What Is BAS Lodgement, and Why Does It Matter?
A Business Activity Statement (BAS) is the form you submit to the ATO each quarter to report your GST collected, GST paid, PAYG withholding on employee wages, and other tax obligations. For most small businesses, getting this wrong, or late, has real financial consequences.
Late lodgement penalties
The ATO charges $330 per 28-day period your BAS is overdue, up to $1,650. That's money straight out of your pocket for an entirely preventable problem.
GST coding errors
Incorrectly coded transactions mean you either overpay GST (money left on the table) or underpay it (triggering ATO audits and back-payments with interest).
Legal lodgement requirement
If anyone other than you is lodging your BAS, they must be a registered BAS agent under Australian law. Using an unregistered person exposes both of you to penalties.
What's Included in Our BAS Lodgement Service
- Full transaction review every transaction checked for correct GST coding before lodgement
- BAS preparation GST, PAYG withholding, PAYG instalments, and fuel tax credits where applicable
- ATO lodgement submitted directly to the ATO via our registered agent portal
- Lodgement confirmation you receive confirmation once lodged with the amount payable or refundable
- Agent extension benefit registered BAS agents receive an additional 4-week extension on quarterly deadlines
- ATO correspondence we handle any follow-up queries from the ATO on your behalf
BAS and Activity Statement Due Dates
| Quarter | Period | Standard Due Date | Agent Extension |
|---|---|---|---|
| Q1 | Jul, Sep | 28 October | 25 November |
| Q2 | Oct, Dec | 28 February | 25 March |
| Q3 | Jan, Mar | 28 April | 26 May |
| Q4 | Apr, Jun | 28 July | 25 August |
Agent extension dates are approximate and subject to ATO confirmation each year.
What Actually Goes in a BAS
A business activity statement (BAS) is the form you use to report and pay several obligations to the ATO at once. Depending on your registrations, it can include:
- GST (labels G1, 1A and 1B). G1 is your total sales, 1A is the GST you collected on sales, and 1B is the GST you paid on purchases. You pay the difference, or are refunded it.
- PAYG withholding (W1 and W2). W1 is the total wages you paid, W2 is the tax you withheld from your staff and send to the ATO on their behalf.
- PAYG instalments (T7). Pre-payments towards your own income tax, worked out by the ATO from your last return.
- Other items where they apply, such as fuel tax credits, luxury car tax or wine equalisation tax.
Most small businesses only deal with GST and PAYG withholding, but getting even those labels right depends entirely on your bookkeeping being accurate through the quarter. A BAS is only ever as correct as the file it is prepared from.
How to Lodge Your BAS
There are three ways to lodge a business activity statement:
- Yourself, through ATO online services. Via myGov for sole traders, or ATO Online services for business with a myGovID. Workable, but you are on the standard due dates with no extra time.
- Through your accounting software. Xero can prepare and lodge the BAS directly once it is set up correctly, which reduces manual re-keying.
- Through a registered BAS agent. A registered BAS service provider prepares and lodges on your behalf, and you receive the BAS agent concession dates, which give you roughly an extra four weeks on most quarterly deadlines. You also get a second set of eyes checking the numbers before anything is lodged.
Payment is separate from lodgement. You can pay by BPAY, direct debit or bank transfer using the payment reference number on your BAS. Note that from 1 December 2026 the ATO no longer accepts credit card payments for tax and BAS, so if you used a card, read what is changing and how to plan for it.
GST, Cash Versus Accruals, and Your BAS
If your business is registered for GST (compulsory once your turnover reaches $75,000, or $150,000 for a not-for-profit), GST is usually the biggest part of your BAS. Two things decide whether your GST is right. The first is your accounting method: on a cash basis you account for GST when money actually moves, and on an accruals basis when you invoice or are invoiced. The method is set in your software and must match what you told the ATO, or every BAS will be out.
The second is GST coding. Every transaction has to be coded correctly as GST on income, GST on expenses, GST free or BAS excluded. The classic errors are claiming GST on things that are GST free, like most basic food, certain health services and bank fees, or forgetting GST on taxable sales. Those errors flow straight onto the BAS, which is why clean bookkeeping during the quarter matters more than anything you do at lodgement time.
