Requirements for lodging a Business Activity Statement (BAS) in Australia in 2026

A Business Activity Statement (BAS) is a tax reporting form issued by the Australian Taxation Office (ATO) to businesses registered for Goods and Services Tax (GST). It allows businesses to report and pay multiple tax obligations — including GST, Pay As You Go (PAYG) withholding, PAYG instalments, and fringe benefits tax (FBT) instalments — in a single submission. Lodging a BAS on time and with accurate figures is a legal obligation for every GST-registered business in Australia.

For most small businesses, the BAS is lodged quarterly. Monthly lodgement applies to businesses with a GST turnover above $20 million or to those who choose to report more frequently. Some eligible businesses may lodge annually. Getting the process right from the start avoids penalties and keeps your business compliant with the ATO.

What this procedure is and what it’s for

A BAS is the mechanism through which GST-registered businesses in Australia account for the tax they have collected on sales and the GST credits they can claim on business purchases. Beyond GST, the same form captures PAYG withholding amounts (tax deducted from employees’ wages), PAYG instalment amounts (prepayments toward your own income tax liability), FBT instalments, wine equalisation tax and fuel tax credits where relevant.

Who must lodge a BAS:

• Any business or sole trader with a GST turnover at or above $75,000 per year (or $150,000 for non-profit bodies) must be registered for GST and lodge a BAS.
• Businesses below those thresholds that have voluntarily registered for GST must also lodge.
• Employers with PAYG withholding obligations must report those amounts on a BAS regardless of GST turnover.
• Taxi and ride-sharing drivers must register for GST from the first dollar of fare income and lodge a BAS.

The official body responsible for BAS administration and compliance is the Australian Taxation Office (ATO), reachable at ato.gov.au or on 13 28 66.

Documents required

Gather the following records before starting your BAS. All documents must be in English or accompanied by a certified translation. No apostille or notarisation is required for any of these items.

Core business identity documents

• Australian Business Number (ABN) confirmation — your ABN is pre-filled on the BAS, but keep your ABR registration details on hand.
• GST registration confirmation from the ATO — confirms your effective registration date and reporting cycle.

Financial records for the reporting period

• Tax invoices for all business purchases (originals or scanned copies) — invoices above $82.50 including GST must show the supplier’s ABN, a description of the goods or services, the GST amount and the date. You must hold the invoice before claiming an input tax credit.
• Sales records — totals broken down into taxable sales, GST-free sales and input-taxed sales for the period.
• Bank statements — used to reconcile cash received and payments made.
• Cash register reports or point-of-sale summaries (if applicable).
• Payroll records (if you have employees) — total wages paid and total PAYG withholding amounts for the period.
• PAYG instalment rate or amount — shown on your pre-filled BAS if the ATO has set one for you.
• FBT instalment amount — shown on your pre-filled BAS if applicable.
• Fuel tax credit calculations (if your business uses fuel in eligible activities).
• Previous BAS lodgements — useful for cross-checking opening balances and carry-forward credits.

If using accounting software

• GST detail report exported from your accounting platform (e.g. Xero, MYOB, QuickBooks, Reckon) for the period.
• Payroll summary report for PAYG withholding figures.

Distinction between originals and copies: the ATO does not require you to submit physical documents with your BAS. However, you must hold valid originals (or complete electronic copies) of tax invoices and receipts and make them available if the ATO requests them during a review or audit.

Steps to complete the procedure

Before you start: confirm your BAS reporting cycle (monthly, quarterly or annual) by checking your ATO correspondence or logging into ATO Online Services.

1. Identify the reporting period covered by the BAS (e.g. 1 April – 30 June for the March quarter).
2. Reconcile your accounts — match your sales and purchase records to your bank statements to ensure the figures are accurate before entering anything.
3. Calculate your GST liability: total GST collected on taxable sales minus total GST credits on eligible purchases.
4. Calculate your PAYG withholding total — sum all tax withheld from employee wages during the period.
5. Note any PAYG instalment or FBT instalment amount shown on your pre-filled BAS.
6. Log in to ATO Online Services for Business at ato.gov.au/business — this is the main portal for BAS lodgement. No appointment is needed.
7. Alternatively, link your myGov account to the ATO and lodge through myGov if you are a sole trader.
8. If you use ATO-integrated accounting software, lodge directly from within the platform — Xero, MYOB and QuickBooks all support direct lodgement via the ATO’s SBR2 channel.
9. If you use a registered BAS agent or tax agent, provide them with your reconciled records; they lodge on your behalf and generally receive an extended deadline.
10. Review every field on screen before submitting. Confirm the figures match your records.
11. Submit the BAS and arrange payment of any net amount owing by the due date (see Fees and timelines below). Payment can be made by BPAY, credit card, direct debit or at Australia Post.

