How to Write a GST Invoice: Australian Requirements

Quick Answer: A valid Australian tax invoice must include the words "Tax Invoice", your ABN, the date, a description of what you sold, the GST amount or statement that GST is included, and the GST-inclusive total. For sales under $1,000, an abridged format applies.

Invoicing sounds simple until you receive a call from a client's accounts payable team saying your invoice isn't valid for their records. Or worse, you discover at BAS time that a supplier invoice you've been claiming credits on is missing your supplier's ABN. Getting the format right protects your cash flow and avoids BAS complications.

When You Must Issue a Tax Invoice

If you're GST-registered and make a taxable sale of $82.50 or more (GST-inclusive), you must provide a tax invoice when the buyer requests one. You must provide it within 28 days of the request.

For sales below $82.50, a regular receipt or document is sufficient and it doesn't need to meet tax invoice requirements.

For GST-free sales (fresh food, most medical services, exports), you can issue an invoice but it must clearly show the supply is GST-free, not that it has a zero GST component. The ATO treats these differently on BAS reporting.

Required Fields for a Tax Invoice

Sales of $1,000 or More (GST-inclusive)

A full tax invoice must contain:

1. The words "Tax Invoice" (prominently displayed; "Invoice" alone won't do, and "GST Invoice" is also not sufficient)

2. Your ABN (the seller's Australian Business Number)

3. Date of issue

4. Description of goods or services (specific enough to identify what was supplied)

5. GST amount for each line item or the total GST for the invoice

6. Total price (GST-inclusive)

7. Buyer's identity (the name or ABN of the recipient)

That last requirement surprises people. For sales over $1,000, you must identify who you're selling to. This doesn't mean you need their ABN (though that's common in B2B), but their business name or full name must appear on the invoice.

Sales Under $1,000 (GST-inclusive)

For sales between $82.50 and $999.99 (GST-inclusive), an abridged tax invoice applies. You don't need to identify the buyer. Required fields:

1. Words "Tax Invoice"

2. Your ABN

3. Date of issue

4. Description of supply

5. Either: the total GST amount, or a statement that the total price includes GST

The statement approach is common in retail: "Total price $550.00 (includes $50.00 GST)" or "Total price $550.00 (price includes GST)".

Showing the GST Amount

There are two accepted ways to present GST on a tax invoice:

Option A (line-by-line breakdown):

Each taxable line item shows the GST-exclusive price, the GST amount, and the GST-inclusive price. This is clearest for the buyer and easiest for BAS reconciliation.

Option B (total with GST statement):

Show the GST-inclusive total and then separately state the GST amount. Common in simpler invoices:

Total: $1,320.00 (includes GST of $120.00)

Use our Australian GST calculator to calculate the exact GST amount for any price. For $1,200 ex-GST, multiply by 1.10 to get $1,320.00 inclusive, and the GST is $120.00.

Mixed Invoices (Taxable + GST-Free Items)

If your invoice includes both taxable supplies and GST-free supplies (for example, a health clinic billing for both a Medicare-claimable consultation and a medical report for an insurer), each line must clearly show its GST treatment.

Mixing up line items on a mixed invoice is a common mistake that causes problems at BAS time. Separate taxable and GST-free lines clearly, and if possible, use separate invoice documents for each type.

Digital Tax Invoices

Electronic invoices (including PDF, email, and invoices sent through accounting platforms) are fully valid as tax invoices in Australia. The ATO does not require paper. The invoice just needs to be stored in a retrievable format for at least five years.

If you use Xero, MYOB, or QuickBooks, these platforms generate compliant tax invoices automatically once configured with your ABN and GST status. Review the template to confirm it includes all required fields before sending your first invoice.

What Happens If Your Invoice Is Invalid?

Your client's bookkeeper will reject it. They cannot claim input tax credits without a valid tax invoice. You'll then need to reissue with the missing information, which delays your payment and creates a paperwork trail.

From your side, if you accept a supplier invoice that's missing the supplier's ABN or the words "Tax Invoice", your claim on that purchase may be disallowed in an ATO audit. Keep records tidy and chase up defective invoices before lodging each BAS.

Invoicing for Deposits and Progress Payments

For construction, consulting, and project work, partial invoices are common. A deposit invoice before work starts is still a tax invoice if the supply is taxable. Include all required fields and state clearly it's a deposit. When the final invoice is issued, you can either issue a full invoice for the total (crediting prior payments) or multiple invoices across the project.

The GST point of liability arises at whichever is earlier: when you issue the invoice, when payment is received, or when the supply is made. For most service businesses, it's the invoice date. Read our guide on claiming GST input tax credits to understand how credits flow through on the purchase side.

Sample Tax Invoice Layout

Here's a minimal compliant layout for a $1,000+ sale:

[Your Business Name]

ABN: [Your ABN]

TAX INVOICE

Invoice #: 0042

Date: 5 April 2026

Bill to: [Client Business Name]

Payment due: 19 April 2026

BSB: xxx–xxx Account: xxxxxxxxx

Clear, correct, and everything the ATO requires. Your client's accounts team will process it on first sight. For more on managing your GST obligations, start with how to register for GST in Australia if you're not yet registered.

Key Takeaways

A valid Australian tax invoice must include the words "Tax Invoice", your ABN, the date of issue, a description of what was supplied, the GST amount, and the total price including GST. For sales over $1,000, you also need to identify the buyer.

The most common invoicing errors are missing the ABN, omitting the words "Tax Invoice" (and using "Invoice" or "Receipt" instead), and failing to show the GST amount separately for mixed invoices. Your client's accounts team will reject an invoice with these errors, and you cannot claim credits on a supplier invoice that fails the same test.

Use our Australian GST calculator to calculate the exact GST amount for any price before it goes on an invoice. For $1,500 ex-GST: GST = $150, total = $1,650. Simple to verify, easy to get right every time.

For more on your broader GST obligations, see our guides on registering for GST and lodging your BAS.

For any invoice where you're calculating GST from scratch (rather than using accounting software), our GST calculator gives you the exact figures. Enter $1,500 ex-GST and it confirms the GST is $150 and the total is $1,650 in about two seconds. Getting the number right on the invoice protects your cash flow and makes BAS reconciliation straightforward.

A well-structured invoicing process takes five minutes to set up in any accounting package and prevents a recurring source of BAS complications. Get it right once and it runs on autopilot.