GST Registration & BAS Lodgment Guide for Australian Businesses (2026–27)

The Goods and Services Tax (GST) is a broad-based tax of 10% on most goods, services, and other items sold or consumed in Australia. Administered by the Australian Taxation Office (ATO), GST registration is mandatory for businesses reaching specific revenue thresholds and voluntary for others wanting to claim input tax credits.

Whether you are a sole trader freelancer, rideshare driver, retail shop owner, or company director, understanding your GST obligations and quarterly Business Activity Statement (BAS) lodgments is essential to avoid severe ATO penalties.

1. When Is GST Registration Mandatory?

Under Australian taxation law, you must register for GST within 21 days if any of the following apply:

1. Standard Businesses: Your current or projected gross business turnover (gross sales minus GST) is $75,000 or more per year.
2. Non-Profit Organizations: Your current or projected annual turnover is $150,000 or more.
3. Taxi & Rideshare Drivers (Uber, Didi, Ola): You must register for GST from your first dollar of turnover, regardless of whether you earn $500 or $50,000 per year.
4. Fuel Tax Credits: You wish to claim fuel tax credits for business equipment or heavy vehicles.

If your annual turnover is under $75,000 (and you do not provide passenger taxi/rideshare travel), GST registration is optional. However, registering allows you to claim GST credits on all business purchases.

2. How 10% GST Works in Practice

When registered for GST, you act as a tax collector on behalf of the Australian Government:

• GST on Sales (Collected): You add 10% GST to your taxable sales and invoices, collecting it from your clients.
• GST on Expenses (Input Tax Credits): You claim a credit for the 10% GST included in the price of legitimate business purchases (e.g. equipment, wholesale inventory, software, office supplies).
• Net GST Payable / Refundable: At the end of each reporting period, you calculate the difference:

$\text{Net GST to ATO} = \text{GST Collected on Sales} - \text{GST Credits Claimed on Purchases}$

If GST collected exceeds credits claimed, you pay the difference to the ATO. If credits exceed collected GST, the ATO refunds you in cash!

3. GST Calculation Formulas

• Adding GST to a Price: $\text{Price with GST} = \text{Price Exclusive of GST} \times 1.10$
• Extracting GST from a Total (Inclusive) Price: $\text{GST Component} = \frac{\text{Price Inclusive of GST}}{11}$
• Calculating the Pre-GST Price: $\text{Price Exclusive of GST} = \text{Price Inclusive of GST} \times \frac{10}{11}$

Example:

If you bill a corporate client $5,500 including GST:

• The pre-tax fee is $5,000.
• The GST collected is $5,500 / 11 = $500.

4. Quarterly BAS Lodgment Cycles & Due Dates

Most small-to-medium Australian businesses report and pay their GST quarterly via a Business Activity Statement (BAS):

Note: If you lodge your BAS electronically through a registered BAS agent or Tax Agent, you generally receive an additional 4-week extension on lodgment and payment deadlines.

5. GST-Free vs. Input Taxed Supplies

Not all transactions in Australia incur 10% GST:

• GST-Free Items: Basic food and groceries, most education and medical services, childcare, exports of Australian goods, and eligible charitable activities. (You do not charge GST, but can claim GST credits on purchases).
• Input Taxed Items: Residential rent, bank fees, and financial loans. (You do not charge GST, and cannot claim GST credits on related purchases).

6. Calculate GST & BAS Figures Instantly

Accurately calculate GST additions, extractions, and quarterly BAS balances using our free Australian tax tools:

• GST Calculator Australia — Add or remove 10% GST with one click.
• BAS GST Calculator — Calculate quarterly GST collected vs credits claimed and net ATO liability.
• GST Registration Calculator — Check if your business turnover triggers mandatory GST registration.