What is GST in Australia?
GST stands for goods and services tax. It is a 10% tax on most things sold or consumed in Australia: the flat white you grab on the way to work, a new washing machine, your accountant's invoice, a haircut. It began on 1 July 2000 and is collected by businesses on behalf of the Australian Taxation Office (ATO).
This page pairs a free GST Calculator Australia tool with a plain-English guide. If you have ever stared at an invoice wondering how to calculate GST from total amounts like a A$99 receipt, it was written for you.
Here is the basic idea. A business registered for GST adds it to its prices and collects it from customers. It then passes that money to the ATO. In return, the business can claim back the GST it paid on its own purchases, which are called GST credits. So the tax mostly lands on the final customer, not the business in the middle.
Current GST rate and what is GST-free
The rate is a single, flat 10%. It is the same in Sydney, Perth, Hobart and Alice Springs. There are no state versions and no reduced bands, which makes the maths easier than in many countries.
That said, not everything carries GST. Three buckets are worth knowing:
- Taxable (10%): most retail goods, restaurant meals, tradie work, software, consulting.
- GST-free (0%): basic food like bread and milk, many medical and education services, most exports.
- Input-taxed: residential rent and financial supplies such as loan interest. No GST is charged, but the seller usually cannot claim credits either.
Registration is compulsory once your GST turnover reaches A$75,000 (A$150,000 for non-profits). Taxi and rideshare drivers must register from the first dollar. Always confirm the current settings on the official ATO website.
How to calculate GST when you add it
Start with the price before GST. If you have ever wondered how is GST calculated on a quote, there are two routes, and both land on the same number.
Total = price + GST (or price × 1.1)
Say a plumber quotes A$600 plus GST. Ten percent of A$600 is A$60, so you pay A$660. That is really all there is to how to calculate GST on a quote. The slightly harder case is the one in the next section, when the GST is already buried in the price.
How to calculate GST backwards (removing it)
This is the question behind most searches: how do I calculate GST when all I have is the final amount? The trick is that GST is one-eleventh of a GST-inclusive price, not one-tenth.
Price before GST = total − GST (or total ÷ 1.1)
Knowing how to calculate GST from total receipts is the whole point of this rule. Why eleven? Because the total is 110% of the original price. The GST is 10 of those 110 parts, so 10/110, which simplifies to 1/11. Take a A$1,100 total. Divided by 11, the GST is A$100 and the price before GST is A$1,000.
Lots of people ask how do you calculate GST in this direction and then simply knock 10% off the total. On A$1,100 that gives A$990, which is wrong by A$10. It is the most common slip we see.
GST-inclusive vs GST-exclusive prices
A GST-inclusive price already contains the tax. A GST-exclusive price (often written "ex GST" or "+ GST") does not. Consumer prices in shops, cafés and online stores are normally inclusive. Trade quotes and invoices between businesses are often exclusive.
| Question | Exclusive price | Inclusive price |
|---|---|---|
| Does it include GST? | No | Yes |
| Typical place you see it | Trade quotes, B2B invoices | Shop shelves, menus, websites |
| To get the other one | × 1.1 | ÷ 1.1 |
| GST portion | price × 0.10 | total ÷ 11 |
Step-by-step worked examples
Example 1: an electrician's quote (adding GST)
An electrician quotes A$2,350 to rewire a granny flat, plus GST. Step one: A$2,350 × 0.10 = A$235. Step two: A$2,350 + A$235 = A$2,585. That is the figure that will appear on the final invoice.
Example 2: a café lunch (removing GST)
Your team lunch comes to A$68.20 and you need the GST for your records. Step one: A$68.20 ÷ 11 = A$6.20. Step two: A$68.20 − A$6.20 = A$62.00. The meal itself was A$62, with A$6.20 of GST on top.
Example 3: a freelancer's invoice (adding GST)
A graphic designer in Brisbane agrees on A$8,400 for a brand project. GST is A$840, so the invoice total is A$9,240. If she were not registered for GST, she could not add that A$840 at all.
Example 4: a laptop receipt (removing GST)
A small business buys a laptop for A$1,320. Divide by 11 to get A$120 of GST. The price before GST is A$1,200. Provided the business is registered, that A$120 can be claimed as a credit on its Business Activity Statement.
Example 5: using a custom rate
Sometimes you need a different percentage, for instance when comparing with a country that charges 15%. Add 15% to A$1,000 and you get A$150 of tax, for a A$1,150 total. Going the other way, A$1,150 ÷ 1.15 returns A$1,000. The custom option in the tool does exactly this.
