Getting your books ready for BAS is not something that happens at the end of the quarter. It happens throughout the quarter — transaction by transaction, week by week. For Melbourne small businesses that leave their bookkeeping until October, BAS time becomes a scramble. For those that maintain their records consistently, it is a straightforward review.
Q1 BAS covers July, August and September 2026. The lodgement deadline for self-lodgers is 28 October 2026. If your books are not current, accurate and properly reconciled before BAS preparation begins, the figures your BAS agent or accountant works from will not reflect what actually happened in your business.
This guide explains what BAS-ready books look like, what needs to be done before preparation can begin, and how to avoid the last-minute October scramble that affects thousands of Melbourne businesses every quarter.
Table of contentsA Business Activity Statement (BAS) is the form Australian businesses use to report and pay their GST, PAYG withholding, PAYG instalments, and other tax obligations to the ATO.
For most Melbourne small businesses, BAS is lodged quarterly. The Q1 period covers July, August and September — and the self-lodgement deadline is 28 October 2026.
The critical point is this: your BAS figures come directly from your bookkeeping records. A BAS is not calculated independently — it is a summary of what your accounting software already shows. If transactions are missing, uncategorised or incorrectly coded, those errors flow directly into your BAS figures.
The ATO uses BAS data to identify discrepancies, cross-reference income against bank data and detect GST errors. Clean, accurate books reduce that risk entirely.
⚠️ Late lodgement penalties start at $313 for small businesses and increase with each 28-day period the lodgement remains outstanding. General interest charges also apply to any unpaid amounts from the due date.
Before BAS preparation can begin, your books need to meet a specific standard. The following checklist covers every area that affects your BAS figures.
Every income and expense transaction from 1 July to 30 September needs to be entered into your accounting software and assigned to the correct category. This includes:
The most common GST error is claiming credits on GST-free purchases such as basic food, certain medical supplies or financial services. These need to be identified at the transaction level, not corrected at BAS time.
Every bank account, credit card and loan account connected to the business needs to be reconciled to 30 September. Reconciliation means every transaction in your bank feed is matched to a corresponding record in your accounting software — with no unmatched items outstanding.
Unreconciled transactions are one of the most common causes of BAS inaccuracies. A payment that cleared the bank but was never matched, or an invoice that was entered twice — these discrepancies affect your GST totals directly.
💡 Tip: Reconcile each month as it closes — July in early August, August in early September, September in early October. Leaving three months of reconciliation until October significantly increases the time and risk involved.
Every sale made during the quarter needs a corresponding invoice in your accounting software, correctly dated and with the right GST treatment. This includes:
Your GST on sales — the amount collected from customers and owed to the ATO — comes from these invoices. Missing invoices means understated GST liability, which creates ATO risk if your BAS is later reviewed.
Every bill received from a supplier during the quarter needs to be entered with the correct date, amount and GST coding. This determines your GST credits — the amount you can claim back from the ATO.
Commonly missed items include:
If you employ staff, your BAS includes a PAYG withholding section — the tax withheld from employee wages that must be paid to the ATO. This figure must match your payroll records exactly.
With Payday Super now live from 1 July 2026, payroll records are more complex — super is paid with every payroll run rather than quarterly. Before BAS preparation begins, confirm:
Business credit cards, lines of credit and loan accounts all need to be reconciled — not just bank accounts. Expenses paid on a business credit card that are not entered into your accounting software do not appear in your GST calculations, meaning you miss credits you are entitled to claim.
Before your records go to BAS preparation, review and resolve:
⚠️ The ATO requires tax invoices for all purchases over $82.50 (GST-inclusive) before a GST credit can be claimed. If the receipt is missing, the credit cannot be included in your BAS.