What Happens if You Lodge or Pay Late
Lodging or paying a BAS late has two separate consequences. A failure to lodge on time penalty is charged in penalty units and increases the longer the statement is outstanding, and the ATO applies a general interest charge on any unpaid amount. The interest compounds daily, so a small debt grows faster than people expect.
If you cannot pay in full, the worst move is to not lodge. Lodge on time even if you cannot pay, because that avoids the failure-to-lodge penalty, then arrange an ATO payment plan for the amount owing. A payment plan is almost always cheaper than the interest and penalties of simply ignoring it. If you have fallen behind on several quarters, catch-up bookkeeping and a single conversation with the ATO usually sorts it out faster than owners fear.
Common BAS Mistakes We See
- Claiming GST on GST-free or input-taxed items such as basic food, certain health services, bank fees and residential rent.
- Mismatched accounting method, where the software is on accruals but the ATO registration says cash, or the reverse.
- Private expenses claimed in full when only the business-use portion is deductible and GST-claimable.
- Wages at W1 not matching Single Touch Payroll, which the ATO now cross-checks automatically.
- Lodging from an unreconciled file, so the figures are an estimate rather than the real position.
Every one of these is avoidable with accurate books and a review before lodgement, which is exactly what a registered BAS agent is for.
Frequently Asked Questions, BAS Lodgement
What is a BAS and when does it need to be lodged?
A Business Activity Statement reports your GST, PAYG withholding, and other obligations to the ATO. Most small businesses lodge quarterly. Deadlines: Q1 due 28 Oct, Q2 due 28 Feb, Q3 due 28 Apr, Q4 due 28 Jul. Registered BAS agents receive a 4-week extension on all quarterly deadlines.
Do I need a registered BAS agent?
If someone other than you is preparing and lodging your BAS, yes, they must be a registered BAS agent under Australian law. Using an unregistered person is illegal. True Tally is a registered BAS provider with the Tax Practitioners Board.
What happens if I lodge my BAS late?
The ATO charges $330 for every 28-day period your BAS is overdue, up to $1,650. They may also issue a default assessment estimating your liability, often higher than actual. A registered BAS agent ensures this never happens. If a debt has already built up, see our guide to ATO payment plans for small business.
What is the difference between a BAS agent and a tax agent?
A BAS agent handles GST and BAS obligations. A tax agent does this plus income tax returns. For BAS lodgement purposes, a registered BAS agent is sufficient and more cost-effective than a tax agent for this specific service.
What is a business activity statement (BAS)?
A BAS is the form you use to report and pay GST, PAYG withholding (the tax you hold from staff wages), PAYG income tax instalments, and some other taxes to the ATO, usually each quarter. It is also called an activity statement.
When are BAS and activity statement due dates?
Standard quarterly dates are 28 October, 28 February, 28 April and 28 July, with extra time when you lodge through a registered BAS agent. Monthly activity statements are generally due on the 21st of the following month. BAS due dates, activity statement due dates and BAS statement due dates all mean the same thing.
Do BAS agents get extra time to lodge?
Yes. Registered BAS agents receive concession dates that give roughly an extra four weeks on most quarterly deadlines, which is one reason lodging through an agent is worthwhile beyond the accuracy check.
Is your current bookkeeper adding real value?
A few honest questions worth asking about whoever keeps your books:
- Bank reconciliation is your bank account in Xero actually checked against your bank statement every month, not just left to auto-match?
- Speed that adds value are your accounts reconciled quickly enough that your management reports are current and worth acting on, not weeks behind?
- On-time compliance is your Single Touch Payroll being filed on time, every pay run?
Cheaper service does not always mean better service. We invest in continuing professional education so we deliver genuine value, not just the lowest price. As we get to know your business for the long term, we review your expense-saving opportunities and recommend better setups and cost-effective ways to cut your overheads. Honest, candid, and on your side.
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