Paper lodgement: a paper BAS form can be requested by calling the ATO on 13 28 66 if you cannot lodge online.

Estimated time to complete: 1–3 hours for businesses with well-maintained records; longer if accounts require reconciling first.

Fees and timelines

• Lodgement fee: nil — the ATO does not charge a fee to lodge a BAS.
• Registered agent fee: if you use a BAS agent or tax agent, their professional fee applies; this varies by provider.
• Late lodgement penalty (failure-to-lodge): one penalty unit per 28-day period (or part thereof) the BAS is overdue, up to a maximum of five penalty units. The penalty unit rate for 2025–26 is approximately $330, giving a maximum penalty of around $1,650 for most small businesses. Higher maximum penalties apply to medium and large businesses.
• General interest charge (GIC): interest accrues daily on any unpaid tax debt from the due date.
• Quarterly BAS due dates: 28 days after the end of each quarter — 28 October, 28 February, 28 April and 28 July. Note: businesses lodging through a registered tax or BAS agent may receive an extended deadline; confirm this with your agent.
• Monthly BAS due date: the 21st day of the following month.
• Annual BAS due date: generally 31 October following the end of the financial year for eligible small businesses.
• Processing time: online submissions are processed in real time. ATO refunds (where credits exceed obligations) generally arrive within 14 business days of lodgement.
• Validity of a lodged BAS: a lodged BAS is a permanent record for that specific period; it does not expire, but it can be amended if errors are found.

Common mistakes and how to avoid them

• Missing the lodgement deadline — the due date is 28 days after the end of the quarter, not the end of the following month. Set a calendar reminder at least a week before the due date to allow time for reconciliation.
• Claiming GST credits without a valid tax invoice — you cannot claim an input tax credit for a purchase over $82.50 (inc. GST) unless you hold a tax invoice that shows the supplier’s ABN, the GST amount and a description of the goods or services. Collect and file invoices at the point of purchase.
• Incorrectly categorising sales — not all sales are taxable at 10%. GST-free sales (e.g. most fresh food, some health services, exports) and input-taxed sales (e.g. residential rent, financial supplies) must be reported in separate fields (G2 and G3 respectively), not included in taxable sales. Miscategorisation leads to an overstated GST liability or an incorrect refund.
• Omitting PAYG withholding amounts — if you withhold tax from employee wages, this must be reported on the BAS in the W1 and W2 fields even if the amounts have already been paid to the ATO. Leaving these blank triggers discrepancies in ATO records.
• Lodging without reconciling to bank statements — submitting figures taken directly from accounting software without checking them against actual bank transactions is a common source of errors that can trigger an ATO review or require a costly amendment later.

Frequently asked questions

Do I need to lodge a BAS if my business had no income during the period? Yes. If you are registered for GST you must lodge a BAS for every reporting period, even if there is nothing to report and no tax is owing. This is called a nil BAS. You can lodge a nil BAS in under a minute through ATO Online Services or by calling the ATO on 13 28 66.

Can I lodge my BAS through a registered agent? Yes. A registered BAS agent or tax agent can prepare and lodge on your behalf. Registered agents often receive extended lodgement deadlines from the ATO. Verify that any agent you use is registered with the Tax Practitioners Board (TPB) at tpb.gov.au before engaging them.

What happens if I discover an error on a BAS I have already lodged? You can revise a previously lodged BAS through ATO Online Services for Business or through your registered agent. If the revision results in an underpayment of tax, the general interest charge (GIC) will apply to the shortfall from the original due date. Correct errors as soon as you identify them to minimise interest costs.

How long do I need to keep my BAS records? The ATO requires you to retain all records related to a BAS for five years from the date of lodgement. Records must be in English, legible and accessible for inspection if the ATO conducts a review or audit. Electronic records stored in accounting software meet this requirement.

I use cash accounting — does that change how I complete the BAS? Yes. Under the cash (receipts) basis, you report GST in the period you receive payment on sales and in the period you make payment on purchases, rather than when invoices are issued. Most businesses with a turnover below $10 million can elect to use cash accounting. Your pre-filled BAS will reflect the basis the ATO has on record for you. If you are unsure which basis you are using, check your ATO correspondence or speak to a registered BAS agent.

What to do next

The three most important items to have ready are your ABN, valid tax invoices for all business purchases, and reconciled sales and payroll records for the reporting period. Your first concrete step is to log in to ATO Online Services for Business or your ATO-integrated accounting software to access your pre-filled BAS for the current period.

BAS requirements, penalty unit amounts and lodgement deadlines are subject to change. Always verify the current rules directly with the Australian Taxation Office at ato.gov.au or by calling 13 28 66 before lodging, particularly if your business circumstances have changed since your last BAS.