ACN vs ARBN vs ABN: What Is the Difference?

If you plan to establish or expand a business in Australia, you will likely encounter three important identifiers: the Australian Company Number (ACN), Australian Registered Body Number (ARBN), and Australian Business Number (ABN). Each serves a different purpose and applies to different business structures. Understanding these identifiers helps you choose the right structure and remain compliant with Australian regulations 

What is an ACN?

An ACN is a unique nine-digit number issued by the Australian Securities and Investments Commission (ASIC) when you register an Australian company. Every Australian proprietary limited company (Pty Ltd) and public company receives an ACN. The number identifies the company throughout its legal life and appears on company documents, invoices, contracts, and official correspondence. 

If you establish an Australian subsidiary, your company will receive an ACN during the incorporation process. 

What is an ARBN?

An ARBN is also a unique nine-digit identifier issued by ASIC. However, it applies to registered bodies rather than Australian companies. If your foreign company register a branch in Australia, you will receive an ARBN instead of an ACN. The ARBN allows the foreign entity to operate as a registered foreign company while maintaining its original legal identity overseas. 

What is an ABN?

An ABN is an 11-digit identifier issued by the Australian Business Register (ABR). Businesses use an ABN when dealing with the Australian Taxation Office (ATO), customers, suppliers, and other government agencies. Many business structures can apply for an ABN, including:

• Australian companies

• Registered foreign companies (branches)

• Representative offices

• Sole traders

• Partnerships

• Trusts

An ABN enables a business to register for GST (where required), issue compliant tax invoices, claim GST credits, and avoid Pay As You Go (PAYG) withholding on many business payments. 

ACN vs ARBN vs ABN: At a Glance

Do you need more than one?

An Australian company will typically have both an ACN and an ABN. Likewise, a registered foreign company operating through an Australian branch will usually hold both an ARBN and an ABN.

The ACN or ARBN identifies the legal entity under Australian corporate law, while the ABN supports taxation and day-to-day business activities. 

Let ABN Australia help you choose the right business structure

Choosing the correct business structure is the first step towards a successful expansion into Australia. Whether you are establishing an Australian subsidiary, registering a branch, or determining which business identifiers you need, ABN Australia can guide you through the entire process. Our team provides expert advice on company formation, branch registration, ABN applications, and ongoing compliance. Contact us today to discuss your expansion plans and let us help you establish your business in Australia with confidence.

Last updated: 10th July 2026

About the Author

Ro Elvinia is ABN Australia's Customer Success and Marketing Manager. She holds a bachelor’s degree in mass communication, majoring in journalism, and also has an academic background in civil engineering. With over a decade of experience in professional writing and a background spanning journalism, Australian immigration, and business services, Ro brings a unique mix of communication and analytical expertise. She works closely with international clients and contributes to ABN Australia's content strategy, helping global businesses stay informed and confident as they navigate the Australian market.