What is the difference between an ABN and an ACN?

An ABN (Australian Business Number) is an 11-digit identifier issued by the ATO that all businesses need for tax and trading purposes. An ACN (Australian Company Number) is a 9-digit number issued by ASIC only to registered companies. If you operate as a Pty Ltd company, you need both — sole traders only need an ABN.

Do I need both an ABN and an ACN?

If you register a Pty Ltd company, yes — you receive an ACN from ASIC when the company is incorporated, and then apply for an ABN from the ATO. If you are a sole trader or partnership, you only need an ABN.

Who issues the ABN and ACN?

The ABN is issued by the Australian Taxation Office (ATO). The ACN is issued by the Australian Securities and Investments Commission (ASIC) when you incorporate a company.

Can a sole trader get an ACN?

No. An ACN is only issued to registered companies (such as a Pty Ltd). Sole traders, partnerships, and trusts do not receive an ACN.

Registration3 min read

ABN vs ACN — What's the difference?

If you're starting a business in Australia, you'll quickly come across two important identifiers: an ABN and an ACN. They sound similar, but they serve different purposes.

What is an ABN?

An Australian Business Number (ABN) is an 11-digit number that identifies your business to the government and the public.

You'll need an ABN if you:

Run a business (as a sole trader, partnership, company, or trust)
Want to invoice customers and get paid properly
Need to register for GST
Want to claim business tax deductions

Your ABN is used across many government systems, including the Australian Taxation Office, and is typically displayed on invoices and business documents.

Think of an ABN as your business identity for tax and commercial purposes.

What is an ACN?

An Australian Company Number (ACN) is a 9-digit number issued to companies when they are registered with the Australian Securities and Investments Commission (ASIC).

An ACN is only required if you are running a company — not a sole trader or partnership.

You'll use your ACN:

On official company documents
When dealing with ASIC
To legally identify your company on business letters, invoices, and websites

Think of an ACN as your company's legal identifier — issued at the moment of incorporation.

Key differences at a glance

Feature	ABN	ACN
Number length	11 digits	9 digits
Who needs it	All business types	Companies only
Issued by	Australian Taxation Office	ASIC
Purpose	Tax & business identification	Legal company identification

Do you need both?

Sometimes — yes.

If you register a Pty Ltd company, you will:

Receive an ACN from ASIC when the company is incorporated
Then apply for an ABN (your ABN will usually incorporate your ACN within it)

If you're a sole trader, you typically only need an ABN — not an ACN.

Quick examples

Freelancer / sole trader → ABN only
Partnership → ABN only
Company (Pty Ltd) → Both ABN and ACN

How our platform handles this

When you register a Pty Ltd company through our platform, we submit your application to ASIC for an ACN. Registering for an ABN is part of your post-registration compliance roadmap, which guides you through the critical first steps — including your ABN application — within the first 7 days.

Final takeaway

ABN = Business identity (for tax and trading)
ACN = Company identity (for legal purposes)

Understanding the difference helps you register correctly and avoid delays when setting up your business.