Australia's GST is a flat 10% goods and services tax added to most sales. The two calculations you actually need are adding it to a price and backing it out of a GST-inclusive total.
Run any figure through the free Australia GST calculator, or switch country with the general GST calculator.
Adding and removing 10% GST
Adding GST is simple: multiply the price by 1.1. A $200 service becomes $220, and the $20 difference is the GST. Removing it is where people slip up, because you cannot just take 10% off a GST-inclusive total.
add GST: total = price x 1.1
GST amount: total / 11
remove GST: price = total / 1.1The handy shortcut: the GST inside any inclusive price is simply that price divided by 11. So a $220 total contains $20 of GST and a $200 pre-tax price.
What is GST-free?
Not everything carries GST. Most basic foods, many health and medical services, some education courses, and certain childcare are GST-free, so no 10% applies. Most other goods and services, from electronics to restaurant meals to professional fees, are taxable. If you are unsure, the safe assumption for everyday retail and services is that the 10% applies.
Who registers for GST
A business must register for GST once its annual turnover reaches the registration threshold (and from the first dollar for ride-share and taxi work). Once registered, you add GST to your sales, report and pay it to the ATO through a Business Activity Statement (BAS), and claim back the GST you paid on business purchases as input tax credits. That credit system is why GST ultimately falls on the final consumer rather than on businesses along the way.
Quoting prices clearly
For consumers, advertised prices generally must be GST-inclusive, so the price on the shelf is what you pay. In business-to-business quotes, it is common to state amounts as "plus GST." Whenever there is any doubt, say whether a figure includes GST, because the gap is exactly 10% added or one-eleventh removed. The Australia GST calculator shows both the GST and the GST-exclusive price in one step.