Growth CircleGST percentage calculator
Find out what GST rate was charged on an invoice.
Your estimate
Estimates only, based on the rules shown here as of 28 September 2026 for tax year 2026-27 (assessment year 2027-28). Rules change, so please verify current requirements or ask a professional before acting.
How it works
The GST rate is the GST amount divided by the amount before GST, as a percentage. GST amount is the difference between the total and the amount before GST.
When to use it
Use it to check that a supplier charged the correct rate before you claim input tax credit. If the result is not a standard rate, ask the supplier or a professional to check the invoice.
Questions
What if the result is not a standard rate?
The invoice may have rounding, discounts or a mix of items. Check the invoice details.
Can I use it for inclusive prices?
Yes. Enter the price before GST and the price you actually paid.
Want this checked properly?
A calculator gives an estimate. We can review your actual documents and give you a computation you can rely on.