BAS Lodgement Guide for Australian Sole Traders

What Is a BAS?

A Business Activity Statement (BAS) is a form submitted to the Australian Taxation Office (ATO) that reports your business's tax obligations for a given period. Most commonly, it covers:

GST — the 10% Goods and Services Tax you've collected from customers, minus the GST you've paid on business expenses (input tax credits)
PAYG withholding — tax withheld from employee wages
PAYG instalments — prepayments of your own income tax

If you're a sole trader registered for GST, you'll need to lodge a BAS — either monthly, quarterly, or annually depending on your turnover and ATO instructions.

Do You Need to Register for GST?

You must register for GST if your annual turnover is $75,000 or more (or $150,000 for non-profit bodies). Ride-share and taxi drivers must register regardless of turnover. Once registered, you must lodge a BAS.

Even if you're under the threshold, voluntary registration can make sense if you incur significant GST on your business expenses — it lets you claim those back as input tax credits.

BAS Lodgement Frequency

The ATO assigns your lodgement frequency:

Monthly: If your annual turnover exceeds $20 million
Quarterly: Most small businesses (turnover $75K–$20M)
Annual: If the ATO has granted you annual lodgement (turnover under $75K and voluntarily registered)

Quarterly lodgement dates are typically the 28th of the month following the quarter-end (October 28, February 28, April 28, July 28). If your BAS is prepared by a registered tax agent, you may get an extended due date.

What Goes on a Quarterly BAS?

GST Section

You report:

G1 — Total sales: All sales including GST-free and input-taxed sales
G2 — Export sales: If you export goods or services
G3 — Other GST-free sales: Fresh food, basic health services, etc.
G10 — Capital purchases: Business assets you purchased
G11 — Other purchases: All other business expenses

The ATO calculates your net GST from these figures (GST collected minus input tax credits).

PAYG Withholding Section

If you have employees, report the total withholding for the quarter at W1 and W2.

Common BAS Mistakes to Avoid

Claiming GST on non-GST purchases: Some expenses don't include GST — bank fees, wages, insurance (some), and purchases from unregistered suppliers. Claiming input tax credits on these is an error.

Missing the due date: Late BAS lodgement attracts Failure to Lodge (FTL) penalties. These accumulate weekly. Getting into a habit of lodging on time is far less painful than paying penalties.

Incorrect GST codes in Xero or MYOB: If your accounting software has incorrect tax codes set up, your BAS figures will be wrong from the start. A chart of accounts review is worthwhile if you're not sure.

Not keeping records: The ATO requires you to keep records for 5 years. Every invoice, receipt, and bank statement is evidence. Cloud accounting software like Xero makes this much easier to maintain.

Using a Tax Agent for BAS

A registered tax agent (or BAS agent) can lodge on your behalf and typically gets an extended due date from the ATO — often an additional month. For sole traders with complex GST situations or heavy transaction volumes, the cost of a BAS agent is usually worth it.

Books & Beyond's Australian team is ATO-registered and handles BAS lodgement as part of our bookkeeping and tax services. If your BAS is overdue or you want a clean process going forward, get in touch.