Business Activity Statement (BAS): What It Is and How to Lodge

Business Activity Statement (BAS): What It Is and How to Lodge

A Business Activity Statement (BAS) is a form you submit to the Australian Taxation Office (ATO) to report and pay several tax obligations at once. If you are registered for GST, you are required to lodge a BAS. It is one of the most important compliance obligations for Australian businesses and sole traders.

What Does a BAS Cover?

A BAS can include several different tax obligations depending on your business circumstances:

  • GST — the GST you collected on your sales (GST on sales) minus the GST credits you are claiming on your purchases (input tax credits). The net amount is what you pay to the ATO, or what the ATO refunds to you.
  • PAYG withholding — if you have employees, you must withhold tax from their wages and report and remit this to the ATO via your BAS
  • PAYG instalments — if you have a large personal tax liability from business income, the ATO may require you to pre-pay your income tax in quarterly instalments throughout the year
  • Fuel tax credits — if your business uses fuel in eligible activities, you can claim a credit on your BAS
  • Wine equalisation tax (WET) — applies to wine producers and sellers; reported on the BAS if applicable

Not all businesses will have all of these obligations. A sole trader with no employees who is registered only for GST will typically only have GST to report.

How Often Do You Lodge?

Your BAS lodgement frequency depends on the size of your business:

  • Monthly — required if your GST turnover is $20 million or more; some businesses with complex tax affairs also lodge monthly by choice
  • Quarterly — the most common option for small businesses with GST turnover under $20 million
  • Annually — available if your GST turnover is under $75,000 (the voluntary registration threshold); you can opt into annual lodgement, but you still pay PAYG instalments quarterly

Your lodgement frequency is set when you register for GST, but you can apply to change it.

Due Dates

Missing BAS due dates results in penalties, so it is important to know when yours is due:

  • Quarterly BAS — due 28 days after the end of each quarter:
    • Q1 (July–September): due 28 October
    • Q2 (October–December): due 28 February
    • Q3 (January–March): due 28 April
    • Q4 (April–June): due 28 July
  • Monthly BAS — due 21 days after the end of each month
  • Annual BAS — due 31 October following the end of the financial year

If you lodge through a registered tax agent or BAS agent, you may be entitled to extended due dates. This is one reason many businesses use an agent.

How to Lodge

There are several ways to lodge your BAS:

  • Online via myGov or the ATO business portal — log in with your myGovID and lodge directly; this is the recommended method and results in faster processing
  • Through accounting software — Xero, MYOB, QuickBooks, and similar packages can prepare and lodge your BAS directly with the ATO; this reduces manual data entry errors
  • Through a registered BAS agent or tax agent — they handle preparation and lodgement on your behalf and can help you maximise your input tax credits
  • Paper forms — the ATO still accepts paper BAS forms, but this is the slowest option and not recommended

Common Mistakes

These are the mistakes the ATO sees most frequently:

  • Forgetting to include all income — all taxable sales must be included, even cash sales or payments received via apps
  • Claiming GST credits without a valid tax invoice — you must hold a tax invoice showing the supplier's ABN and the GST amount for any claim over $82.50
  • Mixing personal and business expenses — only business-related purchases can generate GST credits; personal expenses cannot be claimed
  • Getting the GST amount wrong — GST is 1/11th of the GST-inclusive price, not 10% of the GST-inclusive price; for example, a $110 purchase has $10 of GST (not $11)
  • Missing the due date — even if you cannot pay, lodge on time to avoid the failure-to-lodge penalty

Penalties for Late Lodgement

The ATO takes late lodgement seriously:

  • Failure-to-lodge penalty — for small businesses, this is $313 for each 28-day period (or part thereof) that the BAS is overdue, up to a maximum of $1,565
  • General interest charge (GIC) — applies to unpaid tax amounts from the due date until payment is made
  • Director penalty notices — if you run a company and fail to lodge or pay, directors can become personally liable for PAYG withholding amounts

If you are having difficulty paying, contact the ATO before the due date. The ATO can arrange payment plans and, in genuine hardship cases, may remit penalties. Do not ignore a BAS obligation — it rarely goes away on its own.

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