Australia GST and ABN Invoicing: A 2026 Guide

Two registrations, one invoice

Invoicing in Australia hinges on two facts about your business that people routinely conflate: whether you hold an ABN, and whether you're registered for GST. They are separate registrations with separate triggers, and together they decide whether you charge GST, whether your document is a "tax invoice" or just an invoice, and what it legally has to contain.

Get the relationship between them straight and Australian invoicing is genuinely simple. The pivot point is a single number: $75,000.

The $75,000 GST registration threshold

GST registration becomes mandatory once your business turnover reaches $75,000 in a 12-month period — or $150,000 for not-for-profits. A couple of details catch people out.

First, it looks both backward and forward. It's not only "did I earn $75,000 last year?" If your income this month, annualized, would clear $75,000, the ATO expects you to register now rather than waiting for the rear-view total to catch up. A sudden run of work can push you over prospectively.

Second, once you're required to register, you have 21 days to do it. Miss that window and you can end up liable for GST on sales where you never charged it, paying the tax out of your own margin. Below the threshold, registration is optional; some sub-threshold businesses register voluntarily to reclaim GST on their own purchases, but most don't bother.

An ABN is not GST registration

This is the single most common Australian invoicing mistake, so here it is plainly: having an ABN does not mean you're registered for GST.

An ABN (Australian Business Number) is your business's identifier — the number that marks it as a registered entity. GST registration is a separate decision layered on top. You can hold an ABN and not be registered for GST because you're under the threshold, in which case you charge no GST and issue ordinary invoices. GST registration happens as its own step, either when you first apply for the ABN or later when turnover crosses the line.

The ABN identifies you; GST registration determines whether you charge tax. Don't assume one implies the other.

No ABN on the invoice? Your customer withholds 47%

There's a sharp practical incentive to hold an ABN well before you approach the GST threshold. If you invoice a business and don't quote an ABN, that customer is generally required to withhold 47% of the payment and send it to the ATO. On a $1,000 invoice you'd be paid $530, with the rest sitting at the tax office until you sort it out at year-end.

Quoting your ABN on every invoice prevents that withholding. For anyone doing B2B work, an ABN is a practical necessity rather than optional paperwork.

Invoice vs. tax invoice

The label on the document is legally meaningful and depends entirely on your GST status.

• Registered for GST → you issue a tax invoice. It carries GST and specific mandatory fields, and it's what lets your GST-registered customers claim the GST back.
• Not registered for GST → you issue a regular invoice. You charge no GST, and you must not call it a tax invoice or show a GST amount, since doing so implies you're collecting tax you're not registered to collect.

A non-registered sole trader writing "tax invoice" at the top is making a claim that isn't true.

What a compliant tax invoice must include

If you're GST-registered, the ATO requires seven elements:

1. The words "tax invoice", shown prominently.
2. Your identity as the seller.
3. Your ABN.
4. The date of issue.
5. A description of the items sold, including quantity and price.
6. The GST amount shown separately, or a clear statement that the total price includes GST.
7. The extent to which each sale is taxable (relevant when some items are GST-free).

One conditional rule: for sales of $1,000 or more including GST, the invoice must also show the buyer's identity or ABN. Below that, the buyer's details are optional. Miss a required element and the document may not qualify as a valid tax invoice, which can cost your customer their GST credit.

What a compliant tax invoice looks like

For a GST-registered designer billing $2,200 including GST, a valid tax invoice reads roughly:

TAX INVOICE

Brightwork Design: ABN 12 345 678 901
Date of issue: 29 Oct 2026
Billed to: Harbourline Cafe Pty Ltd

Website design: homepage + 4 pages          $2,000.00
GST (10%)                                        $200.00
                                  Total       $2,200.00
(Total includes GST of $200.00)

Because this sale is $1,000 or more including GST, the buyer's identity (or ABN) has to appear — hence the "Billed to" line. GST in Australia is a flat 10%, which keeps the arithmetic simple. The label "TAX INVOICE", the ABN, and the explicit GST amount are what make the document valid.

GST-free vs taxable: not everything attracts GST

Even when you're registered, not every sale carries GST. Australia treats some supplies as GST-free (zero-rated) — most basic food, many health and medical services, some education, and exports, among others. On a GST-free sale you charge no GST but can still claim GST credits on your related purchases, which is why the seventh tax-invoice element ("the extent to which each sale is taxable") exists: on a mixed invoice you have to show which lines carry GST and which don't.

For most service businesses everything is taxable at 10%, but if you sell anything in a GST-free category, don't apply 10% across the board out of habit.

Reporting: the BAS, and whether to register early

GST you collect isn't yours to keep; you remit it to the ATO and report it on a Business Activity Statement (BAS), typically quarterly. The BAS nets the GST you collected on sales against the GST credits you paid on business purchases, and you pay (or are refunded) the difference. Set the collected GST aside as you go — treating it as income is how businesses get a nasty BAS surprise.

That also shapes the voluntary registration decision for sub-threshold businesses. Registering early lets you claim GST credits on your purchases (useful if you're buying equipment or services in volume) but it obliges you to charge 10% (which can make you pricier to consumers who can't claim it back) and to lodge BAS. If most of your customers are GST-registered businesses, voluntary registration often nets out positive; if you sell to consumers, the added 10% may cost more than the credits are worth.

Invoice Australia the right way

Issueable supports ABN and GST fields, the "tax invoice" label, and GST shown as a separate line or GST-inclusive total. Create an invoice that matches your registration status. For the equivalent rules elsewhere, see GST/HST in Canada and VAT in the UK.

The rules above reflect the general 2026 position and are orientation, not tax advice. Confirm your position with the ATO or a registered tax agent, especially around the timing of registration.