By Joshua Occhino, Co-founder, Ezyiah
Short answer: A business activity statement (BAS) is the form GST-registered businesses use to report and pay GST and other business taxes to the ATO, including PAYG withholding and PAYG instalments. If you're registered for GST you need to lodge one, even when there's nothing to report. Most smaller businesses lodge quarterly, with due dates shown on the statement.
What is a BAS?
According to the ATO, if you are a business registered for GST you need to lodge a business activity statement (BAS). Your BAS helps you report and pay:
- goods and services tax (GST)
- pay as you go (PAYG) instalments
- PAYG withholding tax
- other taxes.
"Other taxes" can include fringe benefits tax (FBT) instalments, luxury car tax, wine equalisation tax and fuel tax credits, listed on the ATO's BAS hub. What appears on your statement depends on your registrations.
If you want the GST rules behind the figures, start with What is GST in Australia?.
Who has to lodge a BAS?
The ATO's starting point is straightforward: if you are registered for GST, you need to lodge a BAS. It also says you automatically receive a BAS if you're registered for GST. Having an ABN on its own is not the trigger.
Some people receive a quarterly instalment notice instead of a BAS. The ATO says that happens if you report and pay GST or PAYG instalments quarterly, you pay the instalment amount it has advised, and you have no other reporting requirements. If you just pay the amount shown, you generally don't need to lodge the notice unless you want to vary it.
What do you report on a BAS?
The common labels are:
| Area | What the ATO uses it for |
|---|---|
| GST | Sales, purchases and the GST you collected or can claim, including labels such as G1 and 1A / 1B |
| PAYG withholding | Tax you withheld from payments to employees or other payees |
| PAYG instalments | Instalments towards your own income tax |
| FBT instalments | Instalments of fringe benefits tax, if that applies |
| Luxury car tax and wine equalisation tax | Only if those taxes apply to what you sell |
| Fuel tax credits | Credits you claim for eligible fuel use |
You complete the labels that apply to you. The ATO expects you to keep most business records for 5 years and suggests using accounting software to produce tax invoices and GST reports at BAS time. See BAS record-keeping requirements.
How often do you lodge a BAS?
- Monthly, if your GST turnover is $20 million or more, or if the ATO has directed you to report monthly. You can also choose to report monthly if your turnover is under $20 million.
- Quarterly, if your GST turnover is less than $20 million and the ATO hasn't told you to report monthly. This is the cycle most small businesses are on.
- Annually, if you are voluntarily registered for GST and your GST turnover is under $75,000 ($150,000 for not-for-profit organisations).
When is a BAS due?
The due date for lodging and paying is displayed on your BAS. If that date falls on a weekend or public holiday, you have until the next business day.
For quarterly reporters, the standard due dates are:
| Quarter | Period | Due date |
|---|---|---|
| 1 | July, August and September | 28 October |
| 2 | October, November and December | 28 February |
| 3 | January, February and March | 28 April |
| 4 | April, May and June | 28 July |
Monthly BAS are due on the 21st of the following month (a July BAS is due 21 August).
If you lodge online, you may be eligible for an extra 2 weeks to lodge and pay a quarterly BAS. Extra time may also apply if you lodge through a registered tax or BAS agent. That later due date does not apply to quarter 2, because 28 February already includes a one-month extension.
For the full 2026-27 calendar, including online, agent and annual GST dates, see BAS due dates 2026-27.
How do you lodge a BAS?
The ATO lists three lodgement options: lodge online, lodge through a registered tax or BAS agent, or lodge by mail using the original paper BAS it sent you. You can't lodge a sample form, because each BAS is unique to you.
Online options include Online services for individuals and sole traders (via myGov), Online services for business, and Standard Business Reporting (SBR) enabled software. If your GST turnover is $20 million or more, you must lodge online.
If you cannot lodge or pay on time, contact the ATO or your registered tax professional before the due date. Paying late can attract the general interest charge.
What if you have nothing to report?
You still need to lodge. The ATO is explicit: even if you have nothing to report for the period, you still need to lodge your BAS as "nil" by the due date.
