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September 19, 2025BAS & GST

What Is BAS and How to Lodge It Correctly: A Guide for Australian Businesses

What is a BAS (Business Activity Statement)?

A Business Activity Statement (BAS) is the official form Australian businesses use to report and pay taxes to the Australian Taxation Office (ATO). It covers GST collected and paid, PAYG withholding, and other tax obligations. If your business is registered for GST, you must lodge a BAS monthly, quarterly, or annually depending on your turnover and reporting preference.

Who needs to lodge a BAS in Australia?

Businesses with annual turnover exceeding $75,000 (or $150,000 for non-profits) must register for GST and lodge BAS statements. Even when no transactions occur, businesses must lodge a "nil" BAS by the deadline. Non-compliance results in ATO penalties, interest charges, and potential audits.

When is the BAS due?

For most small-to-medium businesses lodging quarterly:

  • Q1 (July–September): Due 28 October
  • Q2 (October–December): Due 28 February
  • Q3 (January–March): Due 28 April
  • Q4 (April–June): Due 28 July

Businesses with GST turnover exceeding $20 million report monthly by the 21st of the following month. Lodging through a registered BAS agent often grants an extended due date — use our BAS Due Date Calculator to confirm your deadline.

How do I lodge my BAS?

You can lodge via:

  • ATO app or Business Portal
  • Cloud accounting software (Xero, QuickBooks)
  • Registered BAS agent
  • Paper forms
  • Automated phone service (nil returns only)

What are the most common BAS mistakes?

  • Incorrect GST reporting — mixing up GST-inclusive vs exclusive amounts, or claiming credits on ineligible purchases
  • Poor record-keeping — disorganised documentation and commingled personal and business expenses
  • Omitted liabilities — forgetting fringe benefits tax or luxury car tax obligations
  • Data entry errors — calculation mistakes and wrong labels
  • Late lodgement — triggers an ATO Failure to Lodge (FTL) penalty of $313 per 28-day period for small businesses, up to $1,565

What is the BAS lodgement checklist?

  1. Confirm your active ABN and GST registration
  2. Gather all invoices and payroll records for the period
  3. Calculate total sales, purchases, net GST, and PAYG amounts
  4. Complete all BAS fields with correct labels (G1, G2, W1 etc.)
  5. Cross-reference figures against your accounting records in Xero
  6. Submit and pay any amount owing by the due date
  7. Keep a copy of the lodged BAS for your records

The Metier Group provides registered BAS agent services across Perth. Contact us for professional BAS lodgement support.