Who uses a GST calculator?
More people than you might think. A good GST calculator Aus users can open on a phone is handy for:
- Sole traders and tradies pricing jobs on site.
- Online sellers and market-stall owners working out margins.
- Bookkeepers checking supplier invoices before lodging a BAS.
- Landlords and property managers sorting out which charges carry GST.
- Shoppers who simply want to know how much of a price is tax.
- Students learning basic accounting.
If you only need a quick answer, the GST Calculator Australia tool above gives you the price, the GST and the total in one click.
Common GST mistakes to avoid
- Taking 10% off a GST-inclusive total. Divide by 11 instead.
- Charging GST on GST-free items. Basic food is the classic trap for café and grocery sellers.
- Mixing inclusive and exclusive figures. Check every line of a quote before you add it up.
- Ignoring the A$75,000 threshold. Cross it and you must register, usually within 21 days.
- Claiming credits with no tax invoice. For purchases over A$82.50, you generally need one.
- Rounding too early. Round at the end of an invoice, or follow your software's method consistently.
One extra note for online shoppers: since 2018, GST also applies to many low-value goods imported from overseas, and the seller or platform often collects it at checkout.
Important notes and disclaimer
This website is a general calculation aid. It is not tax, legal or financial advice. Rules about registration, GST-free supplies and credits can change and depend on your circumstances. Before you lodge anything, check the ATO or ask a registered tax agent. Results from this GST Calculator Australia page are rounded to the nearest cent and may differ by a cent from your accounting software.
Summary
Australian GST is a flat 10%. To add it, multiply by 0.10 or by 1.1. To remove it from a total, divide by 11 to find the GST, or by 1.1 to find the price before GST. Keep an eye on the A$75,000 threshold, GST-free items and tax invoices. When you want a fast, error-free answer, the GST Calculator Australia tool at the top of this page does the sums and shows the formula.
Frequently asked questions
What is the GST rate in Australia?
The GST rate in Australia is a flat 10% on most goods and services. It does not change between states or territories. Some items, such as basic food and many health and education services, are GST-free, and a few supplies like residential rent are input-taxed. The Australian Taxation Office publishes the official rules.
How is GST calculated on a price?
To find the GST on a price that does not include it, multiply the amount by 0.10. To get the total, add that GST to the original price, or multiply the original price by 1.1. For example, A$200 plus 10% GST is A$20, so the customer pays A$220.
How do you calculate GST when you know the total?
Divide the GST-inclusive total by 11. The answer is the GST portion. Subtract it from the total to get the price before GST. For A$330, the GST is A$30 and the price before GST is A$300. Do not take 10% off the total, because that gives the wrong answer.
How do I calculate GST from the total on a receipt?
Take the final amount on the receipt and divide it by 11 to see how much GST it contains. A A$55 receipt holds A$5 of GST. If you want the pre-GST amount, multiply the total by 10 and divide by 11, which gives A$50 in this example.
Is this GST calculator Aus tool accurate?
Yes. It uses the standard formulas and rounds results to the nearest cent, which is how most invoices are shown. It is built for the 10% Australian rate but also accepts a custom rate. Your own accounting software may round line by line, so totals can occasionally differ by a cent.
Do I have to register for GST?
You must register if your GST turnover is A$75,000 or more (A$150,000 for non-profit organisations). Taxi and ride-sourcing drivers must register no matter how much they earn. Below the threshold, registration is optional. Check the ATO website or speak to a registered tax agent before deciding.
What does GST-free mean?
GST-free means the sale is taxable at 0%. The seller does not add GST, but can still claim GST credits on related business costs. Examples include most basic food, some medical services and many exports. This is different from input-taxed supplies, where no GST is charged and credits usually cannot be claimed.
Is GST included in shop prices?
Yes. Prices shown to consumers in Australia must generally include GST, so the sticker price is the amount you pay. Business-to-business quotes often show prices excluding GST, so look for wording like "plus GST" or "ex GST" before comparing offers.
Can I claim back the GST I pay?
If you are registered for GST and the purchase is for your business, you can usually claim the GST as a credit on your Business Activity Statement. You generally need a valid tax invoice for purchases over A$82.50. Private purchases and some input-taxed items are not claimable.
Does this calculator save my numbers?
No. Every calculation runs in your browser and nothing is sent to a server or stored. The only thing saved on your device is your light or dark mode choice, and only if your browser allows it. Closing or refreshing the page clears your figures.