How to Calculate GST in Australia: Add 10% to a Price
To add standard 10% GST to a GST-exclusive taxable price, multiply the price by 1.10. To find the GST in a fully taxable GST-inclusive total, divide that total by 11. Use the calculator below to see the GST amount and both price figures.
The two GST calculations
For a GST-exclusive amount, calculate GST = price × 0.10, then add it to the original amount. For example, $100 before GST produces $10 GST and a $110 total.
For a fully taxable GST-inclusive amount, calculate GST = total ÷ 11. A $110 total contains $10 GST and $100 before GST. The calculator handles either direction.
How to use the GST calculator
- Choose whether your starting amount is before GST or already includes GST.
- Enter the amount in Australian dollars.
- Read the total, pre-GST amount and GST component together.
For clean records, use the correct basis consistently when comparing revenue, costs or prices. The tool is a quick arithmetic check; it does not decide whether a particular sale is taxable.
When this simple estimate may not apply
Australia’s standard GST rate is 10%, but not every supply is treated the same way. Some supplies may be GST-free or input taxed, and special rules can apply. The calculator assumes a fully taxable supply using the standard rate. Check the ATO explanation of how GST works for your situation.
GST registration is a separate question from the arithmetic. The ATO explains when an enterprise needs to register in its GST registration guidance.
Try the related calculator
Use the Australian GST calculator to apply the formula to your own figures. Results are estimates using the assumptions shown on the tool page.
Frequently asked questions
How do I add 10% GST to a price?
Multiply a GST-exclusive taxable price by 0.10 to find GST, then add GST to the original price. Equivalently, multiply the original price by 1.10.
How do I remove GST from a GST-inclusive amount?
For a fully taxable amount at the standard rate, divide the total by 1.1 to get the pre-GST price; divide by 11 to get the GST component.
Does every Australian product or service have GST?
No. GST treatment depends on the supply and circumstances. The calculator is only a standard-rate estimate; use ATO guidance for classification and registration questions.