What is the time difference between Kolkata and Sydney?

Sydney is 4 hours 30 minutes ahead of Kolkata. That figure is current — it changes by an hour when either city starts or ends daylight saving, and the exact dates are listed above.

When is the best time to call Sydney from Kolkata?

Between 09:00–13:30 in Kolkata, which is 13:30–18:00 in Sydney. That is the only stretch where both cities are inside a 09:00–18:00 day.

Does Kolkata observe daylight saving time?

No. Kolkata stays on UTC+5:30 all year, so its clocks never move.

Does Sydney observe daylight saving time?

Yes. Sydney runs on UTC+10 in winter and UTC+11 in summer. The next change is on 2026-10-04, when clocks go forward by 60 minutes.

If it is midday in Kolkata, what time is it in Sydney?

It is 16:30 in Sydney, on the same calendar date. That holds for the current offsets; it shifts by an hour around the daylight saving dates listed above.

Which time zones do Kolkata and Sydney use?

Kolkata uses Asia/Kolkata, currently UTC+5:30 (IST), and Sydney uses Australia/Sydney, currently UTC+10 (AEST). Those identifiers are the ones to use in code — abbreviations are ambiguous and offsets change.

Convert Kolkata time to Sydney time

Right now Sydney runs 4 hours 30 minutes ahead of Kolkata. That gap is not fixed: it moves when either city changes its clocks.

Convert a time

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Date

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Converted time

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The converter needs JavaScript to run. Everything below — offsets, daylight saving dates and the hour-by-hour table — is part of the page and works without it.

Hour by hour

The whole day mapped across: read down the left for Kolkata, across for Sydney.

Kolkata	Sydney
00:00	04:30
01:00	05:30
02:00	06:30
03:00	07:30
04:00	08:30
05:00	09:30
06:00	10:30
07:00	11:30
08:00	12:30
09:00	13:30
10:00	14:30
11:00	15:30
12:00	16:30
13:00	17:30
14:00	18:30
15:00	19:30
16:00	20:30
17:00	21:30
18:00	22:30
19:00	23:30
20:00	00:30next day
21:00	01:30next day
22:00	02:30next day
23:00	03:30next day

Daylight saving time

Sydney changes its clocks; Kolkata does not. The difference between them therefore shifts by an hour twice a year.

Kolkata

Does not observe daylight saving time

Standard: UTC+5:30

Sydney

Observes daylight saving time

Standard: UTC+10
Daylight: UTC+11
Next change: 2026-10-04 +60m

When you can actually talk

You have 4 hours 30 minutes of shared working time: 09:00–13:30 in Kolkata, which is 13:30–18:00 in Sydney.

Kolkata 09:00–13:30Sydney 13:30–18:00

Reference

The zone identifiers and offsets behind everything above.

	Kolkata	Sydney
IANA zone	Asia/Kolkata	Australia/Sydney
Abbreviation	IST	AEST
Standard offset	UTC+5:30	UTC+10
Daylight offset	—	UTC+11
Clock changes this year	0	2
Country	India	Australia

Example, not the current time. Live times appear once the page loads.

Common questions

What is the time difference between Kolkata and Sydney?: Sydney is 4 hours 30 minutes ahead of Kolkata. That figure is current — it changes by an hour when either city starts or ends daylight saving, and the exact dates are listed above.
When is the best time to call Sydney from Kolkata?: Between 09:00–13:30 in Kolkata, which is 13:30–18:00 in Sydney. That is the only stretch where both cities are inside a 09:00–18:00 day.
Does Kolkata observe daylight saving time?: No. Kolkata stays on UTC+5:30 all year, so its clocks never move.
Does Sydney observe daylight saving time?: Yes. Sydney runs on UTC+10 in winter and UTC+11 in summer. The next change is on 2026-10-04, when clocks go forward by 60 minutes.
If it is midday in Kolkata, what time is it in Sydney?: It is 16:30 in Sydney, on the same calendar date. That holds for the current offsets; it shifts by an hour around the daylight saving dates listed above.
Which time zones do Kolkata and Sydney use?: Kolkata uses Asia/Kolkata, currently UTC+5:30 (IST), and Sydney uses Australia/Sydney, currently UTC+10 (AEST). Those identifiers are the ones to use in code — abbreviations are ambiguous and offsets change.