BAS and GST, prepared and lodged on time

Who it is for

• Sole traders and new businesses approaching the $75,000 GST turnover threshold
• GST-registered businesses lodging a quarterly or monthly BAS
• Employers reporting PAYG withholding from wages on their activity statement
• Business owners and investors who have been entered into PAYG instalments
• Non-profit organisations working out whether they have reached the $150,000 threshold
• Businesses with overdue activity statements or a BAS debt to sort out

GST and BAS, handled by your accountant

Calculating GST and preparing business activity statements are part of our bookkeeping service, alongside payroll, reconciliations and processing receipts, invoices and payments. Because your BAS is prepared from the books we keep, the figures you report line up with your accounts.

Ross Accounting Pty Ltd is a registered tax agent with the Tax Practitioners Board, registration number 21430015 (see the TPB public register). The TPB explains that providing or advertising BAS services for a fee while unregistered attracts significant civil penalties, so it is worth checking that whoever lodges your BAS is a registered tax or BAS agent.

When a business must register for GST

GST is a tax of 10% on most goods, services and other items sold or consumed in Australia. Under the ATO's current rules, registration is compulsory in these situations:

• GST turnover of $75,000 or more, or $150,000 or more for a non-profit organisation
• a new business that expects to reach the threshold in its first year
• taxi, limousine and ride-sourcing drivers, whatever their turnover
• income earned through the sharing economy or digital platforms, such as food delivery
• businesses that want to claim fuel tax credits

GST turnover is total business income, not profit, less the GST in your sales and certain other amounts. The ATO tests it two ways each month: current turnover (this month plus the previous 11) and projected turnover (this month plus the next 11). Once you reach the threshold you have 21 days to register, and you need an ABN first. Registering below the threshold is optional, but a business that chooses to register generally has to stay registered for at least 12 months.

A business that was required to register and did not may have to pay GST on sales made from the date registration became compulsory, even where GST was not added to the price, and penalties and interest may also apply. Backdating a GST registration is generally limited to 4 years. Our GST registration guide goes through the rules in more detail.

Keeping your books up to date each month is the simplest way to see the $75,000 GST threshold coming before you cross it.

What your BAS reports

Once registered for GST, a business lodges a business activity statement to report and pay its tax obligations. Depending on the business, a BAS can cover:

• GST: the GST included in your sales, less the GST credits on business purchases. If credits exceed the GST collected, you may receive a refund.
• PAYG withholding: the tax withheld from wages and other payments to employees and other payees. Under the ATO's current withholding cycles, withholders of $25,000 or less a year generally report and pay quarterly, those above $25,000 and up to $1 million monthly, and large withholders above $1 million pay electronically within 6 to 8 days of paying staff.
• PAYG instalments: regular prepayments of income tax on business and investment income, credited against your tax when your return is assessed.
• Other amounts, where they apply: fringe benefits tax instalments, luxury car tax, wine equalisation tax and fuel tax credits each have their own BAS labels.

To claim a GST credit, the purchase must be for your business and include GST, and you need a tax invoice for purchases over $82.50 including GST. Credits have to be claimed within a 4-year time limit. A BAS still has to be lodged, as a nil BAS, for a period with nothing to report.

Businesses with aggregated turnover under $10 million can generally choose to account for GST on a cash basis (reporting GST when payment is received or made) or a non-cash basis (generally when an invoice is issued or received, or when any payment is made, whichever comes first). The choice changes which BAS a sale or purchase lands in, and we can talk you through which suits your cash flow.

BAS due dates for 2026–27

How often you lodge depends on your GST turnover. According to the ATO, a business with GST turnover of $20 million or more, or one the ATO has directed to report monthly, must lodge monthly; others lodge quarterly and may choose monthly. Annual GST reporting is available to businesses voluntarily registered for GST with turnover under $75,000 ($150,000 for non-profits).

A monthly BAS is due on the 21st of the following month, so a July BAS is due on 21 August. Under the agent lodgment program, the December monthly BAS is due on 21 February instead of 21 January for businesses with turnover up to $10 million that report GST monthly and lodge electronically. An annual GST return lodged by the business itself is due on 31 October, or 28 February where no tax return is required; when a registered agent lodges it, it is due on the client's tax return due date.

When a due date falls on a weekend or a public holiday for a whole state or territory, the ATO allows lodgment and payment on the next business day. For example, 28 February 2027 is a Sunday and 1 March 2027 is Labour Day in Western Australia, so on the ATO's published holiday table the Q2 deadline moves to Tuesday 2 March 2027. The exact due date is always shown on your BAS. See our BAS lodgement due dates guide and the tax calendar.

The extra time under the agent lodgment program only applies to eligible activity statements lodged electronically, after the previous one was also lodged electronically.

PAYG instalments and what is changing

PAYG instalments are separate from PAYG withholding. Withholding is tax an employer takes out of wages; instalments are prepayments of your own income tax. Under the current entry thresholds, the ATO automatically enters an individual (including a sole trader) or a trust when all of these apply: instalment income of $4,000 or more in the latest return, tax payable of $1,000 or more on the latest assessment, and notional tax of $500 or more. A company or super fund is entered when its instalment income is $2 million or more, its notional tax is $500 or more, or it is the head company of a consolidated group. Most people pay quarterly.

Instalments can be varied, but if the varied rate or amount is less than 85% of the ATO's figure, general interest charge can apply to the shortfall. In the 2026–27 Budget (12 May 2026) the Government announced that from 1 July 2027 businesses will be able to vary instalments more readily and opt in to monthly instalments. The ATO states that these measures are not yet law. Our PAYG withholding and instalments guide explains both in more detail.

If you cannot lodge or pay on time

The ATO expects a BAS to be lodged and paid in full by the due date, and unpaid amounts attract the general interest charge. If you are having trouble, the ATO asks you or your registered tax professional to contact it before the due date. A business owing $200,000 or less may be able to set up a payment plan online, which needs an upfront payment, and interest keeps accruing until the debt is cleared.

Ross Accounting can bring overdue activity statements up to date and help with a payment arrangement. See managing tax debt and our ATO payment plans guide.

How it works

1. 1
   Check your GST position

   We look at your current and projected GST turnover, register you for GST if needed and set up the right reporting cycle and accounting method.

2. 2
   Keep the books

   Receipts, invoices and payments are processed and your accounts reconciled in Xero or MYOB, or you send documents through the MyAccountants app (accountant code "Ross").

3. 3
   Prepare your BAS

   We work out GST on sales and purchases, PAYG withholding from wages and any PAYG instalment, and go through the figures with you.

4. 4
   Lodge and pay

   We lodge your BAS as your registered tax agent and let you know the amount payable and the due date.

What to bring

• Access to your Xero or MYOB file, or your bank statements for the period
• Sales invoices and records of cash takings
• Tax invoices for business purchases over $82.50 including GST
• Payroll reports for the period, including wages paid and tax withheld
• Any PAYG instalment notice or activity statement the ATO has sent you
• Details of assets bought or sold, and any private use of business purchases