Do I Need an ABN to Invoice?
If you are running a business, you should quote your ABN on invoices. Without one, your business customers may have to withhold a large slice of the payment.
In this answer
- Understand why an ABN matters on invoices
- Learn what withholding means for missing ABNs
- Know when an ABN is and isn't expected
- Find out where to confirm the rules
4 min
Why an ABN belongs on your invoice
An Australian Business Number identifies your business to the people you deal with and to the ATO. If you are carrying on a business, your invoices should quote your ABN as standard. It signals that you are operating legitimately, and it is one of the details a tax invoice requires.
Beyond looking professional, the ABN has a very practical effect on how your customers handle payment. When it is present, they can pay the invoice in full. When it is absent, the rules can force them to hold back part of the payment — which is exactly the friction you want to avoid when you are trying to get paid.
What happens without one
If you supply goods or services to another business and your invoice does not quote an ABN, the payer is generally required to withhold a portion of the payment and send it to the ATO, rather than paying you the full amount. The withholding rate is set by the ATO, and it is high enough to make a real dent in your cash flow.
You may later be able to recover the withheld amount through your tax return, but in the meantime your money is tied up. The simple fix is to have an ABN and quote it on every invoice. If you are unsure whether withholding applies to a particular payment, confirm it with the ATO or your accountant.
When an ABN isn't expected
There are limited situations where a payment is not in the course of an enterprise — for example, a genuine hobby or a private one-off sale — and an ABN is not expected. In those cases the ATO provides a way to declare that the supply is not made in carrying on a business. But the line between a hobby and a business can be blurry, and getting it wrong has consequences. If you are not certain which side of the line you sit on, check with the ATO or your accountant before issuing the invoice.
Putting your ABN to work
Once you have an ABN, include it on every invoice. Our free invoice tools keep a dedicated spot for it, and what to do if you don't have an ABN covers the alternatives.
This is general information only, not tax or legal advice. ABN and withholding rules depend on your circumstances — confirm them with the ATO or your accountant before relying on them.
Key takeaways
- If you run a business, quote your ABN on every invoice.
- Missing the ABN can force your business customer to withhold part of the payment.
- The withholding rate is set by the ATO and can be substantial.
- Genuine hobbies and private sales may not need an ABN.
- Confirm withholding and ABN questions with the ATO or your accountant.
Frequently asked questions
Is an ABN legally required on every invoice?
If you are carrying on a business, you should quote your ABN, and a tax invoice requires it. The practical driver is that omitting it can trigger withholding. Confirm your situation with the ATO or your accountant.
How much can be withheld if I leave it off?
The payer may withhold a portion of the payment at a rate set by the ATO. It is high enough to affect cash flow, so it is best avoided by quoting your ABN.
What if I'm just doing a one-off private sale?
Some private or hobby sales are not made in carrying on a business and may not need an ABN. The hobby-versus-business line can be unclear, so check with the ATO or your accountant.
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