BAS Quarterly Due Dates Calculator (Australia)
When is your Business Activity Statement due? This calculator gives you the exact ATO lodgement deadline for any Australian quarterly BAS, including the concessional dates for businesses that lodge through a registered tax or BAS agent. Covers FY2025-26 and FY2026-27.
BAS quarterly due dates by financial year
| Quarter | Period covered | Self-lodge | Tax / BAS agent |
|---|---|---|---|
| Q1 (Jul–Sep) | 1 Jul — 30 Sep | 28 Oct | 25 Nov (approx) |
| Q2 (Oct–Dec) | 1 Oct — 31 Dec | 28 Feb | 28 Feb (no extension) |
| Q3 (Jan–Mar) | 1 Jan — 31 Mar | 28 Apr | 26 May (approx) |
| Q4 (Apr–Jun) | 1 Apr — 30 Jun | 28 Jul | 25 Aug (approx) |
Note: Q2's tax agent concession is unchanged because of the December holiday period. The other quarter concessions reflect the ATO's standard tax-agent extensions and may shift if the date falls on a weekend or public holiday.
Monthly BAS due dates
If you lodge monthly (most commonly because your annual GST turnover is $20 million or more, or you've elected to do so), each monthly BAS is due by the 21st of the following month. Monthly lodgers don't get the tax-agent concession that applies to quarterly lodgers.
Example: BAS for May activity is due 21 June. If 21 June falls on a weekend, the deadline shifts to the next business day.
Annual BAS due dates
Small businesses voluntarily registered for GST (GST turnover under $75,000, or $150,000 for non-profits) can lodge BAS annually. The annual BAS is due with the income tax return:
- Self-lodge: 31 October following the end of the financial year
- Through a tax agent: by the agent's lodgement program due date (typically up to 15 May the following year)
What happens if you lodge BAS late
The ATO can apply a Failure to Lodge (FTL) penalty plus general interest charge (GIC) on any unpaid GST. The FTL penalty is calculated as:
- 1 penalty unit ($330 as at November 2024) for each 28-day block, or part block, the BAS is late
- Capped at 5 penalty units for small entities (turnover < $1 million)
- Capped higher for medium and large entities (multipliers apply)
If you have a clean lodgement record, the ATO may remit (waive) penalties automatically. If not, you can call 13 28 66 to request remission.
How to lodge BAS
- Online via ATO Online Services (mygov.au linked) or the Business Portal — free, immediate confirmation
- Through your tax/BAS agent — gets the concessional due dates automatically
- Via Standard Business Reporting (SBR) — if your accounting software supports it (Xero, MYOB, QuickBooks all do)
- By mail — paper BAS form, slow but allowed
Need to count down to a BAS deadline?
Use the Days From Date Calculator to count exactly how many days until your next BAS is due.
Open Days From Date CalculatorFrequently asked questions
Official sources
- Australian Taxation Office — Business Activity Statements
- ATO — Due dates for lodging and paying BAS
- ATO — Penalty units and amounts
This calculator and guide are general information only and not tax advice. ATO due dates can shift if they fall on a weekend or public holiday. Always confirm the exact date in your ATO Online Services account or with your tax agent.