Which zone this page means. AEST applies in winter; AEDT (UTC+11) applies from the first Sunday in October to the first Sunday in April. Australian seasons are reversed, so summer time runs over the southern summer. Queensland stays on AEST all year. IST means India Standard Time (UTC+5:30), Irish Standard Time (UTC+1) and Israel Standard Time (UTC+2). This page means the Indian zone, which is one of the few on a half-hour offset.
AEST is ahead of IST by 4.5 hours today
On 19 August 2026, Australian Eastern Standard Time is on AEST at UTC+10:00 and India Standard Time is on IST at UTC+05:30. The gap between them is 4.5 hours, with IST behind. So 9:00 am in AEST is 4:00 am in IST, and 5:00 pm in AEST is 12:00 pm in IST. Going the other way, see IST to AEST.
The gap is not constant, and that is the part that catches people out
Australian Eastern Standard Time is currently on standard time and changes next on 4 October 2026, when clocks go forward an hour. India Standard Time does not observe daylight saving at all, so the whole of the seasonal change comes from the AEST side: the gap moves by an hour twice a year even though nothing changes in India Standard Time.
When you can actually both be at work
Taking a working day as 9:00 am to 5:00 pm local at each end, there are 3 overlapping hours in a normal day. In AEST that window runs from 2:00 pm to 5:00 pm, which is 9:00 am to 12:00 pm in IST. Anything outside it needs one side to start early or finish late.
Zone rules are set by legislation and change, sometimes at short notice. This page is built against tzdata 2026a, last reviewed 2026-08-18. Quarterly. Zone rules change by legislation, sometimes at short notice. Version and review date are shown on every zone page. The converter above reads your browser's own copy of the zone database, so if a rule has changed since this page was built the live answer follows the new rule.
Every convention used above — whether the start date counts, how month ends are clamped, which holidays close an office — is written out on the methodology page, including the daylight-saving rules behind the 4.5-hour gap above.