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Financial 📅 2026-07-12

BAS Preparation Checklist: A Step-by-Step Guide for Australian Business

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MegaCalcOnline Business Team
Australian small business & tax calculators · Updated 2026-07-12

Preparing a Business Activity Statement is really good record-keeping caught up at quarter's end. This step-by-step checklist walks through what to gather, how to total your GST on sales and purchases, working out whether you pay or receive a refund, and lodging on time.

What the BAS Is

The Business Activity Statement (BAS) is how GST-registered Australian businesses report and pay their GST to the ATO, usually quarterly. It reports the GST you collected on sales, the GST you paid on purchases, and the difference — which you either pay to the ATO or receive back. It can also cover PAYG withholding and instalments. Preparing it accurately and on time avoids penalties and interest.

Work out GST amounts with our GST calculator as you go.

Before You Start: Gather Everything

Good BAS preparation is really good record-keeping caught up at the end of the quarter. Before you fill anything in, gather:

If these are kept up to date through the quarter, BAS time is a review rather than a scramble. Our bookkeeping checklist covers keeping on top of this.

Step 1: Total Your GST on Sales

Add up the GST you collected on all taxable sales during the period. Remember that not everything is taxable — GST-free items like most basic food, and input-taxed sales, are treated differently, so separate them out. Getting the GST-on-sales figure right is the foundation of the whole statement.

Step 2: Total Your GST on Purchases

Add up the GST you paid on business purchases, since you can generally claim this back as a credit. Only claim GST on genuine business expenses for which you hold a valid tax invoice, and apportion anything used partly for private purposes.

No valid tax invoice, no GST credit. You generally cannot claim a GST credit on a purchase without a valid tax invoice showing the supplier's ABN and GST. Keeping every tax invoice through the quarter is what makes this step possible.

Step 3: Work Out the Net Position

Net GST = GST collected on sales − GST paid on purchases

If you collected more GST than you paid, you pay the difference to the ATO. If you paid more than you collected — common when you have made large purchases — you receive a refund. Include any PAYG withholding or instalments that also belong on the statement.

Step 4: Lodge and Pay on Time

Deadlines matter. Late lodgement and late payment can attract penalties and interest. Note your quarterly due dates, and if cash flow is tight, lodge on time even if you need to arrange a payment plan — lodging late is the more expensive mistake.

When to Get Help

Many small businesses prepare their own BAS, but a registered BAS agent or accountant is worth considering if your affairs are complex, if you are unsure about GST treatment of particular items, or if you simply want the reassurance. They can also often lodge later on your behalf. However you prepare it, keep every record for five years — the ATO can review past statements, and good records are your protection.

Frequently Asked Questions

What is a BAS?

The Business Activity Statement is how GST-registered Australian businesses report and pay GST to the ATO, usually quarterly. It reports GST collected on sales, GST paid on purchases, and the difference, and can also cover PAYG withholding and instalments.

What records do I need to prepare a BAS?

All sales invoices you issued, all purchase invoices and receipts, bank and credit card statements for the period, records of wages and tax withheld, and your previous BAS for reference. Kept up to date through the quarter, BAS time becomes a review rather than a scramble.

How do I calculate my net GST?

Subtract the GST you paid on business purchases from the GST you collected on sales. If you collected more, you pay the difference to the ATO; if you paid more, you receive a refund. Add any PAYG withholding or instalments that belong on the statement.

Can I claim a GST credit without a tax invoice?

Generally no. You need a valid tax invoice showing the supplier's ABN and GST to claim a GST credit on a purchase. Keeping every tax invoice through the quarter is what makes claiming credits possible.

What happens if I lodge my BAS late?

Late lodgement and payment can attract penalties and interest. Note your quarterly due dates and lodge on time even if cash flow is tight — you can arrange a payment plan, and lodging late is the more expensive mistake.

⚠️ General Information Only: This article provides general information about business, tax and GST administration in Australia. It is not tax, accounting, or legal advice. Rules, rates and thresholds change and depend on your circumstances. Always confirm current requirements with the ATO (ato.gov.au) or a registered tax or BAS agent before acting.