A BAS deadline should not be the first time you look closely at your numbers for the quarter. When receipts are missing, bank feeds are unreconciled and payroll has been left until the end, preparing a BAS becomes a stressful clean-up job. Knowing how to prepare BAS properly means building a simple routine that keeps your records current and gives you confidence in what you lodge.
For many small businesses, the hard part is not entering figures into the BAS. It is making sure those figures are complete, correctly coded and supported by records. A tidy process also gives you more than compliance – it shows how sales, expenses, wages and cash flow are tracking.
Start by confirming what your BAS needs to report
Your business activity statement reports the taxes relevant to your registration and business structure. For many small businesses, this includes GST. It may also include PAYG withholding if you employ staff, and PAYG instalments if the ATO requires you to pay income tax progressively.
The labels and reporting method on one BAS will not always match another. A sole trader with no employees may have a relatively straightforward GST statement. A growing trade business with staff, contractors and regular asset purchases will have more moving parts. Start with the actual BAS or ATO notice for the period rather than relying on last quarter’s assumptions.
Before doing any calculations, confirm the reporting period and due date. Businesses commonly report monthly, quarterly or annually, depending on their GST registration and turnover. If you use a tax or BAS agent, the lodgement date may differ from the standard due date, but the work still needs to be ready in good time.
Keep records up to date before you prepare BAS
The best BAS preparation happens throughout the quarter. Set aside regular time – weekly or fortnightly is usually enough for a small operator – to bring your records up to date. Waiting until the final week makes it easier to overlook cash purchases, duplicate bills or incorrectly categorised transactions.
Your accounting file should include all sales invoices, supplier bills, bank transactions, loan repayments, card payments and cash expenses for the period. Keep tax invoices and receipts for business purchases, particularly where GST is being claimed. A bank transaction alone may show that money left the account, but it does not always prove the nature of the expense or whether GST applies.
For businesses using Xero, bank feeds and receipt capture can reduce manual work, but they do not replace review. Rules can apply the wrong coding when a supplier changes what they charge for, and transactions can be matched to the wrong invoice. Automation is useful when the system is set up well and someone checks the result.
Reconcile every account, not just the main bank account
Reconciliation is where BAS figures become reliable. Reconcile your bank accounts to the statement balance as at the end of the reporting period. Then do the same for business credit cards, payment platforms, clearing accounts and finance accounts that run through the accounting file.
A common mistake is to reconcile the operating account but leave Stripe, Square, PayPal or a merchant terminal account unresolved. Sales can be recorded on the day a customer pays, while the cash reaches your bank days later after fees are deducted. If those accounts are not reconciled, income or expenses may be missed, duplicated or reported in the wrong period.
Check that outstanding customer invoices and supplier bills are genuine as well. Old invoices may need follow-up, credit notes or write-offs. Bills that were paid personally by the business owner should still be recorded correctly, rather than disappearing from the business records.
Check GST coding before relying on the BAS report
Once accounts are reconciled, review the GST treatment behind the report. The BAS report is only as accurate as the coding used to create it.
Look closely at larger or unusual transactions. Vehicle purchases, equipment, deposits, insurance, bank charges, imported goods, overseas software subscriptions and owner drawings can all require different treatment. Not every business expense includes GST, and not every payment is deductible. Similarly, not all income is subject to GST.
Make sure private or mixed-use expenses have been treated appropriately. For example, a mobile bill used partly for business may need an adjustment, while personal spending paid from the business account should not be coded as a business expense simply to make the reconciliation balance.
If you are registered for GST on a cash basis, you generally report GST when money is received or paid. Under the accruals method, GST is generally reported when invoices or bills are issued or received. This distinction matters around quarter end. Do not assume a payment date tells the whole story without checking your accounting basis.
Review sales, purchases and payroll together
Before you lodge, review the totals as a business owner, not just as a data-entry exercise. Does the sales figure broadly make sense for the quarter? If turnover is noticeably higher or lower than expected, find out why. It may be a genuine change in trading, but it could also be an invoice coded incorrectly, a duplicated sales import or income posted to the wrong account.
Do the same with purchases. Large fluctuations may be completely reasonable if you bought stock, tools or equipment, but they should be explainable. A quick comparison with the prior quarter can reveal errors that are difficult to spot line by line.
If you have employees, reconcile payroll before finalising PAYG withholding. Check that wages, allowances, deductions and withholding in your payroll system agree with the amounts posted to your accounts. Ensure payroll reporting obligations have been handled through Single Touch Payroll and that superannuation payments are being tracked separately. Super is not generally reported as a BAS label, but missed payments can create a bigger compliance issue later.
Complete the BAS from verified figures
With reconciliations and GST coding reviewed, run your BAS or activity statement report for the exact reporting period. Transfer the figures carefully to the relevant BAS labels, or use your accounting software’s lodgement workflow if it is correctly connected and reviewed.
Do not rush past a figure simply because the software has populated it. Check the GST collected on sales against the sales total and check GST credits against purchases. Where your BAS includes PAYG withholding or instalments, make sure those amounts have been checked against payroll records and the ATO notice.
Save a copy of the reports used to prepare the BAS, along with supporting documents and any adjustment notes. This creates a clear record of how the figures were reached. It also makes future questions, amendments or year-end tax work much easier.
Lodge, pay and keep the next quarter moving
Once you are satisfied the BAS is correct, lodge it by the applicable due date and arrange payment if there is an amount owing. Lodging on time matters even when cash flow is tight. If payment will be difficult, deal with it early rather than ignoring the obligation.
After lodgement, record the BAS payment or refund correctly in your accounting file. Then begin the next reporting period with the same habits: reconcile regularly, capture documents as they arise and review anything unusual before it becomes old news.
When it makes sense to get BAS support
Some business owners can manage their BAS internally, particularly where transactions are simple and records are kept up to date. Others benefit from support once payroll, multiple payment platforms, contractors, stock, vehicle costs or rapid growth add complexity. The right approach depends on the volume of transactions and how confident you are in the coding behind the numbers.
A registered BAS agent or tax agent can help review records, prepare and lodge the statement, and explain what the figures mean for your cash flow. For local operators across Mount Barker and the Adelaide Hills, practical support is often most valuable when it also improves the day-to-day system, not just the lodgement at the end of the quarter.
A well-prepared BAS is not about scrambling to meet a date. It is the result of clear records, regular checks and numbers you can rely on while you run the business.
