The names look almost identical, so it is understandable to pause over which one to use. The difference is about tax information, rather than how professional the document looks.
Think of an ordinary invoice as the payment instructions. A tax invoice carries those instructions plus the information needed to explain the GST treatment of the sale.
Start with registration, then check the sale
Your GST registration is the starting point. An ABN identifies your business; GST registration tells you whether you are in the GST system. They are connected, but they are not interchangeable.
The type of sale also matters. Being registered does not mean every sale automatically attracts GST. GST-free and other treatments have their own rules. Check the treatment of the particular goods or services, especially when the customer or work is overseas.
Two versions of a small project
These examples show a domestic service that would be taxable when supplied by a GST-registered business. They are an illustration of the arithmetic, rather than a recommendation about how to price your work.
- Not registered: a fee of A$500 is invoiced as A$500, with no GST charged.
- Registered, with A$500 agreed exclusive of GST: A$500 fee + A$50 GST = A$550 payable.
- Registered, with A$550 agreed inclusive of GST: A$50 of that total is GST; do not add another A$55.
What the tax invoice needs to explain
The ATO requires enough information to identify the seller and sale, the tax invoice’s purpose and the GST treatment. Make these details easy to read together, rather than hiding a crucial note in tiny print.
- That the document is intended to be a tax invoice.
- Seller’s identity and ABN, and the date of issue.
- What was sold, including quantity where applicable and price.
- GST payable and the extent to which the sale is taxable.
- For a total price of A$1,000 or more, the buyer’s identity or ABN.
Add the details that help payment happen
An invoice number, explicit currency, due date, contact email and clear payment reference make the document easier to use. Some details support the practical payment process even when they are not part of the tax invoice requirements.
If your customer asks you to add GST but you are not registered, you can explain your registration status and send a standard invoice. Changing the heading to satisfy a request does not change your tax position.
When something changes
If you become GST-registered, update your settings before preparing new invoices and confirm how the registration date affects your sales. Do not add GST to old work simply because you have changed a software switch.
If you spot an error in a sent invoice, contact the customer and keep a record of what changed. Your bookkeeper or registered tax agent can help with corrections, adjustment notes and transactions around registration changes.
A little context: this is general information for Australian businesses, not advice for your individual tax or legal position. Tax details were checked against the linked official guidance on 1 November 2026. For decisions about your circumstances, a registered tax agent or qualified adviser can help.