How much is GST in Australia, and how is it calculated

If you have ever looked at a receipt in Australia and wondered why the price includes an extra charge, you have already run into GST. So, how much is GST in Australia, and how do businesses actually work it out?

It is a broad-based tax added to the price of most goods, services and other items sold or consumed across the country, and once you understand the rate and the simple formula behind it, calculating it for any sale becomes second nature. In this post, we will break down the rate, the formula behind it, and how registered businesses calculate, report and pay GST.

How much is the GST in Australia?

Australia's Goods and Services Tax sits at a flat 10 percent. This applies broadly to most goods, services and other items sold or consumed in the country, though some things do not attract GST at all, known as GST-free sales.

Unlike income tax, there are no brackets or sliding scales here. Whether you are buying a coffee, hiring a tradesperson, or purchasing office furniture, the rate stays the same at 10 percent on any taxable sale.

Businesses that are registered for GST are the ones responsible for collecting it. Generally, businesses and organisations registered for GST will include GST in the price they charge for their goods and services, and can claim credits for the GST included in the price of goods and services they buy for their business.

In effect, the business acts as a collector on behalf of the government, adding the tax at the point of sale and later passing it on when it lodges its return.

Who needs to register for GST?

Before a business can legally charge or collect GST, it generally needs to register for it with the ATO. Registration is not automatically required from day one, but it becomes mandatory once specific turnover milestones are met:

• The $75,000 threshold: A business or enterprise must register if its annual GST turnover (gross income minus GST) reaches or exceeds $75,000.
• Non-profit organisations: The mandatory registration threshold is higher for non-profits, sitting at $150,000 or more.
• Taxi and ride-sourcing operators: Regardless of turnover, anyone providing taxi travel or ride-sourcing services (such as Uber or DiDi) must register for GST from their very first dollar.
• Voluntary registration: Even if a business turns over less than $75,000, it can choose to register for GST voluntarily. This allows it to claim back GST credits on business expenses, though it also means charging GST on sales.

How do Australian businesses calculate GST?

Once you know the rate is 10 percent, the calculation itself is fairly simple. There are two directions you will typically work in, depending on whether your starting price already includes GST or not.

1. Identify your starting price. Work out whether the amount you have is GST-exclusive (GST not yet added) or GST-inclusive (GST already included).
2. Adding GST to a GST-exclusive price. Multiply the original price by 10 percent, then add that figure to the price to get the final amount.
3. Extracting GST from a GST-inclusive price. Divide the total price by 11 rather than by 10. This works because a GST-inclusive price is really made up of 11 equal parts, ten for the original amount and one for the tax, so dividing by 11 isolates just the tax portion.
4. Cross-check the result. The GST you are liable to pay on a taxable sale is equal to 1/11th of the sale price, so your figure should always match this ratio regardless of how large or small the sale is.

GST calculation example

To see how the One-Eleventh rule works in practice, consider a retail scenario:

Anh runs a small bakery and sells salad sandwiches for $5.50, a price that already includes the tax.

• The breakdown: Out of the $5.50 collected, the business keeps $5.00, while the remaining 50 cents belongs to the government.
• The math: Dividing the GST-inclusive price by 11 ($5.50 ÷ 11) isolates exactly $0.50 as the GST portion.

This exact logic scales up seamlessly to any transaction size, whether you are dealing with a $5.50 lunch item or a $5,500 commercial invoice.

What sales are GST-free or input-taxed?

Not every transaction in Australia attracts GST, so knowing how much GST applies to a specific sale starts with knowing which category that sale falls into.

If your organisation is registered or required to be registered for GST, you will generally be liable to pay GST on your sales, known as taxable sales, unless those sales are GST-free or input-taxed instead.

