BAS record-keeping, the painless version.

If you're GST-registered, you lodge a Business Activity Statement (BAS) - usually quarterly, sometimes monthly. The work is mostly in keeping clean records throughout the period. This guide explains what records the ATO expects, for how long, and what makes BAS filings go from a weekend nightmare to a 30-minute task.

i.BAS in two paragraphs

The Business Activity Statement is the ATO form on which you report GST, PAYG withholding (if you have employees), and other obligations. For most small businesses it's lodged quarterly - by the 28th of the month following the quarter end (so April BAS due 28 July, etc.). Sole traders and small businesses with annual GST turnover below AUD $20 million typically use the quarterly cycle.

The BAS itself takes the underlying records and rolls them up into summary figures. The ATO doesn't usually ask to see your raw records when you lodge - but they can audit you up to five years later. The audit lottery is real for small businesses; clean records prevent it from becoming expensive.

ii.What you need to keep

The ATO requires records that explain every transaction. For most small businesses this means:

Income records

• Tax invoices for every sale (or a record of cash sales where invoices aren't issued)
• Receipts or statements showing payments received
• Bank statements showing deposits
• Records of asset sales (if you sold equipment or vehicles)

Expense records

• Tax invoices for every business expense over AUD $82.50 (including GST) - required to claim the GST credit
• Receipts or bank/card statements for smaller expenses
• Mileage records if you use your own vehicle for business
• Records of asset purchases (depreciation evidence)

Other records

• Bank statements (business accounts)
• Records of stock on hand if you sell goods
• Payroll records if you have employees
• Records of any GST adjustments (bad debts, returns, etc.)

iii.How long to keep records

The ATO's minimum: 5 years from the date you lodge the relevant return. For most BAS records, that's 5 years from when you lodged the BAS that the record supports.

Practical advice: keep them for 7 years. Some specific records have longer requirements:

• Capital assets - keep records as long as you own the asset, plus 5 years after disposal
• Employee records - 5 years after the employee leaves
• FBT records - 5 years from lodgement

iv.Paper or digital - what's acceptable?

Digital records are fully acceptable as long as:

• The information is true and clear (legible)
• It's in English (or easily translatable)
• It can be produced if the ATO requests
• It's backed up - if the records are digital-only and you lose the device, the ATO doesn't accept "I lost the laptop"

Most modern accountants and bookkeepers prefer digital. Receipt photos taken on a phone are acceptable as long as they're legible. PDFs of invoices generated by software qualify.

v.The BAS form, simplified

The main BAS boxes most small businesses fill in:

Sales (output GST)

• G1: Total sales (including GST). The sum of all your invoices over the period.
• G2: Export sales (GST-free exports). Subset of G1.
• G3: Other GST-free sales. Subset of G1.
• G4: Input-taxed sales (e.g. residential rent if applicable). Subset of G1.
• 1A: GST on sales (the GST you've collected).

Purchases (input tax credits)

• G10: Capital purchases (assets) including GST.
• G11: Non-capital purchases (general expenses) including GST.
• 1B: GST on purchases (the GST you can claim back).

The bottom line

Box 9: GST refund or amount owing = 1A - 1B. If you collected more than you paid, you owe the ATO. If you paid more than you collected (capital purchase quarter, or you're in an export business), the ATO refunds you.

vi.The 30-minute BAS workflow

If your records are clean throughout the quarter, the BAS itself is short. The workflow:

1. Export your invoice list for the quarter from VioBusiness (CSV). Sum the totals - that's G1. Identify GST-free portion - that's G2/G3.
2. Export your expense list. Filter to business expenses with tax invoices. Sum GST amount - that's part of 1B.
3. Add fuel tax credits if you claim them.
4. Calculate: GST collected (1A) - GST credits (1B) = amount payable or refundable.
5. Lodge via the ATO Business Portal or via your tax agent. Pay any amount owing.

For businesses with multiple income streams (taxable, GST-free, input-taxed), this gets more complex - usually best to have a bookkeeper or accountant handle it.

vii.Common BAS mistakes

• Claiming GST credits on private expenses. A laptop you use 70% for work and 30% personal can only have 70% of its GST claimed.
• Forgetting BAS instalments. If you're on PAYG instalments, your BAS includes the quarter's instalment too.
• Missing the lodgement date. Late lodgements attract a Failure to Lodge penalty. Quarterly BAS is due 28 days after quarter end (with a 2-week extension if lodged via a tax agent).
• Claiming credits without a tax invoice. For purchases over AUD $82.50 you need a valid tax invoice on file before claiming. Bank statement alone isn't enough.
• Forgetting to lodge a Nil BAS. Even if you had no activity, you must still lodge a BAS for the quarter showing zero amounts.

viii.How VioBusiness supports BAS preparation

VioBusiness produces records that map directly to BAS lines:

• Invoices CSV: Filtered by date range, gives you G1 (total sales) and 1A (GST collected) - and separately identifies GST-free invoices.
• Expenses CSV: With receipt photos attached on each entry, gives you G11 (non-capital purchases) and 1B (GST credits claimable).
• Local-first storage: Records are kept on your phone, satisfying the ATO's "must be capable of being produced" rule.
• Cloud Backup tier (optional): Encrypted off-device backup means a lost phone doesn't take your records with it.

Many Australian small businesses use VioBusiness for invoicing and expense capture during the quarter, then hand the CSVs to a bookkeeper or BAS agent who handles the actual lodgement.

Disclaimer: BAS rules are detailed for specific industries (margin scheme, simplified GST accounting, GST grouping). For complex cases consult a registered BAS agent, tax agent, or the ATO.

ix.Get VioBusiness

The clean, offline-first invoice and expense app for Australian small business. AUD $29.99 lifetime. More on the Australia page. Or see our ABN tax invoice guide for the invoice-specific rules.