AM | 3:30 PM | 15:30 |
| 12 PM | 4:30 PM | 16:30 |
| 1 PM | 5:30 PM | 17:30 |
| 2 PM | 6:30 PM | 18:30 |
| 3 PM | 7:30 PM | 19:30 |
| 4 PM | 8:30 PM | 20:30 |
| 5 PM | 9:30 PM | 21:30 |
| 6 PM | 10:30 PM | 22:30 |
| 7 PM | 11:30 PM | 23:30 |
| 8 PM | 12:30 AM +1 day | 00:30 |
| 9 PM | 1:30 AM +1 day | 01:30 |
| 10 PM | 2:30 AM +1 day | 02:30 |
| 11 PM | 3:30 AM +1 day | 03:30 |
Highlighted rows are the 4 hours where a 9–6 working day in IST overlaps a 9–5 working day in AEST.
Popular conversion times
| IST | AEST |
|---|---|
| 9 AM IST | 1:30 PM |
| 10 AM IST | 2:30 PM |
| 11 AM IST | 3:30 PM |
| 12 PM IST | 4:30 PM |
| 3 PM IST | 7:30 PM |
| 5 PM IST | 9:30 PM |
| 6 PM IST | 10:30 PM |
| 8 PM IST | 12:30 AM+1 day |
Business hours and meeting times
Comparing a 9:00–18:00 working day in IST against 9:00–17:00 in AEST, 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
11 AM IST = 3:30 PM AEST , every shared working day
Across the week that is 15 overlapping working hours . The widest day is Monday, with 3 hours.
| Day | Overlap (IST) | Local (AEST) | Hours |
|---|---|---|---|
| Monday | 9 AM – 12 PM | 1:30 PM – 4:30 PM | 3 |
| Tuesday | 9 AM – 12 PM | 1:30 PM – 4:30 PM | 3 |
| Wednesday | 9 AM – 12 PM | 1:30 PM – 4:30 PM | 3 |
| Thursday | 9 AM – 12 PM | 1:30 PM – 4:30 PM | 3 |
| Friday | 9 AM – 12 PM | 1:30 PM – 4:30 PM | 3 |
| Saturday | IST weekend | — | — |
| Sunday | IST weekend | — | — |
Public holidays
A shared working day is only usable if neither side is on holiday — and India and AEST 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 |
|---|---|---|
| Friday, September 25, 2026 | AEST | Friday before AFL Grand Final |
| Monday, September 28, 2026 | AEST | King's Birthday |
| Friday, October 2, 2026 | India | Gandhi Jayanti |
| Monday, October 5, 2026 | AEST | Labour Day / King's Birthday |
| Tuesday, October 20, 2026 | India | Dussehra (Vijayadashami) |
| Tuesday, November 3, 2026 | AEST | Melbourne Cup |
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 AEST
- Friday, September 25, 2026Friday before AFL Grand Finalregionalpublished date
- Monday, September 28, 2026King's Birthdayregionalpublished date
- Monday, October 5, 2026Labour Day / King's Birthdayregionalpublished date
- Tuesday, November 3, 2026Melbourne Cupregionalpublished date
- Friday, December 25, 2026Christmas Daypublished date
Public holidays as published by https://date.nager.at, covering 2026–2028. Regional and employer-specific days are not included.
Holiday dates for AEST 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.
Australian daylight saving runs opposite to the northern hemisphere: clocks go forward in October and back in April, so the India–Sydney gap is widest during the Indian winter. Queensland, including Brisbane, stays on AEST all year.
Frequently asked questions
What is the time difference between IST and AEST?
It depends on the date. AEST is 5 hours and 30 minutes ahead of IST in January and 4 hours and 30 minutes ahead in July, because AEST changes clocks for daylight saving time. Use the converter above with the date you actually need.
What time is 9 AM IST in AEST?
9:00 AM IST is 2:30 PM in AEST during AEST, and 1:30 PM during AEDT. The table on this page lists all 24 hours for the date you pick.
What is the best time for a meeting between IST and AEST?
Working days overlap for about 3 hours on a typical Monday: 9 AM to 12 PM IST, which is 1:30 PM to 4:30 PM in AEST. For a recurring invite, 11 AM IST / 3:30 PM AEST 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 AEST comes entirely from the other side.
When do the clocks change in AEST?
In 2026, clocks in AEST go forward on October 4, 2026 and back on April 5, 2026. Between those dates the gap from India is 4 hours and 30 minutes; outside them it is 5 hours and 30 minutes.
Why does the IST–AEST difference change during the year?
Because AEST switches between AEST (UTC+10:00) and AEDT (UTC+11:00) for daylight saving, while the other side does not move. A converter that assumes one fixed gap will be an hour wrong for roughly half the year.
How many hours a week do IST and AEST actually overlap?
15 hours across the week, spread over 5 working days. 11 AM IST (3:30 PM AEST) 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 AEST 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 AEST is Friday before AFL Grand Final on 2026-09-25. Indian, Gulf and Western holiday calendars are built on different systems, so the days each side loses rarely coincide.
Is IST ahead of AEST?
No, it is the other way around: AEST is ahead of IST by 4 hours and 30 minutes to 5 hours and 30 minutes.
Converting the other way
Looking up times starting from AEST? Use the AEST to IST converter, which leads with AEST as the starting point and is written for that reader.
Cities on the same clock as AEST
These keep an identical offset, so every conversion on this page applies to them too.
- IST to Sydney · same clock
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