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BAS explained for Australian business

If you are registered for GST in Australia, you lodge a Business Activity Statement. Here is what a BAS covers, who has to lodge one, when it is due, and how to get it right.

Written by the Countova team · Updated August 2026 · General guidance, not tax advice

What a BAS is

A Business Activity Statement, or BAS, is the form you use to report and pay several taxes to the Australian Taxation Office in one go. For most small businesses it is mainly about GST, but it can also cover pay-as-you-go amounts and a few other obligations. Think of it as a regular summary of the tax you have collected and the tax you owe.

What a BAS covers

• GST you collected on sales, and GST credits you can claim on purchases.
• PAYG withholding, the tax you held back from employee wages.
• PAYG instalments, prepayments towards your own income tax.
• Other items where they apply, such as fuel tax credits or wine equalisation tax.

Do you need to lodge one?

You must register for GST, and therefore lodge a BAS, once your business turnover reaches $75,000 a year (or $150,000 for a not-for-profit). Taxi, rideshare and some other operators must register regardless of turnover. Once registered, the ATO issues your BAS automatically for each period. GST in Australia is 10 percent.

How often you lodge

Most small businesses lodge quarterly. Larger businesses (generally $20 million or more in turnover) lodge monthly, and some very small operators report annually. The standard quarterly due dates are:

If you lodge through a registered BAS or tax agent, you often get a few extra weeks. If a due date falls on a weekend or public holiday, it moves to the next business day.

Cash or accruals?

Like New Zealand, Australia lets smaller businesses account for GST on a cash basis, where GST is counted when money is received or paid. The alternative is accruals, where it is counted from the invoice date. Cash is generally easier on cash flow, and most businesses under $10 million turnover can choose it.

How to lodge a BAS

1. Online through the ATO, using myGov linked to the ATO, or the Business Portal for companies.
2. Through a registered BAS or tax agent, who can lodge on your behalf and usually gets extended dates.
3. Straight from your accounting software using Standard Business Reporting, so the figures go from your books to the ATO without re-keying.

Common BAS mistakes

• Claiming GST credits on purchases that had no GST, like bank fees or GST-free food.
• Mixing up the GST-free and input-taxed categories.
• Forgetting PAYG withholding for employees.
• Lodging late, which can bring failure-to-lodge penalties and interest.

How software makes BAS painless

When your sales, purchases and payroll all sit on one platform, your BAS is assembled as you trade. Countova applies 10 percent GST correctly across your transactions, tracks PAYG withholding from payroll, and prepares the BAS figures from your live data so there is nothing to reconstruct at quarter end. You check it, then lodge. When your numbers are always current, the deadline stops being a scramble.