The following errors appear consistently in Melbourne small business bookkeeping and directly affect BAS accuracy:
| Error | Impact on BAS | How to avoid it |
|---|---|---|
| GST claimed on GST-free purchases | Overstated GST credits | Check GST treatment at transaction entry, not at BAS time |
| Income invoices missing from the system | Understated GST on sales | Issue and record invoices the same day work is completed |
| Bank accounts not reconciled | Unreliable GST totals | Reconcile each bank account at the end of every month |
| PAYG withholding not matching STP | Incorrect PAYG figures in BAS | Reconcile payroll to STP before BAS preparation begins |
| Supplier bills entered in the wrong period | GST credits in the wrong quarter | Enter bills with the invoice date, not the payment date |
| Mixed personal and business expenses | Incorrect GST claimed | Use a dedicated business account for all business transactions |
| Tax invoices missing for purchases over $82.50 | GST credits cannot be claimed | Attach receipts to transactions in your accounting software as they occur |
The following timeline gives you a practical schedule for getting your books BAS-ready before 28 October without the last-minute pressure:
| Date | Action | Why |
|---|---|---|
| 1 July | Begin entering transactions weekly from the start of the quarter | Weekly entry prevents a three-month backlog building up |
| End of July | Reconcile all accounts for July — bank, credit card, loans | Resolve unmatched items before August adds more |
| End of August | Reconcile August — review accounts receivable aging | Chase any July invoices still outstanding before September closes |
| 30 September | Quarter ends — enter any remaining September transactions promptly | September entries should be complete by the second week of October |
| 1–14 October | Complete September reconciliation — resolve all outstanding items | This is your catch-up window — do not leave it until the final week |
| 14–21 October | BAS preparation — review GST figures, PAYG, and any other BAS items | With clean books, this should take hours, not days |
| 28 October | BAS lodgement deadline for self-lodgers | Contributions must be received by the fund within seven business days of payday |
When your bookkeeping is maintained properly throughout the quarter, the difference at BAS time is significant.
With clean, current records:
When books are not current, BAS preparation requires reconstruction — working backwards through months of transactions to piece together what actually happened. This takes longer, costs more if a professional is involved, and produces results that carry more risk.
💡 Clean books throughout the quarter also improve your business beyond BAS. Accurate monthly P&L reports, better cash flow visibility, and a smoother year-end process all follow from the same discipline that makes BAS preparation straightforward.
Procura Global Accounting provides outsourced bookkeeping services for Melbourne small businesses — maintaining accurate, current and properly categorised financial records throughout every quarter.
Our bookkeeping service is designed so that when BAS preparation time arrives, your records are already in the right shape. We handle:
We prepare BAS-ready records — we do not lodge BAS. Lodgement is handled by your registered BAS agent or tax agent. Our role is to ensure the records they receive are accurate, complete and properly categorised so their job is straightforward and your lodgement reflects the reality of your business.
📞 Want your books BAS-ready every quarter without the scramble? Contact Procura Global at procuraglobal.net or call +61 411 136 046 to discuss our outsourced bookkeeping service for Melbourne businesses.
What does BAS-ready mean?
BAS-ready means your financial records are accurate, complete and properly categorised for the quarter — so that whoever prepares your BAS has reliable figures to work from without needing to reconstruct or fix your books first.
Does Procura Global lodge BAS?
No. Procura Global prepares BAS-ready bookkeeping records. BAS lodgement is a separate function that must be performed by a registered BAS agent or tax agent. Our role is to ensure your records are accurate and complete before they go to lodgement.
How often should I reconcile my bank accounts?
Monthly, at a minimum. Reconciling at the end of each month means errors are caught early and nothing builds up. Quarterly reconciliation is too infrequent — three months of unmatched transactions are significantly harder and more time-consuming to resolve than one month.
What is the Q1 BAS deadline for 2026–27?
The Q1 BAS (covering July, August and September 2026) is due 28 October 2026 for self-lodgers. If you lodge through a registered BAS agent, an extended deadline of 25 November 2026 typically applies.
What records do I need to keep for BAS?
The ATO requires you to keep records for five years. This includes tax invoices for all purchases over $82.50 (GST-inclusive), bank statements, supplier bills, sales invoices and payroll records. Digital copies stored in your accounting software are acceptable.
Can I claim GST on all business expenses?
No. GST can only be claimed on purchases that include GST. GST-free items (such as fresh food, basic financial services and certain health services) and input-taxed items (such as residential rent) do not carry GST and cannot be claimed. Incorrect GST claims are one of the most common BAS errors.
What happens if I miss the BAS deadline?
The ATO applies a failure-to-lodge penalty that starts at $313 for small businesses and increases with each additional 28-day period the lodgement remains outstanding. General interest charges also apply to any tax owing from the due date.
How does outsourced bookkeeping help with BAS?
Outsourced bookkeeping ensures your records are entered, categorised and reconciled throughout the quarter — not just at BAS time. When BAS preparation begins, your records are already in the right state. This reduces preparation time, reduces the risk of errors and makes the process more straightforward for whoever is lodging your BAS.
The businesses that find BAS straightforward every quarter are not the ones with the fastest accountants at lodgement time. They are the ones with the most consistent bookkeeping throughout the quarter. Start July correctly, and October takes care of itself.
Need support getting your books BAS-ready? Contact Procura Global to discuss outsourced bookkeeping and BAS preparation support for your Melbourne business.
Procura Global Accounting provides trusted accounting, tax, and advisory services that simplify finances, ensure compliance, and support confident business growth.
