BAS Deadline Calculator

About This Tool

A Business Activity Statement (BAS) is the form used to report and pay GST, PAYG withholding, PAYG instalments and some other taxes. Most small businesses lodge quarterly. Businesses with GST turnover of $20 million or more must lodge monthly. This page looks up the standard legislative due date for a 2026–27 monthly or quarterly period. It does not look up the date printed on your activity statement when that date is different.

Why This Matters for Australian Businesses

Late lodgment can attract a failure to lodge on time penalty. Late payment can attract general interest charge. The date that applies to your account can differ from the standard legislative date if you lodge through a registered agent, qualify for the extra 2 weeks some online quarterly lodgers receive, or have another concession. Use the date on your activity statement when it differs from this lookup.

Supported 2026–27 standard due dates

Legislative dates below match the ATO generate-dates table (updated 2026-06-16, checked 2026-09-08). Lodge and pay by the next working day when the legislative date is a weekend or a public holiday in any state or territory. Agent and online-concession dates are not in this table.

Quarterly

Monthly

How to Use This Tool

1. Select quarterly or monthly reporting. Annual GST returns are not looked up — use ATO guidance
2. Select the 2026–27 reporting period
3. Look up the standard legislative due date, shown in Australian calendar terms
4. If that date is a weekend or a public holiday in any state or territory, lodge and pay by the next working day shown

Key Rules & Thresholds

• Monthly BAS: 21st day of the following month (ATO generate dates 2026–27)
• Quarterly BAS: 28 October, 28 February (quarter 2), 28 April and 28 July
• Quarter 2 already includes a one-month holiday concession, so the extra 2 weeks and the standard agent concession do not apply
• December monthly legislative due date is 21 January, not 21 February. 21 February is a registered-agent concession for eligible monthly GST clients
• If a legislative due date is a weekend or a public holiday for the whole of any state or territory, lodge and pay by the next working day
• Some online quarterly lodgers get an extra 2 weeks on quarters 1, 3 and 4. That date appears on the activity statement and is not computed here
• Annual GST returns are due with the tax return, or 28 February if there is no tax-return lodgment obligation

How Results Are Calculated

The lookup uses the ATO 2026–27 legislative due dates: the 21st of the following month for monthly BAS, and 28 October, 28 February, 28 April and 28 July for quarterly BAS. Quarter 2 is 28 February, not 28 January. If that calendar date is a Saturday, a Sunday, or a public holiday the ATO lists for any state or territory, the date shown is the next working day. Dates are built from year-month-day parts so a browser timezone cannot shift the Australian calendar day. Agent lodgment-program dates, the extra 2 weeks some online quarterly lodgers receive, December monthly 21 February concessions, annual GST returns and other account-specific dates are out of scope.

Official Resources

• ATO — Due dates for lodging and paying your BAS
• ATO — Activity statement generate dates
• ATO — Lodgment and payment dates on weekends or public holidays
• ATO — BAS agent lodgment program 2026–27
• ATO — Two week lodgment concession
• ATO — Failure to lodge on time penalty