How GST is calculated
Australia's goods and services tax (GST) is 10% of the price before tax. There are two everyday calculations:
- Adding GST: multiply the GST-exclusive price by 1.1. $250 becomes $275.
- Finding GST in a GST-inclusive price: divide by 11. A $275 price includes $25 GST, so the price before GST is $250.
Common mistake: taking 10% off a GST-inclusive price. 10% of $275 is $27.50, which overstates the GST. The correct GST is $275 ÷ 11 = $25.
GST quick reference table
| Amount | GST to add | Price incl. GST | GST included if amount is GST-inclusive |
|---|---|---|---|
| $10.00 | $1.00 | $11.00 | $0.91 |
| $50.00 | $5.00 | $55.00 | $4.55 |
| $100.00 | $10.00 | $110.00 | $9.09 |
| $250.00 | $25.00 | $275.00 | $22.73 |
| $500.00 | $50.00 | $550.00 | $45.45 |
| $1,000.00 | $100.00 | $1,100.00 | $90.91 |
| $2,500.00 | $250.00 | $2,750.00 | $227.27 |
| $5,000.00 | $500.00 | $5,500.00 | $454.55 |
| $10,000.00 | $1,000.00 | $11,000.00 | $909.09 |
When you need to register for GST
You must register for GST when your business's GST turnover reaches $75,000 a year, or $150,000 for a non-profit organisation. If you provide taxi, limousine or ride-sourcing services, you must register regardless of turnover.
Once registered, you charge GST on taxable sales, claim credits for GST in your business purchases, and lodge business activity statements (BAS).
Common questions
How do I calculate GST in Australia?
GST is 10%. To add GST, multiply the price by 1.1, so $100 becomes $110. To find the GST in a price that already includes it, divide by 11, so a $110 price contains $10 GST.
Why divide by 11 and not take away 10%?
Because the 10% is charged on the price before GST, not the final price. Taking 10% off $110 gives $99, which is wrong. Dividing $110 by 11 gives the correct $10 GST, leaving $100.
When do I have to register for GST?
When your business's GST turnover reaches $75,000 a year, or $150,000 for non-profits. Taxi, limousine and ride-sourcing drivers, including Uber drivers, must register no matter how much they earn.
Can I register for GST below $75,000?
Yes. Registering voluntarily lets you claim GST credits on business purchases, but you'll then need to charge GST on your sales and lodge activity statements.
What items don't have GST?
Many items are GST-free, including most basic food, some medical and health services, most education courses, and exports. Residential rent and the sale of existing homes are input-taxed, so no GST is charged on them.
How do I show GST on an invoice?
If you're registered, issue a tax invoice that shows your ABN and either the GST amount or a statement that the total includes GST. Tax invoices for sales of $1,000 or more must also show the buyer's identity or ABN.
Sources
This calculator is for general information. It doesn't decide whether an item is taxable, GST-free or input-taxed. For that, check the ATO's guidance or ask a registered tax agent.