Categories of sales

Here are the three main classifications for transactions in Australia:

• Taxable sales: The standard case where GST is charged at 10 percent, and the business can claim credits on related purchases, as the GST owed is equal to 1/11th of the sale price.
• GST-free sales: Carries no GST at all, yet the business can still claim credits on the purchases behind them, including basic food items like fruit, vegetables, meat, bread, and plain milk, along with specific education, childcare, health services, and exports.
• Input-taxed sales: Has no GST added, but unlike GST-free sales, the business cannot claim credits on related purchases, covering transactions like the sale or leasing of residential property and financial services such as providing a loan.

A standard grocery shopping trip often shows this mix in action, since fresh produce contributes no GST while a soft drink or magazine on the same receipt is taxed at the full 10 percent.

Should your business use cash or accruals for GST?

Your GST accounting method determines when you report GST on sales and claim GST credits on purchases. The two methods are cash and accruals, also called non-cash accounting.

• Cash basis: Report GST when a customer pays you, and claim GST credits when you pay your supplier. If a customer pays only part of an invoice, you account for the GST on the amount received.
• Accruals basis: Report GST when you issue an invoice or receive payment, whichever happens first. For purchases, you generally account for GST credits when you receive an invoice or make a payment, provided you meet the tax invoice requirements. This can mean reporting GST on a sale before your customer has paid you.

Businesses with an aggregated turnover below $10 million can generally choose either method. Larger businesses generally use the accruals basis, although other eligibility rules may apply.

If your customers often pay late, the cash basis may be easier on cash flow because you generally report GST as payments arrive. Whichever method you use, keep your invoices and payment records up to date so each sale and purchase appears in the correct BAS period.

If you are unsure which method fits your business, our professional online bookkeepers can help you choose one and apply it consistently.

When do businesses report and pay GST through a BAS?

Once GST has been collected, it needs to be reported and paid to the ATO through a Business Activity Statement, commonly known as a BAS. The reporting cycle a business falls into depends largely on its turnover.

• Monthly reporting: required if your GST turnover is $20 million or more, with each BAS due on the 21st of the following month.
• Quarterly reporting: applies if your turnover is below $20 million, with due dates falling on 28 October, 28 February, 28 April and 28 July, depending on the quarter.
• Annual reporting: available if you are voluntarily registered for GST and your turnover is under $75,000, or under $150,000 for not-for-profit organisations.

This tiered system means a small sole trader and a large retail chain experience GST very differently in practice, even though both are working off the same 10 percent rate. The retailer with a $5 million turnover lodges every quarter, while a business turning over $25 million must report every single month, with each BAS due on the 21st of the following month.

What common GST mistakes should businesses avoid?

Managing GST correctly requires vigilance to steer clear of costly errors during BAS preparation. Keeping an eye out for these frequent pitfalls can save you time and ATO penalties:

• Missing the registration window: Crossing the $75,000 turnover mark without registering means you are still technically liable for GST on your sales from the date you should have registered, even if you forgot to collect it from your customers.
• Claiming credits without proper documentation: You cannot claim GST credits on business purchases over $82.50 (inclusive of GST) unless you hold a valid tax invoice from your supplier.
• Mixing up input-taxed and GST-free transactions: Mistakenly charging GST on input-taxed items like residential rent, or failing to treat basic food lines correctly, will distort your final reporting figures.
• Misapplying the calculation formula: Trying to extract GST by taking 10% of a gross invoice total rather than dividing by 11 will leave your BAS calculations mathematically incorrect.

Have employees? Our payroll experts can help keep your PAYG withholding and super in line with your BAS.

Make GST easier to manage

GST becomes easier to manage when you know which sales are taxable, when your business needs to register and how to calculate the amount to report. Clear records of invoices, payments and purchases also help you claim the right GST credits and prepare your BAS accurately.

As your business grows, keeping track of these details can take more time. Our team at CleanSlate can help with GST registration, day-to-day bookkeeping, BAS preparation and lodgement, so you have a clearer picture of what you owe and when it is due. Book a call with our team to discuss what support you need.