GST Calculator (Australia)
Add or remove 10% GST, estimate your BAS, and check whether you need to register. Built for small businesses and sole traders.
Add or remove GST
Quick rule: GST is 1/11th of a GST-inclusive price, or 10% of a GST-exclusive price. Results are rounded to the nearest cent.
BAS estimate (GST only)
Enter your totals for the BAS period. Figures below are GST-inclusive where GST applies. Use a negative amount for credit notes or refunds.
| BAS label | Amount |
|---|---|
| G1 – Total sales (incl. GST-free) | $0.00 |
| 1A – GST on sales | $0.00 |
| 1B – GST credits on purchases | $0.00 |
| Net GST payable to the ATO | $0.00 |
GST registration check
The GST turnover threshold is $75,000 for businesses and $150,000 for non-profits. You must register within 21 days of your turnover meeting or being projected to meet the threshold. Taxi and ridesharing drivers must register from their first fare regardless of turnover.
What counts as GST turnover? Your sales excluding GST. It includes GST-free sales (such as exports) but excludes input-taxed sales (such as residential rent and most financial supplies), and some other sales — check the ATO’s definition.
How GST works for sole traders
GST is a 10% tax on most goods and services sold in Australia. If you’re registered, you add GST to your prices, collect it from customers, and pay it to the ATO through your BAS – less any GST you paid on business purchases (your GST credits). If your GST credits are higher than the GST you collected, the ATO refunds the difference.
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Frequently asked questions
How do I calculate GST from a GST-inclusive price?
Divide the total by 11. For $110 including GST, the GST is $10 and the price before GST is $100.
How do I add GST to a price?
Multiply the ex-GST price by 1.1. For $100 ex-GST, the total is $110 and the GST is $10.
What is GST-free vs input-taxed?
GST-free sales (such as basic food, some health and education services and exports) have a 0% rate, and you can still claim credits on related purchases. Input-taxed sales (such as residential rent and most financial supplies) carry no GST, and you generally can’t claim credits on related purchases.
Do I have to register for GST as a sole trader?
Only if your GST turnover is $75,000 or more (or is projected to be), or you drive a taxi or rideshare. Otherwise registration is optional, but check with a registered tax agent whether it suits you.
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General information only, not tax or financial advice. Figures are estimates based on the standard 10% GST rate and ATO thresholds at the time of writing (September 2026). Check ato.gov.au or speak to a registered tax or BAS agent before lodging. See our disclaimer & privacy page.