BAS Preparation Checklist for Australian Businesses

What is a BAS?

A Business Activity Statement is the form Australian businesses use to report and pay certain tax obligations to the ATO. Depending on the business, it can cover GST, PAYG withholding, PAYG instalments and other amounts.

Not every business lodges a BAS, and those that do are not all reporting the same things or on the same cycle. What you report and how often depends on your registrations and circumstances — for example, whether you are registered for GST or withhold from employee wages. The ATO notifies businesses of their reporting obligations and cycle; confirm yours rather than assuming.

Why accurate bookkeeping matters before BAS preparation

A BAS is a summary of the underlying records. If transactions are unreconciled, miscoded or missing, the statement inherits those problems.

Businesses that keep bookkeeping current through the period usually find BAS preparation is a review exercise. Businesses that leave it until the statement is due find it is a reconstruction exercise, which takes longer and is more error-prone.

A useful sequence is to work through your normal month-end routine first, then start the BAS-specific review. If the month-end work is not done, do that first.

Sales and income records

Start by confirming the period's income is complete and correctly represented, with no duplicated or missing sales.

• All invoices for the period raised and entered
• Point-of-sale, e-commerce and platform settlements reconciled to recorded sales
• Customer payments allocated correctly, including part payments and deposits
• Credit notes and refunds recorded in the correct period
• Income that is not a normal sale identified and reviewed separately

Business expense records

Expenses need to be complete, coded consistently and supported by documentation. Purchases paid personally by an owner, or on a card not linked to the accounting file, are the ones most often missed.

• Supplier bills for the period entered and coded
• Card and cash purchases captured, including owner-paid business expenses
• Asset purchases distinguished from operating expenses
• Private-use portions identified where relevant
• Supporting documents attached or filed

GST records

If the business is registered for GST, review the GST treatment applied to transactions rather than relying on defaults. Software will apply whatever the account or supplier template says, which is not always right.

Pay particular attention to items where treatment commonly varies: insurance, government fees and charges, bank fees and interest, wages, residential rent, international purchases, and any sales that may not be taxable.

GST treatment depends on the nature of the supply and your registration. Where a transaction is unclear, flag it for your accountant or registered BAS agent instead of guessing.

Bank reconciliations

Every bank account used by the business should be reconciled to the closing statement balance for the period. Unreconciled transactions are, in effect, unverified figures on your statement.

Credit-card reconciliations

Business credit cards and payment platforms need the same reconciliation treatment as bank accounts. Card statements should agree with the accounting file, with each purchase coded and documented.

Payroll and PAYG withholding records

Where a BAS includes PAYG withholding, the amounts reported must agree with your payroll records for the period.

• All pay runs for the period processed and finalised
• Payroll reported through Single Touch Payroll as required
• Gross wages and PAYG withholding in the ledger agree with payroll reports
• Payroll journals posted to the correct accounts
• Any manual adjustments documented and explained

Checking transactions for correct GST treatment

Run a report of transactions by GST code and scan for outliers. A supplier normally coded one way that suddenly appears differently is worth checking, as is any large transaction.

Where a purchase over the relevant threshold has no valid tax invoice, the entitlement to claim may be affected. Make the missing document a task rather than an assumption.

Reviewing outstanding transactions

Before preparing the statement, clear anything sitting in suspense, holding or 'ask my accountant' accounts. Every item there is an unanswered question that will otherwise be resolved by guesswork.

Also review transactions dated outside the period but entered during it, and any journals posted since the last statement.

Supporting documents

Keep the documentation that supports the figures: tax invoices, receipts, bank and card statements, payroll reports and any explanations for unusual items. Attaching documents in your accounting software as you go is the lowest-effort way to do this.

BAS preparation checklist

1. Confirm the reporting period and what the statement is required to cover
2. Complete month-end bookkeeping for every month in the period
3. Reconcile all bank accounts to closing statement balances
4. Reconcile credit cards and payment platforms
5. Confirm all sales and income for the period are recorded once and correctly
6. Confirm all expenses are entered, coded and documented
7. Review GST treatment across income and expense transactions
8. Reconcile payroll, PAYG withholding and Single Touch Payroll reporting
9. Clear suspense, holding and unresolved items
10. Review the draft figures against the prior period and investigate unexpected movements
11. Assemble supporting documentation
12. Have the statement reviewed and lodged by the appropriate person or registered agent

Common record-keeping problems that delay BAS preparation

• Bank accounts unreconciled for part or all of the period
• Business purchases paid from a personal account and never captured
• Missing tax invoices for larger purchases
• GST applied by default to transactions where it does not belong
• Duplicated sales from a platform feed and a manual invoice
• Payroll processed but journals not posted or reconciled
• A growing balance in a suspense or holding account
• Prior-period adjustments made without documentation

When professional BAS support may help

BAS services provided for a fee are restricted under Australian law to registered BAS agents and registered tax agents. If you want someone else to prepare or lodge your statement for you, they need to be appropriately registered.

Support is commonly worth considering when the business has employees, multiple entities, mixed GST treatment across its sales, or a record of statements being prepared under time pressure.

Related services

Keep reading

• What Records Does a Business Need for BAS?

  The documents and records that sit behind an activity statement — sales, purchases, GST information, bank and card statements, payroll records and the supporting paperwork that explains them.

• Monthly Bookkeeping Checklist for Australian Small Businesses

  A month-end routine that keeps your records reliable: reconciliations, income and expense coding, debtors and creditors, payroll and super records, GST records and the reports worth reading.