A Business Activity Statement (BAS) is a tax reporting form lodged with the Australian Taxation Office (ATO) by businesses registered for GST. It consolidates several tax obligations into a single submission: most commonly GST collected on sales, GST paid on purchases, PAYG withholding amounts deducted from staff wages, and PAYG instalments toward the business's own income tax.
Lodgement frequency
Most small businesses lodge BAS quarterly. Businesses with annual GST turnover of $20 million or more must lodge monthly. Very small businesses (under $75,000 GST turnover) may elect to lodge annually, although they still pay GST instalments quarterly.
Due dates and penalties
BAS due dates fall 28 days after the end of the period. Registered tax and BAS agents receive an automatic extension — commonly to the 25th of the month following the period end, with further lodgement concessions under the ATO's PLS schedule. Late lodgement attracts failure-to-lodge penalties and general interest charges on unpaid amounts.
Key BAS labels
- G1 — Total sales (including GST)
- G3 — GST-free sales
- G4 — Input-taxed sales
- G10 — Capital purchases
- G11 — Non-capital purchases
- 1A — GST on sales (to pay)
- 1B — GST on purchases (input tax credits to claim)
- W1 — Total salary and wages
- W2 — PAYG withholding
- T1 — PAYG instalment income
Common mistakes
- Claiming input tax credits without a valid tax invoice (required for purchases over $82.50 including GST).
- Misclassifying GST-free or input-taxed sales as taxable, inflating the GST liability.
- Forgetting to include cash sales or income from online platforms.
- Reconciling bank deposits rather than accrual-based GST turnover when using the accruals basis.
Accelete generates a review-ready BAS draft from clients' bank feeds and AI-categorised transactions, so registered tax and BAS agents spend their time reviewing exceptions instead of typing line items.