ABN vs ACN: what's the difference?
An ACN is the nine-digit number ASIC gives a company when it is registered. An ABN is the 11-digit number that identifies any kind of business for tax. Only companies have an ACN, and most companies have both.
An ACN (Australian Company Number) is a nine-digit number that ASIC gives a company when it registers it. An ABN (Australian Business Number) is an 11-digit number that identifies any type of business – sole trader, partnership, trust or company – for tax and dealings with government. Only companies have an ACN; most companies have both.
ACN – companies only
ABN – any business
Often the same digits
What is an ACN?
An ACN is a company's identity number under corporate law. ASIC issues it the moment it registers a new company, and the number stays with that company until it is deregistered. It shows the company exists as a separate legal entity, so you will find it on the company's certificate of registration, its ASIC records and its official documents.
Sole traders, partnerships and trusts are not companies, so they never receive an ACN. A trust that has a company as its trustee is a common source of confusion: the trustee company has an ACN, but the trust itself does not.
What is an ABN?
An ABN identifies a business for tax and other dealings with government. It is what you quote on invoices so that customers do not have to withhold tax from what they pay you, and it is the number you need before registering for GST. ABN details are public and anyone can check them on ABN Lookup.
For more on how an ABN differs from your private tax file number, see our explainer on ABN vs TFN.
How the two numbers fit together
If you are setting up a company, the order matters. ASIC says you need to get your ACN before you can apply for an ABN and other tax registrations. The company is registered first, then the company applies for its ABN in its own name.
Once both exist, the ABN is normally built from the ACN: the last nine digits of the ABN are the ACN, with two check digits added at the front. Where that is true, ASIC allows the company to use its ABN in place of its ACN on documents.
Sole trader
Partnership
Trust
Company
Which number goes on your invoices?
A company must show its ACN, or an ABN that contains its ACN, on documents such as letters and invoices, along with its name. In practice most companies show the ABN, because it covers both jobs and it is the number customers need for tax. If you are registered for GST, a tax invoice needs your ABN in any case.
A sole trader or partnership simply shows its ABN.
Common questions
Is an ABN the same as an ACN?
No. An ACN identifies a company under corporate law and comes from ASIC. An ABN identifies a business of any kind for tax. A company usually has both, and its ABN usually contains its ACN.
Do I need an ACN as a sole trader?
No. An ACN only exists for companies. As a sole trader you trade under your own name (or a registered business name) and your ABN.
Is a business name the same as an ACN?
No. Registering a business name with ASIC does not create a company and does not give you an ACN. A business name is just a name a sole trader, partnership, trust or company trades under.
Can I use my ABN instead of my ACN?
A company can, as long as the last nine digits of its ABN are its ACN in the same order. That is the case for most companies.
How we can help
Deciding whether to trade as a sole trader or set up a company is the bigger question behind ABN vs ACN. We register the company, its ABN, GST and PAYG together as part of business setup, so the numbers are right from the first invoice. Get in touch or call (02) 9386 0500.