GST Calculator — Australia
This is an Australian GST calculator. Enter an amount and choose whether to add 10% GST or extract the GST component from a GST-inclusive figure. GST is imposed at a flat 10% under A New Tax System (Goods and Services Tax) Act 1999 (Cth). Use it for invoicing, BAS preparation, and matter costing — note that some supplies are GST-free or input-taxed.
What this calculator does
The Australian Goods and Services Tax (GST) is a broad-based 10% consumption tax on most goods, services, and other items sold or consumed in Australia. It is administered by the ATO under A New Tax System (Goods and Services Tax) Act 1999 (Cth). Businesses registered for GST charge GST on taxable supplies and claim input tax credits on business acquisitions. This calculator handles the two most common tasks: adding GST to a net amount and extracting the GST component from a gross amount.
Legal basis
GST is imposed under A New Tax System (Goods and Services Tax) Act 1999 (Cth). The rate of 10% is set in s 9-70. Registration requirements are in Division 23. GST-free supplies are listed in Division 38 (e.g. basic food, health, education). Input-taxed supplies are in Division 40 (e.g. financial supplies, residential rent).
How the calculation works
To add GST: GST = amount × 0.10; gross = amount + GST. To extract GST from a GST-inclusive amount: GST = gross ÷ 11; net = gross − GST. The rate is fixed at 10% under s 9-70 of A New Tax System (Goods and Services Tax) Act 1999 (Cth).
Interactive calculator coming soon
For a net amount of $1,000 with GST added: GST = $100, total = $1,100. For a GST-inclusive amount of $1,100: GST component = $100, net = $1,000.
In the meantime, use the worked example above to validate your figures and confirm the final amount with the relevant revenue office or authority before relying on it in a matter.
Start free trialWhat you fill in
- Amount (AUD) (currency): Must be a positive number
- Calculation type (select): Required
Limitations
- Assumes the supply is a taxable supply — does not identify GST-free or input-taxed supplies
- Does not handle mixed supplies (partly taxable, partly GST-free)
- Does not calculate GST on imported goods or the tourist refund scheme
- Does not address the margin scheme for property (Division 75)
- Does not calculate the wine equalisation tax or luxury car tax (separate taxes)
What to do next
If you are preparing a BAS or need to determine whether a supply is taxable, GST-free, or input-taxed, consult the ATO or your tax adviser. For legal practices, Quillio helps with matter costing and invoice review — see /practice-areas/commercial-lawyers.
Calculator FAQs
Is the GST rate always 10%?
Yes — the Australian GST rate has been 10% since its introduction on 1 July 2000 and is fixed under s 9-70 of the GST Act. There is no reduced rate.
What supplies are GST-free?
Division 38 of the GST Act lists GST-free supplies including basic food, most health services, education, exports, and some religious and charitable supplies. GST-free supplies carry no GST but the supplier can still claim input tax credits.
What are input-taxed supplies?
Division 40 covers input-taxed supplies, mainly financial supplies and residential rent. No GST is charged on these supplies, but the supplier cannot claim input tax credits on related acquisitions.
How does the margin scheme work?
Under Division 75, GST on certain property sales can be calculated on the margin (sale price minus original purchase price) instead of the full sale price. This calculator does not model the margin scheme — consult your tax adviser.
Do I need to register for GST?
Under Division 23, registration is required if your annual turnover is $75,000 or more ($150,000 for non-profit organisations). Below that threshold, registration is optional.
Is this tax advice?
No — this is a simple arithmetic calculator for the 10% GST rate. Whether a particular supply attracts GST depends on its classification. Consult the ATO or your adviser.
Does GST apply to legal fees?
Yes — legal services are generally taxable supplies. GST-registered law firms must charge 10% GST on their fees and can claim input tax credits on business acquisitions.
Get help with the matter
For commercial lawyers and in-house counsel, Quillio reviews contracts for GST treatment, identifies GST-inclusive vs GST-exclusive pricing clauses, and flags Division 75 margin scheme provisions in property contracts. See /practice-areas/commercial-lawyers.
This calculator performs simple GST arithmetic at the flat 10% rate. It does not determine whether a supply is taxable, GST-free, or input-taxed. Consult the ATO or your tax adviser for supply classification.
Quillio handles the next steps.
The calculator gives you the number. Quillio handles the rest of the matter — drafting, review, research, and correspondence. The free trial requires no sales call.
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