Australia GST Calculator

What is GST in Australia?

The Goods and Services Tax (GST) is a broad-based tax of 10% applied to most goods, services, and other items sold or consumed in Australia. It was introduced on 1 July 2000 under the A New Tax System (Goods and Services Tax) Act 1999, replacing the previous wholesale sales tax. GST is administered by the Australian Taxation Office (ATO) and is similar in structure to VAT systems used in the UK, New Zealand, and most of the European Union.

GST-registered businesses collect GST on behalf of the ATO when they make taxable supplies. They can also claim credits for the GST included in the price of their business purchases (input tax credits). The business pays the net amount (GST collected minus input tax credits) to the ATO via their Business Activity Statement (BAS).

The 1/11 rule for extracting GST

Because GST is 10%, the GST component of a GST-inclusive price is always exactly 1/11 of that price. This is a handy mental arithmetic shortcut. For example: a price of A$110 (inc-GST) contains A$10 GST (110 / 11 = 10). A price of A$550 contains A$50 GST. The formula in full:

• GST component = Gross price / 11
• Net (ex-GST) price = Gross price x 10/11

This is mathematically equivalent to dividing by 1.10, but the 1/11 form is easier to compute mentally.

Who must register for GST in Australia?

You must register for GST with the ATO if your business has a GST turnover of A$75,000 or more in the current or previous 12 months, or if you expect your turnover to reach this threshold within the next 12 months. The threshold is A$150,000 for non-profit organisations. Taxi and ride-share drivers must register for GST regardless of turnover.

You can register voluntarily if your turnover is below the threshold. Voluntary registration makes sense if your customers are other registered businesses (since they can claim back the GST you charge), or if you have significant GST input tax credits to claim on your own purchases. Once registered, you must lodge a BAS (monthly, quarterly, or annually depending on your turnover) and remit any net GST owing.

GST-free supplies in Australia

Some supplies are GST-free (zero-rated), meaning no GST is charged but the supplier can still claim input tax credits. Key GST-free supplies include:

• Basic food: fresh fruit, vegetables, meat, fish, bread, milk, cheese, eggs, and most unprocessed food. Prepared foods, soft drinks, confectionery, snack foods, and restaurant meals are taxable.
• Most exports of goods and services to recipients outside Australia
• Certain medical and health services
• Certain education courses provided by an approved education provider
• Childcare services and certain charitable activities

Some supplies are input-taxed (exempt), meaning no GST is charged and no input tax credits can be claimed. Input-taxed supplies include residential rental, certain financial supplies, and some sales of existing residential premises.

What must an Australian tax invoice show?

If you are GST-registered and the supply is A$82.50 or more (including GST), you must issue a tax invoice when requested by the recipient. A tax invoice must include:

• The words "Tax Invoice" prominently displayed
• The supplier's identity and Australian Business Number (ABN)
• The date of issue
• A brief description of the goods or services supplied
• The GST-inclusive price
• Either the GST amount separately stated, or a statement that the total includes GST

For tax invoices over A$1,000, the recipient's ABN or name must also be shown. Tidybill generates tax invoices that meet ATO requirements. See Tidybill pricing - free plan available.

Business Activity Statements and GST

GST-registered businesses report and pay GST via their Business Activity Statement (BAS). The BAS requires you to report total sales (G1), GST-free sales (G3), export sales (G2), capital purchases (G10/G11), and the resulting net GST owing or refundable. The ATO pre-populates some BAS fields for single-touch payroll, but GST figures generally come from your own records. Quarterly BAS lodgement is the default for most small businesses; monthly lodgement applies for larger businesses or those with a GST refund history.

Using this calculator for invoicing

This calculator gives quick answers for individual amounts. For ongoing invoicing, Tidybill applies GST automatically to each invoice line item, tracks your GST position, and produces compliant tax invoices for Australian businesses. See Tidybill pricing - free plan available.