Tax Invoice Requirements in Australia: ABN & GST Explained
Written by Naresh, Founder of QWIK INVOICE · Last updated: 26 August 2026
Short version: every Australian invoice needs your ABN, or the person paying you may be forced to withhold 47% of the payment for the tax office. Once your GST turnover crosses $75,000 in any 12-month period, you must register for GST and charge 10% on top of your price. And once a single sale reaches $82.50 including GST, a customer can demand a proper tax invoice — one your accounting has to be able to produce within 28 days.
What every Australian invoice needs, GST or not
- Your Australian Business Number (ABN) — the single most important field, GST-registered or not. Without it, the payer may be legally required to withhold tax from what they owe you.
- Your business name and contact details.
- Your customer's name and address.
- A clear description of the goods or services supplied.
- The date of issue.
- The amount charged, and the total payable.
These fields apply whether or not you're GST-registered. GST registration only changes what gets added on top — it doesn't change the baseline.
Why the ABN matters so much: no-ABN withholding
Australia's Pay As You Go (PAYG) no-ABN withholding rule is the reason ABNs get so much attention on Australian invoices. If you supply goods or services worth more than $75 (excluding GST) to a business and don't quote an ABN on the invoice, that business is generally required to withhold 47% of the payment — the top marginal tax rate — and remit it to the ATO on your behalf, rather than paying you the full amount.
A few situations are exempt from this rule — supplies made in a private/domestic capacity, supplies wholly of a kind input-taxed for GST purposes, or where the supplier is an individual under 18 earning below a set threshold. For any standard freelance or business invoice, though, the practical rule is simple: always quote your ABN.
GST registration — the $75,000 threshold
You must register for GST once your business's GST turnover reaches or is likely to reach $75,000 in a 12-month period ($150,000 for non-profit organisations). Registration is due within 21 days of crossing the threshold. Two things worth knowing:
- It's a rolling test, not a fixed year. You need to track your trailing (and projected) 12-month turnover, not just your position at financial year-end.
- You can register voluntarily below $75,000. Some sole traders do this to claim GST credits on business purchases — but it also means charging GST on every sale, and lodging Business Activity Statements (BAS) regularly.
Below the threshold and unregistered, you simply don't charge GST — and you can't use the phrase "tax invoice" or show a GST amount on your invoices at all.
The $82.50 rule: when a full tax invoice is required
For GST-registered businesses, the ATO's invoicing guidance uses a specific dollar threshold to decide how much detail an invoice needs — and it's based on the request, not just the amount:
| Sale amount (incl. GST) | Requirement |
|---|---|
| Under $82.50 | No tax invoice legally required, even if the buyer asks — though most sellers provide one as standard practice |
| $82.50 or more | The buyer can demand a tax invoice, and you must provide one within 28 days of the request |
| $1,000 or more | Same as above, plus the invoice must show the buyer's identity or ABN |
In practice, sending a complete tax invoice on every sale — regardless of amount — is the simplest policy. It sidesteps the whole question and matches what invoicing software like QWIK INVOICE produces by default.
What a tax invoice needs beyond the basics
Once GST-registered, a compliant tax invoice adds these fields to the standard list above:
| Field | Detail |
|---|---|
| The words "Tax Invoice" | Stated clearly on the document — this is what distinguishes it from a plain invoice |
| Seller's ABN | Required on every tax invoice |
| GST amount | Either shown as a separate line, or a statement that the total price includes GST |
| Extent of taxable sale | If only part of the sale is taxable (mixed supplies), the invoice must show which part |
| Buyer's identity or ABN | Required only once the sale reaches $1,000 including GST |
Worked example
| Business | GST status | What the invoice needs |
|---|---|---|
| Sole trader copywriter, $50,000/year turnover | Not GST-registered (below $75,000) | Standard fields + ABN, no GST line, not called a "tax invoice" |
| Freelance developer, $120,000/year turnover | GST-registered | Standard fields + ABN + "Tax Invoice" label + 10% GST amount |
| Design agency, $45,000 project invoice | GST-registered | Same as above, plus the client's ABN since the sale exceeds $1,000 |
QWIK INVOICE's international invoice generator covers this directly — the Standard (USA / Global) format includes a Tax ID field for your ABN and a single tax rate you can set to 10% (or leave blank if you're not registered), with AUD as a currency option. Add your business details once in Settings, and every invoice after that carries them automatically — open the generator to try it.
Frequently asked questions
Do I need an ABN to invoice in Australia?
You need an Australian Business Number (ABN) to run a business and invoice legitimately in Australia. If you invoice without quoting an ABN, the payer is generally required to withhold tax from the payment at the top marginal rate (47%) and send it to the ATO — so leaving it off doesn't just look unprofessional, it costs your client money and they'll likely ask you to fix it.
When do I need to register for GST?
Once your business's GST turnover reaches $75,000 in a 12-month period ($150,000 for non-profits), you must register for GST within 21 days. Below that threshold, registration is optional — plenty of small sole traders stay unregistered and simply don't charge GST, which also means they can't claim GST credits on their own purchases.
What is the $82.50 rule?
$82.50 (including GST) is the threshold at which a customer can legally demand a full tax invoice from a GST-registered seller, and the seller must provide one within 28 days of the request. Below $82.50, you're not required to issue a tax invoice unless asked — though most invoicing software, including QWIK INVOICE, issues a complete one regardless of amount, which is simpler and avoids the question entirely.
What must a tax invoice for $1,000 or more include?
Once the total is $1,000 or more (including GST), the ATO requires one extra field beyond the standard tax invoice fields: the buyer's identity or ABN. Below $1,000, you only need the seller's details — the buyer's details are optional.
Can I just charge GST if I'm not registered?
No. If you're not GST-registered, you cannot add a GST amount to your invoice or use the words 'tax invoice' — doing so is a false representation to the ATO. An unregistered business issues a plain invoice with no GST component, full stop.
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