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. South Korea does not observe daylight saving, so KST applies all year. It shares an offset with Japan.
AEST is ahead of KST by 1 hours today
On 19 August 2026, Australian Eastern Standard Time is on AEST at UTC+10:00 and Korea Standard Time is on KST at UTC+09:00. The gap between them is 1 hours, with KST behind. So 9:00 am in AEST is 8:00 am in KST, and 5:00 pm in AEST is 4:00 pm in KST. Going the other way, see KST 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. Korea 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 Korea 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 7 overlapping hours in a normal day. In AEST that window runs from 10:00 am to 5:00 pm, which is 9:00 am to 4:00 pm in KST. 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 1-hour gap above.