ABN and ACN on Australian invoices
The difference between an ABN and an ACN, where each number belongs on an invoice, and how to check a customer's ABN yourself.
An Australian Business Number (ABN) is an 11-digit number for a business. The Australian Business Register, run by the ATO, issues it. An Australian Company Number (ACN) is a 9-digit number that ASIC issues to a registered company. A company has both. Sole traders and partnerships have an ABN but no ACN. Your ABN must appear on every tax invoice you issue. You can check any ABN for free on ABN Lookup, which shows the entity name, whether the ABN is active and whether the entity is registered for GST. 4invoices does not check ABNs. It has no link to ABN Lookup, so you enter the customer details and check them yourself.
- ABN has 11 digits and comes from the Australian Business Register.
- ACN has 9 digits and comes from ASIC, for companies only.
- Your ABN is required on every tax invoice you issue.
- ABN Lookup is the free public tool to check an ABN.
How it works
Ask new business customers for their ABN and legal name. This helps when the invoice is for $1,000 or more, because the tax invoice must then show the buyer's identity or ABN.
Check the ABN on ABN Lookup (abr.business.gov.au). Look at the entity name, the ABN status and the GST registration. Do this before you raise a large invoice.
Enter the customer name and ABN in the invoice. Put your own ABN and the words tax invoice on your invoice if you are registered for GST.
Use the ACN only where useful. A company may add its ACN in the footer of a contract or invoice, but the ABN is the number that matters for GST.
Legal references
- A New Tax System (Australian Business Number) Act 1999 - the law that sets up the ABN and the Australian Business Register.
- A New Tax System (Goods and Services Tax) Act 1999 - tax invoice content, including the supplier's ABN.
- Australian Securities and Investments Commission - ACN registration for companies.
- ABN Lookup (Australian Business Register) - free public search of ABNs.
Frequently asked questions
Do I need to put my ABN on every invoice?
If you issue a tax invoice, yes. Your ABN is one of the items the GST law requires. Without it the buyer may have trouble claiming a GST credit.
What is the difference between an ABN and an ACN?
The ABN identifies an enterprise for tax purposes and any business type can have one. The ACN identifies a company as a legal entity and only registered companies have one.
What if a supplier does not give me an ABN?
Businesses that pay a supplier who does not quote an ABN may need to withhold tax from the payment. Ask your tax agent or read the ATO guidance on no-ABN withholding before you pay.
Does 4invoices verify ABNs?
No. 4invoices does not connect to ABN Lookup and does not check whether an ABN is valid or GST-registered. You type the ABN into the invoice and you are responsible for checking it.