Starting a business in Australia means navigating a range of registrations and numbers. Two of the most important—and often confused—are the Australian Business Number (ABN) and the Australian Company Number (ACN). Understanding the difference between these two identifiers is essential for legal compliance and business clarity.
In this article, we’ll break down the purpose of an ABN and an ACN, who needs them, how to apply, and what to display on your official business communications.
What Is an ABN?
An Australian Business Number (ABN) is an 11-digit identifier issued by the Australian Business Register (ABR) and managed by the Australian Taxation Office (ATO). It is used for all business dealings with the government, including tax and GST.
Who needs an ABN?
- Sole traders
- Partnerships
- Companies
- Trusts and non-profits
What does an ABN do?
- Allows you to register a business name
- Enables you to register for GST
- Facilitates issuing tax invoices
- Is used on BAS forms and income tax returns
What Is an ACN?
An Australian Company Number (ACN) is a unique 9-digit number issued by the Australian Securities and Investments Commission (ASIC) when a company is registered. It is a legal requirement for all Australian companies.
Who needs an ACN?
- All companies incorporated under the Corporations Act 2001
- Companies limited by shares, guarantee, or proprietary companies (Pty Ltd)
What does an ACN do?
- Identifies your company in all dealings with ASIC
- Must appear on all company stationery and official documents
- Is used in the public ASIC register to search company information
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Key Differences: ACN vs ABN
| Feature | ABN | ACN |
|---|---|---|
| Issued By | Australian Taxation Office (ATO) | Australian Securities and Investments Commission (ASIC) |
| Number Format | 11 digits | 9 digits |
| Who Needs It | All businesses including sole traders | Companies only |
| Purpose | Tax, GST, business name registration | Company identification and legal compliance |
| Required On | Invoices, BAS, business registration forms | Company documents, legal contracts, ASIC filings |
Can You Have One Without the Other?
Yes. You can have an ABN without an ACN if you’re operating as a sole trader or partnership. However, if you are registering a company, you will be issued an ACN, and then use that to apply for an ABN.
In other words:
- Sole traders: Only need an ABN
- Companies: Need both ACN and ABN
When to Use Each Number
In most cases:
- Use your ABN for tax and invoicing
- Use your ACN on official company documents such as contracts, letterheads, websites, and financial statements
If you’re a company, the ABN is typically your ACN with two additional digits as a prefix.
How to Apply for an ABN or ACN
To apply for an ABN:
- Visit the Australian Business Register (ABR)
- Submit your application online
- You’ll need an active TFN and personal/business details
To register a company and get an ACN:
- Register through ASIC or an authorised provider
- Provide company structure, director details, and proposed company name
- Receive your ACN upon successful registration
Do You Need a Business Name Too?
If you trade under a name that is not your personal name or company name, you must register a business name with ASIC—even if you already have an ABN or ACN.
Register your business name here with Taxopia quickly and affordably.
Final Thoughts: ABN vs ACN Simplified
Understanding the difference between an ABN and ACN is essential for staying compliant and professional in Australia’s regulatory environment. Whether you’re a sole trader or launching a proprietary company, choosing the right structure—and knowing what registration you need—is a crucial step.
Need help? Taxopia specialises in business name registration, company formation, and small business tax advice. We make the entire process fast, affordable, and fully compliant with ASIC and ATO requirements.