What is a Business Activity Statement (BAS)?
A Business Activity Statement is the ATO’s periodic report where businesses declare indirect tax activity and certain instalments. On each BAS you report:
- GST collected on sales (output tax) and GST paid on business purchases (input tax credits)
- PAYG withholding amounts you’ve withheld from employees’ wages
- PAYG income tax instalments (ATO pre‑calculated or varied amounts)
- Any other applicable items such as FBT instalments, Wine Equalisation Tax, Luxury Car Tax and Fuel Tax Credits
Not every business reports every item. Your BAS will display only the obligations that apply to you based on registrations. If you do not have GST but still need to report PAYG withholding or PAYG instalments, you might receive an IAS (Instalment Activity Statement) instead of a BAS.
Who must lodge and when
- You must lodge a BAS if you are registered for GST, withhold PAYG from employees, or pay PAYG instalments.
- Lodgement frequency is typically:
- Quarterly for most small businesses: Q1 (Jul–Sep) due 28 Oct; Q2 (Oct–Dec) due 28 Feb; Q3 (Jan–Mar) due 28 Apr; Q4 (Apr–Jun) due 28 Jul.
- Monthly for businesses with higher turnover or specific obligations: usually due on the 21st of the following month.
- Annual GST if eligible and elected, with conditions.
- Registered BAS agents and tax agents may access extended deadlines under the ATO lodgement program.
If you’re unsure whether you should be registered for GST, a quick rule of thumb is that you must register when your GST turnover meets or is likely to meet $75,000 ($150,000 for non‑profits). Some businesses choose to register earlier for cash flow or client perception reasons.
What the BAS includes and how to prepare it
GST on sales and purchases
Ensure tax codes are applied correctly to sales and expenses, check GST‑free and input‑taxed items, and reconcile GST collected vs GST paid. Run and review the GST detail report in your software before you lodge.
PAYG withholding (W1/W2)
Confirm gross wages and PAYG withholding match your payroll reports and Single Touch Payroll (STP) figures. Fix payroll coding issues before lodging to avoid ATO mismatches.
PAYG instalments (T1/T7/T8)
The ATO may pre‑fill an instalment amount. You can pay as shown or vary it if circumstances change, but variations must be reasonable to avoid penalties. Keep evidence of how you calculated any variation.
Other items (if applicable)
Some businesses report FBT instalments, Fuel Tax Credits, Wine Equalisation Tax or Luxury Car Tax. Check eligibility and rates each period—these often change and have specific record‑keeping rules.
Preparation checklist:
- Complete bank feeds and reconcile all bank, card and loan accounts for the period
- Review GST coding for unusual, capital, entertainment and cross‑border transactions
- Match payroll summaries to STP and superannuation accruals
- Confirm outstanding invoices/bills and clear duplicates or miscodings
- Export and file copies of your BAS reports and working papers
Best next steps
If you’re lodging for the first time, behind on BAS, or not confident in your figures, get a short BAS health check. A registered BAS agent or accountant can spot GST coding errors, payroll mismatches and reconciliation gaps quickly.
Decide your approach:
- DIY with software (Xero, MYOB, QuickBooks) if your records are clean and you understand GST/STP
- Use a BAS agent for compliance‑focused preparation and lodgement
- Work with an accountant if you also need broader tax and advisory support
- Add bookkeeping services to keep your data accurate between BAS periods
If you’ve made a mistake, you can usually amend a later BAS or lodge a revision. If you’re late or have cash flow pressure, consider an ATO payment plan and engage a professional to help you catch up.
Frequently asked questions
What Is a Business Activity Statement?
A BAS is the ATO’s periodic form for reporting GST, PAYG withholding, PAYG income tax instalments and certain other indirect taxes. It determines what you owe or what credit you can claim for the period.
Who needs to lodge a BAS and how often?
Businesses registered for GST, those that withhold PAYG from wages, or those paying PAYG instalments must lodge. Most small businesses lodge quarterly (28 Oct, 28 Feb, 28 Apr, 28 Jul). Monthly lodgers are generally due on the 21st of the following month. Agent extensions may apply.
How do I lodge a BAS?
Common options are lodging through your accounting software, via ATO Online Services, or engaging a registered BAS agent or accountant to prepare and lodge on your behalf. Ensure your records are reconciled and reports reviewed first.
What if I get it wrong or I’m running late?
You can correct errors via a later BAS or by lodging a revision. If you’re late, ATO penalties and interest may apply. A BAS agent can help you triage issues, fix coding errors, and set up a payment arrangement if needed.