Goods and services tax
GST calculator
Australian GST is 10%. To find the GST inside a price that already includes it, divide by 11 — not by 1.1. On a $1,100.00 price the GST is $100.00 and the amount before GST is $1,000.00.
GST component
$100.00
inside a $1,100.00 price
| Price excluding GST | $1,000.00 |
|---|---|
| GST (10%) | $100.00 |
| Price including GST | $1,100.00 |
Why you divide by 11, not 1.1
This trips people up constantly. If a price excludes GST you multiply by 1.1 to add it. But to pull the GST back out of a price that includes it, the GST is one eleventh of the total, not one tenth.
On $1,100.00: the pre-GST amount is $1,000.00 and the GST is $100.00. The GST is 10% of $1,000.00, but only 9.09% of the $1,100.00 you actually paid — which is $1,100.00 ÷ 11.
GST at common amounts
| Price inc. GST | GST | Ex GST | If price excluded GST |
|---|---|---|---|
| $50 | $4.55 | $45.45 | $55.00 |
| $100 | $9.09 | $90.91 | $110.00 |
| $500 | $45.45 | $454.55 | $550.00 |
| $1,100 | $100.00 | $1,000.00 | $1,210.00 |
| $5,000 | $454.55 | $4,545.45 | $5,500.00 |
| $25,000 | $2,272.73 | $22,727.27 | $27,500.00 |
When you have to register
You must register for GST once your business turnover reaches $75,000 a year ($150,000 for non-profits). Ride-share and taxi drivers must register from the first dollar, regardless of turnover. Once registered you charge GST on your sales and claim back the GST on your purchases.
What is not subject to GST
- Most basic food — bread, milk, plain meat, fruit and vegetables.
- Most medical and health services, and many medicines.
- Most education courses and childcare.
- Exports, and some precious metals and farmland.
The distinction between GST-free and input-taxed matters if you are registered: you can claim credits on GST-free supplies but not on input-taxed ones such as residential rent and most financial services.
Estimate only, not tax advice. Rate and threshold sourced from the ATO — see methodology.