ABN vs ACN – What’s the Difference and When Do You Need Both?

If you’re starting a business in Australia, you may have come across both ABNs and ACNs and wondered: what’s the difference? And do I need both?

While they sound similar, they serve different purposes and are issued by different government bodies.

An ABN is used for tax and invoicing and is needed by all businesses. An ACN is for companies registered with ASIC. If you run a company, you need both.

In this article, we’ll break down:

• What an ABN is (and who needs one)
• What an ACN is (and who it applies to)
• The key differences between an ABN and ACN
• When you need one or both

What is an ABN?

ABN stands for Australian Business Number. It’s an 11-digit number issued by the Australian Business Register (ABR), which is managed by the ATO.

You need an ABN if you:

• Are a sole trader
• Run a partnership or trust
• Operate a company
• Want to invoice clients, register for GST, or start a business in Australia

An ABN is how your business is identified in the tax system and is used on:

• Invoices
• Business activity statements (BAS)
• GST registration
• Business bank accounts

What is an ACN?

ACN stands for Australian Company Number. It’s a 9-digit number issued by ASIC (the Australian Securities & Investments Commission).

You need an ACN if you:

• Register a company in Australia under the Corporations Act 2001
• Want to operate as a Pty Ltd (private company)
• Plan to register with ASIC to run a separate legal entity

An ACN is like a business registration number used in legal documents, ASIC filings, and official records.

It’s required for:

• Incorporating a company
• Director/shareholder appointments
• Company tax and ASIC compliance

Key Differences: ABN vs ACN

Do I need both an ABN and ACN?

If you’re a sole trader, you only need an ABN.

If you’re registering a company, you’ll receive an ACN from ASIC and then you’ll also need to apply for an ABN for your company.

Here’s a breakdown:

So yes, companies usually need both an ACN and an ABN.

Which one should I apply for first?

If you’re setting up a company, you’ll:

1. Register with ASIC and receive your ACN
2. Then apply for an ABN using your ACN and company details

If you’re a sole trader, you can skip the ACN entirely and just apply for an ABN.

👉 Apply for a sole trader ABN in minutes with Register My ABN - no paperwork, no stress.

ABN vs ACN - Know What You Need

• Sole trader? You only need an ABN.
  
• Starting a company? You’ll need both an ACN and an ABN.
  
• Not sure? If you're unsure whether you should operate as a company or a sole trader, check out our Sole Trader vs Company guide.

Choosing the right structure now will save you admin (and tax headaches) later.