How does a BAS work for a sole trader in Australia?
By Invogo Team · Updated · 4 min read
A BAS (business activity statement) is the form you lodge with the ATO to report and pay the GST you collected, less the GST you paid on business costs. Most sole traders lodge it quarterly, due on 28 October, 28 February, 28 April and 28 July, and only need to fill in three GST boxes: G1, 1A and 1B.
What is a BAS and who has to lodge one?
A BAS is the ATO's regular summary of your GST and, if they apply to you, PAYG instalments and PAYG withholding. If you are registered for GST, you lodge one for every reporting period, even a period with no sales. If you are not registered, you don't lodge a BAS for GST. Not sure whether you need to register? Read when to register for GST.
How often do I lodge a BAS?
Most small businesses lodge quarterly. Businesses with a GST turnover under $20 million lodge quarterly unless the ATO has told them to report monthly.
| Quarter | Months | Due date |
|---|---|---|
| Q1 | July to September | 28 October |
| Q2 | October to December | 28 February |
| Q3 | January to March | 28 April |
| Q4 | April to June | 28 July |
If you lodge online, you may get an extra 2 weeks for Q1 to Q3. Q4 gets no extra time because its due date already includes one. Monthly reporters lodge and pay by the 21st of the month after the period ends. Check the ATO's due dates page for the current year, as dates can shift.
What do I actually put on a BAS?
Under the ATO's Simpler BAS method, which applies if your GST turnover is under $10 million, you report just three GST amounts:
- G1 (total sales): everything you sold in the period. Include taxable, GST-free and input-taxed sales. Enter 0 if you had none. Your G1 can be GST-inclusive or exclusive; you say which.
- 1A (GST on sales): the GST you owe the ATO for the period.
- 1B (GST on purchases): the GST credits you can claim back on business costs. You report the GST, not your total purchases.
You may also see T7 (your PAYG instalment amount, copied to 5A) and W1 (wages you pay workers). A sole trader with no employees usually has nothing at W1.
How do I work out what I owe?
Your GST payable is 1A minus 1B. Here is a worked example for one quarter:
- You invoiced $33,000 including GST. G1 = $33,000 and 1A = $3,000 (GST is one-eleventh of a GST-inclusive price).
- You paid $8,800 including GST for materials and fuel, with tax invoices. 1B = $800.
- You owe the ATO $3,000 - $800 = $2,200, plus any PAYG instalment.
If 1B is bigger than 1A, you get a refund. For the maths behind the numbers, see how to calculate GST.
Should I report GST on a cash or accruals basis?
If your turnover is under $10 million you can choose the cash method. On cash, you report GST in the period you are paid or you pay. On accruals (the non-cash method), you report it when you issue or receive the invoice. For a tradie who waits 30 days for payment, cash usually means you don't pay GST to the ATO on money you haven't received yet. Ask your accountant which suits you, because it is an ongoing choice rather than a one-off.
What do I need to claim GST credits?
You need to keep valid tax invoices from your suppliers for purchases to claim the GST in 1B. The same rules apply to the invoices you issue: see what a tax invoice must show. Without the invoice, you generally can't claim the credit.
What happens if I lodge late or can't pay?
The ATO can apply a failure to lodge penalty when a statement isn't lodged by its due date. It generally warns you first, and doesn't usually penalise a late BAS that ends up as a refund or nil result. If you can't pay in full, lodge on time anyway and contact the ATO about a payment plan. Lodging late and paying late are separate problems, and lodging on time keeps the first one off the table.
How can I make BAS time less painful?
Do the sums as you invoice, not in the last week before the due date. Invogo puts your ABN and GST on every invoice and quote automatically, so your sales figures are consistent and ready when the quarter closes, and the free plan covers 5 invoices or quotes a month. Tradies sending more can look at Invogo for tradies or start free. Many sole traders also set aside the GST from each payment into a separate account so the BAS bill never surprises them.
This is general information, not advice. Check with your accountant, a BAS agent or the ATO for your situation.
Frequently asked questions
Do I lodge a BAS if I had no sales?
Yes, if you are registered for GST you lodge for every period. Enter 0 at G1 if you had no sales.
Can I lodge my BAS myself?
Yes. Sole traders can lodge through the ATO's online services, or use a registered tax or BAS agent, who may get extra time to lodge.
What is the difference between a BAS and a tax return?
A BAS reports GST and instalments during the year. Your income tax return is lodged once a year and works out your actual income tax.
What if my BAS is due on a weekend?
Check the ATO due dates page for the current year, as the ATO lists the date it expects for each period.