You can prepare a nil BAS online by selecting Prepare, then Prepare as nil, or lodge a nil BAS by phone on 13 72 26. The ATO lists some exceptions, including annual GST returns. The practical detail, including what happens if a nil BAS is missed, is in Nil BAS lodgement.
A worked example: one quarter for a sole-trader plumber
This is an illustrative example, not a customer story.
Alex is a GST-registered sole-trader plumber. Alex's GST turnover is well under $10 million, so Alex can account for GST on a cash basis and reports quarterly. On a cash basis, GST is reported in the period money is actually received or paid.
For July to September, Alex's business account shows:
| Item | Amount incl. GST | GST (÷ 11) |
|---|---|---|
| Customer payments received for taxable plumbing work | $22,000 | $2,000 GST collected |
| Business purchases paid, all with valid tax invoices or receipts | $5,500 | $500 GST credits |
| Net GST payable on the BAS | $1,500 |
Alex has no employees, so there is no PAYG withholding to report. The July-September BAS is due 28 October if Alex lodges it without using the online or agent extra time.
GST in a GST-inclusive price is one-eleventh of the total. To claim a GST credit on a purchase that costs more than $82.50 including GST, Alex must hold a tax invoice. To check a figure, use our free GST calculator.
Can software lodge my BAS for me?
Software can prepare the figures from your reconciled transactions. Lodging is a separate step.
In Australia, completing or confirming activity statement figures for a fee can be a BAS service. The sensible workflow is that software prepares the BAS from your reconciled books, then your registered tax or BAS agent reviews the GST coding and figures and lodges, or tells you exactly what to lodge.
For who can lodge, read Can a bookkeeper lodge BAS in Australia?.
Ezyiah prepares a cash-basis BAS, including Extended BAS, from your reconciled bank transactions. Your accountant or BAS agent still checks the figures before anything is lodged. See how Ezyiah takes books from bank feed to BAS.
FAQ
Is a BAS the same as my tax return?
No. A BAS reports GST and certain other business taxes during the year, usually monthly or quarterly. Your income tax return is a separate lodgement that covers your annual income tax.
Do I need to lodge a BAS if I didn't trade this quarter?
Yes, if you have a BAS to lodge. The ATO says you still need to lodge it as nil by the due date, even when you have nothing to report.
Can I lodge a BAS myself?
Yes. You can lodge online, by mail, or through a registered tax or BAS agent. If your GST turnover is $20 million or more, you must lodge online.
What's the difference between a BAS and an instalment notice?
A BAS must be completed and lodged. An instalment notice is issued when you pay an ATO-advised GST or PAYG instalment and have no other reporting requirements. If you just pay the amount shown, you generally don't need to lodge it unless you want to vary it.
When is the next quarterly BAS due?
The standard dates are 28 October, 28 February, 28 April and 28 July. Check the date on your own BAS, and see our BAS due dates for online and agent dates.
Get the figures ready before the due date
Ezyiah connects to your bank, codes each transaction and its GST treatment, matches receipts and invoices, and prepares your BAS from the reconciled data. Your accountant then reviews and approves it before lodgement. Plans for businesses start from $79 a month billed yearly, and from $299 a month billed yearly for accounting firms. Prices are in Australian dollars and include GST. See how the AI bookkeeper for business owners works, or start your free trial.
This article is general information, not tax advice. Check your own situation with a registered tax or BAS agent.
Sources
- ATO, Business activity statements (BAS), accessed 7 November 2026
- ATO, How to lodge your BAS, accessed 7 November 2026 (last updated 14 September 2026)
- ATO, Due dates for lodging and paying your BAS, accessed 7 November 2026 (last updated 17 September 2026)
- ATO, Instalment notices for GST and PAYG instalments, accessed 7 November 2026
- ATO, When you can claim a GST credit, accessed 7 November 2026
- ATO, Tax invoices, accessed 7 November 2026
- ATO, Choosing an accounting method for GST, accessed 7 November 2026
- ATO, Accounting for GST in your business, accessed 7 November 2026
- ATO, Overview of record-keeping rules for business, accessed 7 November 2026
- Tax Practitioners Board, BAS services, accessed 7 November 2026
- Ezyiah, Changelog, accessed 7 November 2026
- Ezyiah, Pricing and pricing for businesses, accessed 7 November 2026
