Australian GST Calculator
Enter any amount. Get the GST-inclusive and GST-exclusive price instantly. Perfect for invoices, quotes, and pricing decisions.
Enter an amount to calculate GST
How GST is calculated in Australia
Australia's GST rate is 10%. The calculation depends on whether your starting price includes GST or not:
- GST-exclusive price: GST = price × 10%
- GST-inclusive price: GST = price ÷ 11
The "divide by 11" formula works because GST-inclusive prices contain the original amount plus 10%. Mathematically: price ÷ 1.1 gives the GST-exclusive amount, and price ÷ 11 gives the GST component.
GST inclusive vs exclusive prices
GST-inclusive prices show the total amount a customer pays, with GST already added. Australian Consumer Law requires most retail prices displayed to consumers to be GST-inclusive.
GST-exclusive prices show the base amount before GST. Business-to-business invoices and quotes often display prices this way, with GST shown as a separate line item.
When do you need to charge GST?
You must register for GST and charge it on taxable sales if your business has a GST turnover of $75,000 or more per year ($150,000 for non-profit organisations). Below this threshold, registration is optional.
If you are close to that line, use the dedicated $75,000 GST registration threshold guide to decide whether you are in optional, watch-list, or must-register territory.
Once registered, you charge 10% GST on most goods and services you sell, and you can claim GST credits on your business purchases.
FAQ
Is GST always 10% in Australia?
Yes. The GST rate in Australia has been 10% since its introduction on 1 July 2000. Some items are GST-free (such as basic food, health services, and education), but when GST applies, it is always 10%.
How do I calculate GST on an invoice?
If your invoice shows GST-exclusive prices, multiply each line item by 0.1 to get the GST amount, then add it to the subtotal. If you have a GST-inclusive total, divide by 11 to find the GST component.
What is a GST-inclusive price?
A GST-inclusive price is the total amount including the 10% GST. For example, if an item costs $100 plus GST, the GST-inclusive price is $110.
Do I need to charge GST if I'm not registered?
No. Only GST-registered businesses can charge GST. If you're not registered, you cannot add GST to your prices or claim GST credits on purchases.
How do I calculate the GST-exclusive amount from a total?
Divide the GST-inclusive amount by 1.1. For example, $110 ÷ 1.1 = $100 (the GST-exclusive amount).
Tax Accuracy & Sources
This calculator is an estimate tool and may not cover all personal circumstances. For state-based taxes, confirm details with your state or territory revenue office.
Turn the GST number into a reserve rule before the cash gets spent
This calculator answers the GST amount. Tax Buffer is the next step if you want to separate GST, income tax, and optional super from each payment instead of trying to clean it up at BAS time.
Turn the GST result into branded client paperwork
If you are pricing work for a client, move from the GST calculation into the branding-ready document set so invoices, quotes, credit notes, and follow-up paperwork all carry the right tax treatment and your business identity.
Uses 2025-26 ATO rates.