Australia GST calculator
Australia GST calculatorAustralian GST is 10%, fixed by section 9-70 of the GST Act 1999. Because the rate is a tenth, the GST inside a GST-inclusive price is exactly one eleventh of it.
Worked example · Vat Amount
With Amount of 100, this model computes Vat Amount of 10. See the full working.
✓ Verified against 4 self-test cases Updated for 2026 · sources checked 2026-10-05
How gst in Australia is calculated
The rate on this page comes from the **statute itself**, not from a summary of it. Section 9-70 of the *A New Tax System (Goods and Services Tax) Act 1999* reads: *"The amount of GST on a taxable supply is 10% of the value of the taxable supply."* The figure is quoted from the compilation in force on 1 January 2026.
One tenth going on means **one eleventh coming off**, and that is the single most useful fact about Australian GST. A $110 tax-inclusive price contains $10 of GST: divide by 11, not by 10. Dividing by 10 is the common error and overstates the GST by a tenth.
This page covers the **rate only**, and the omission is deliberate. Australia does have a registration turnover threshold — section 23-15 of the Act creates one — but the Act leaves the *amount* to be prescribed by regulation, so the $75,000 figure that is widely quoted is not established by the Act, and the ATO’s own website refuses automated requests. Rather than publish a figure on trust, this page states the rate it can source and says plainly what it cannot. GST-free supplies — most basic food, health and education — carry no GST at all, which is a different mechanism from a reduced rate and so is not offered here as a band you can select.
Worked example
ShowHide the full working: 3 inputs, 5 computed steps
| Inputs | |
|---|---|
| Amount | 100 |
| Direction | Add VAT (net → gross) |
| B2B reverse charge applies | no |
| Computed by the engine | |
| Rate | 0.1 |
| Effective Rate | 0.1 |
| Net Amount ✓ pinned | 100 |
| Vat Amount ✓ pinned | 10 |
| Gross Amount ✓ pinned | 110 |
Every computed row comes from the engine, run on the inputs above. Rows marked ✓ pinned are also fixed by a published self-test, so a change to the model that moved them would fail its own tests.
Frequently asked questions
What is the GST rate in Australia?
10%, fixed by section 9-70 of the A New Tax System (Goods and Services Tax) Act 1999. There is only one rate; GST-free supplies such as most basic food carry no GST rather than a reduced one.
How much GST is on $100?
$10.00, for $110.00 including GST. On a $2,200 tax-inclusive invoice the GST is $200.00.
How do I work out the GST in a tax-inclusive price?
Divide by 11. Because GST is a tenth added on, it is an eleventh coming off — $110 contains $10 of GST. Dividing by 10 instead is the usual mistake and overstates the GST.
Why does this page not show the $75,000 registration threshold?
Because it could not be sourced. Section 23-15 of the GST Act creates a registration turnover threshold but leaves the amount to regulations, so the Act does not state $75,000, and the ATO website refuses automated requests. Publishing the figure would mean trusting secondary guidance for a claim with real consequences.
Sources
- Federal Register of Legislation - GST Act 1999 s 9-70 (10%) · checked 2026-10-05
Estimate. Not tax advice. The verification badge means the model reproduces the stated formula through 4 self-test cases; the sources support that the formula matches the rules.
Check the arithmetic yourself: how this calculator is verified — the formula behind every derived value, the 4 test cases the engine reproduces, and what the badge does and does not claim. Also available as machine-readable JSON.
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