GST Calculator Australia

1. Sole trader pricing a consulting quote

Inputs: $1,500 ex-GST consulting fee

Output: GST $150.00, total invoice $1,650.00

The $1,650 is the figure that appears on the customer’s tax invoice. The $150 GST collected goes to BAS label 1A on the next quarterly statement. The trader keeps $1,500 and remits the $150 to the ATO when lodging.

2. Buyer extracting GST from a $4,400 supplier invoice

Inputs: $4,400 GST-inclusive purchase

Output: GST $400.00, ex-GST $4,000.00

The $400 is the GST credit the GST-registered buyer can claim at BAS label 1B, assuming the supplier’s tax invoice is valid (shows ABN, supplier name, tax invoice statement, GST amount and date). Without a valid tax invoice, the credit cannot be claimed.

3. Multi-line tax invoice with three line items (Total Invoice Rule)

Inputs: Item A $99.99, Item B $49.95, Item C $19.49 (all ex-GST)

Output: Per-line GST $9.999 / $4.995 / $1.949 (unrounded), summed = $16.943, rounded total GST $16.94, invoice total $186.37

This is the ATO Total Invoice Rule in action: keep per-line GST unrounded, then round the sum to the nearest cent at the end. Switching to the Taxable Supply Rule (round each line to $10.00 / $5.00 / $1.95) produces $16.95 — a one-cent drift that compounds across long invoices.

4. Cafe checking the $75,000 registration threshold

Inputs: Annual GST-inclusive sales $82,500

Output: ex-GST turnover $75,000.00, GST already embedded in prices $7,500.00

The cafe has just crossed the ATO mandatory GST-registration threshold of $75,000 ex-GST turnover (Source: business.gov.au) and must register within 21 days. Once registered, the $7,500 already collected from customers becomes GST payable on the first BAS.

5. Real-estate agent applying the margin scheme

Inputs: Sale price $660,000, original purchase price $440,000

Output: Margin $220,000, GST under margin scheme $20,000 (= margin / 11), net to vendor $640,000

Under the margin scheme the GST is calculated only on the $220,000 margin, not on the full $660,000 sale price — saving $40,000 of GST versus a standard sale. ATO eligibility is strict: the property must not have been acquired through a fully taxable supply, and both parties must agree in writing before settlement.

Australia's Goods and Services Tax (GST) is a flat 10% broad-based consumption tax. The rate has not changed since the GST began on 1 July 2000 under the A New Tax System (Goods and Services Tax) Act 1999, and the ATO continues to publish 10% as the standard rate.

Multiply the GST-exclusive amount by 1.1 to get the GST-inclusive total, or by 0.1 to isolate the GST. Worked example: $200 ex-GST x 1.1 = $220 inc-GST, with $20 of GST. The 10% rate applies whether the supply is goods, services, digital products, or imports of low-value goods.

Divide the inclusive total by 11 to get the GST component, and divide by 1.1 to recover the ex-GST amount. Worked example: $440 / 11 = $40 GST, and $440 / 1.1 = $400 ex-GST. The "divide by 11" shortcut is the form the ATO uses on its own tax-invoice guidance.

GST is 10% of the ex-GST price, which means it is 10/110 of the GST-inclusive price. The fraction 10/110 simplifies to 1/11, so GST included in any inclusive total = total / 11. This is the ATO-canonical formula and avoids the rounding drift that comes from chaining percentage operations.

A business must register for GST once its annual turnover (calculated on a GST-exclusive basis) reaches $75,000. The threshold is $150,000 for non-profit organisations and $0 for taxi, ride-source and limousine drivers — they must register from their first dollar. Business.gov.au and the ATO confirm a 21-day window to register once a threshold is reached.

Yes. ATO-listed GST-free supplies include most basic food, certain health and education services, exports of goods (subject to the 60-day rule), some childcare, and water and sewerage. Input-taxed supplies — such as residential rent and most financial services — are different again: the supplier does not charge GST but cannot claim GST credits on related purchases. Mark such items as "GST-free" in the multi-line invoice tab to keep them out of the GST total.

The ATO offers two rules. The Total Invoice Rule keeps each line’s GST unrounded internally and rounds only the summed total GST to the nearest cent (this calculator’s default). The Taxable Supply Rule rounds GST per line and then sums the rounded values. Rule choice is up to the supplier, but a tax invoice must apply only one rule consistently. The Total Invoice Rule produces less rounding drift on long invoices.

The calculator surfaces the figures you would put at label 1A (GST on sales) when you charge GST to a customer, and at label 1B (GST on purchases) when you extract GST from a supplier invoice. It does not lodge the BAS for you, and it does not handle GST adjustments, fuel tax credits, PAYG withholding or wine equalisation tax. For lodgement, use ATO online services for business or BAS-agent software.

Exports of goods are typically GST-free if exported within 60 days of the earlier of payment or invoice (the "60-day export rule"). Services are GST-free if effectively used or enjoyed outside Australia and the recipient is not in Australia when the service is performed. Marketplace operators selling low-value imported goods (under A$1,000) into Australia must collect GST under the simplified GST regime.

Goods valued at A$1,000 or less follow the low-value imported goods (LVIG) regime — GST is collected by the overseas marketplace at the point of sale. Goods over A$1,000 are taxed by the Australian Border Force at the border before release: GST is calculated on the customs value plus duty plus international transport and insurance. This calculator covers GST on domestic supplies; refer to ABF guidance for imports.