The self-lodgement tax deadline falls on 31 October every year, closing the four-month window that opened on 1 July. 23 October 2027 falls inside October, the final month of that window, in the fourth calendar quarter of 2027, with the deadline drawing closer as the month progresses.
Saturday 23 October 2027 is a weekend day under the standard Monday-to-Friday working pattern and does not count toward the working-day total shown above. Retail, hospitality, healthcare and emergency services staff commonly work rostered shifts on this day regardless of the standard week that applies to most other industries and workplaces across the country.
The quarter containing 23 October 2027 is based on the calendar year running January to December, a separate system from the Australian financial year, which runs from 1 July to 30 June and splits into its own four quarters. Businesses often track both systems side by side, one for tax filings and one for calendar-year planning.