GST and BAS
Practical steps, records and official guidance on GST and BAS.
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Questions
31. How do I add GST to a price or extract GST from an inclusive amount?
GST is 10% of the GST-exclusive price. To find the GST included in a GST-inclusive price, divide it by 11: $110 includes $10 of GST. The calculation applies to a wholly taxable sale; classify GST-free, input-taxed and mixed sales first.
- Choose whether your amount already includes GST, then calculate the components.
- Keep the source invoice and confirm that the whole amount is subject to GST.
The calculator does not classify GST-free, input-taxed or mixed supplies.
ATO GST guidance · How GST works · Calculating sales using the calculation worksheet · GST calculator
The bold answer was checked on 27 September 2026.
Link to question 3132. When must my business register for GST?
Register within 21 days once your GST turnover reaches $75,000 ($150,000 for a non-profit). Taxi and ride-sourcing drivers must register whatever their turnover. Check current and projected GST turnover and any compulsory-registration rule for your activity.
- Build a monthly turnover schedule and review what counts towards GST turnover.
- Use the ATO registration guidance to determine the trigger and registration date.
Taxi and ride-sourcing rules and other exceptions mean a general turnover threshold is not enough.
ATO GST guidance · Registering for GST
The bold answer was checked on 27 September 2026.
Link to question 3233. What is the difference between GST-free and input-taxed sales?
Neither includes GST in the price. You can claim GST credits for purchases you use to make GST-free sales, but not for purchases that relate to input-taxed sales, such as financial supplies and selling or renting out residential premises. Classify each sale before coding it, because the category decides whether GST credits on related purchases can be claimed.
- Classify each income stream using the ATO guidance and retain the basis for the classification.
- Review purchase credits and any apportionment separately for input-taxed activities.
Do not give both categories the same purchase-credit treatment just because no GST appears on the sale.
ATO GST guidance · GST-free sales · Input-taxed sales
The bold answer was checked on 27 September 2026.
Link to question 3334. Do I charge GST when selling to overseas customers?
Exported goods are GST-free if they are exported within 60 days of the earlier of receiving any payment or issuing an invoice for them. Some other supplies for consumption outside Australia, such as certain services, can also be GST-free. An overseas customer does not automatically make a sale GST-free.
- Record what you sold, where it is supplied or used, customer circumstances and any export evidence.
- Check the relevant goods or services rule before choosing the GST code.
Export conditions and evidence requirements differ between goods and services.
ATO GST guidance · GST-free sales
The bold answer was checked on 27 September 2026.
Link to question 3435. What information must appear on a valid tax invoice?
If a customer asks, you must issue a tax invoice within 28 days for any sale over $82.50 including GST. It must show that it is a tax invoice, your identity and ABN, the date, what was sold with quantity and price, the GST amount and how much of each sale is taxable. Sales of $1,000 or more must also show the buyer’s identity or ABN. Use an invoice checklist matched to the sale and the ATO’s tax invoice requirements.
- Check supplier identity and ABN, date, description, price and how the GST amount is shown.
- Check any buyer-identification requirement and clearly separate taxable and non-taxable items.
Requirements depend on the amount and nature of the sale; a heading alone does not make an invoice valid.
ATO GST guidance · Tax invoices
The bold answer was checked on 27 September 2026.
Link to question 3536. How do I prepare a BAS from my accounting records?
If your GST turnover is under $10 million, you generally report GST using Simpler BAS: total sales at G1, GST on sales at 1A and GST on purchases at 1B. Reconcile source records to each BAS label before approval.
- Check reporting period and GST basis, reconcile tax-coded transactions and investigate exceptions.
- Reconcile PAYG and other labels, retain the workpaper and obtain approval before lodgement.
Fictional worked example
For a fictional quarter, reconciled GST on sales at label 1A is $3,000 and eligible GST credits at label 1B are $1,800. The GST component payable is $1,200. Keep the sales and purchase reconciliations with the BAS workpaper, then reconcile other applicable BAS obligations separately. This example assumes the supplied GST amounts are already classified correctly.
The linked readiness gate checks a prepared pack. It does not prepare the BAS, decide tax treatment or authorise lodgement.
ATO business activity statements · GST reporting methods · Simpler BAS GST bookkeeping guide · BAS pack readiness checks
The bold answer was checked on 27 September 2026.
Link to question 3637. When is my BAS due, and when must I pay it?
Quarterly BAS is due on 28 October, 28 February, 28 April and 28 July. Monthly BAS is due on the 21st day of the following month. Payment is due by the same date. Use the period and due date shown for your BAS account.
- Record both lodgement and payment deadlines and any approved concession.
- Put the cash payment in the forecast and assign someone to retain the receipt.
General quarterly dates can differ from the dates that apply to your account.
ATO GST guidance · Due dates for lodging and paying your BAS · 13-week cash forecast
The bold answer was checked on 27 September 2026.
Link to question 3738. Should I account for GST on a cash or accrual basis?
A business with aggregated turnover under $10 million can choose either the cash or the accrual basis for GST. Compare the timing of receipts and payments under the methods your business is allowed to use.
- Check eligibility and the method currently recorded with the ATO.
- Model the effect on unpaid invoices and bills before changing method, and document transition adjustments.
Changing a report setting in Xero does not by itself change the ATO accounting method.
ATO GST guidance · Choosing an accounting method for GST
The bold answer was checked on 27 September 2026.
Link to question 3839. Why does my BAS GST figure differ from the GST balance in Xero?
On the cash basis, you account for GST on the BAS covering the period in which you receive or make payment for your sales and purchases. Bridge the BAS calculation to the GST control account at the same date and on the same basis.
- Separate opening balances, payments to the ATO, cash-basis timing and journals.
- List each reconciling item and clear unexplained differences before signing off.
A control account balance is not automatically the GST payable for one BAS period. The linked gate tests supplied tie-outs; it does not investigate reconciling items.
ATO GST guidance · Choosing an accounting method for GST · BAS pack readiness checks
The bold answer was checked on 27 September 2026.
Link to question 3940. How do I correct a mistake in a BAS I have already lodged?
You can generally correct a GST error on a later BAS lodged within the period of review for the period of the error, but not to claim GST credits after the 4-year time limit, and not more than once. Revising the earlier BAS instead can attract penalties or general interest charge. Work out whether the error can be corrected on a later BAS or requires a revision.
- Record the original period, error type, amount, discovery date and supporting transactions.
- Apply the ATO’s correction conditions and retain the approved amendment or later-period adjustment.
Do not choose a later-period correction without checking the period of review and the 4-year credit time limit.
ATO GST guidance · How to correct GST errors · GST errors that can’t be corrected on a later BAS
The bold answer was checked on 27 September 2026.
Link to question 40Reviewed 11 September 2026. Use the BAS period, GST accounting basis and account due date being reviewed. Tax guidance must match your year and circumstances.
One of 10 topics in the 100 Australian accounting questions.