If you are setting up a business in Australia, you will quickly encounter two acronyms that sound similar, are often used together, and are one of the most common sources of confusion for new business owners: ABN and ACN.
The short answer: every business needs an ABN. Only companies need an ACN. If you are a company, you need both in that specific order.
Here is everything you need to know about the difference between the two, who issues them, what they appear on, and how to get them.
Table of Contents
- What is an ABN?
- What is an ACN?
- The key differences
- Who needs what
- How to get an ABN
- How to get an ACN
- Where each number appears
- Common mistakes
- Frequently asked questions
What Is an ABN?
An Australian Business Number (ABN) is an 11-digit public identifier issued by the Australian Business Register (ABR) , an authority administered by the Australian Taxation Office.
Purpose
Tax and commercial identification.
Your ABN identifies your business when dealing with:
- The ATO
- Other businesses
- Government agencies
Who Issues It?
The ABR (run by the ATO)
Who Needs One?
Every business entity operating in Australia, including:
- Sole traders
- Partnerships
- Companies
- Trusts
- Non-profit organisations
How Do You Get One?
Apply online at:
- abr.business.gov.au
- register.business.gov.au
Cost
Free
Format
11 digits
Example:
51 824 753 556
What Is an ACN?
An Australian Company Number (ACN) is a unique 9-digit identifier issued by the Australian Securities and Investments Commission (ASIC) when you register a company under the Corporations Act 2001.
Purpose
Company identification.
The ACN establishes and identifies your company as a distinct legal entity, separate from its directors and shareholders.
Who Issues It?
ASIC
Who Needs One?
Only businesses operating as a registered company, including:
- Pty Ltd companies
- Ltd companies
- Other ASIC-registered company structures
Sole traders, partnerships, and trusts do not have ACNs.
How Do You Get One?
ASIC issues an ACN automatically when you register a company.
You cannot apply for an ACN separately.
Format
9 digits
Example:
010 566 737
The Key Differences
| ABN | ACN | |
|---|---|---|
| Full Name | Australian Business Number | Australian Company Number |
| Issued By | ABR (ATO) | ASIC |
| Digits | 11 | 9 |
| Purpose | Tax and commercial identification | Company legal entity identification |
| Who Needs It | All business entities | Only registered companies |
| Cost | Free | Part of company registration ($576) |
| Appears On | Invoices, BAS, business name register | Company documents, ASIC register |
| Public? | Yes (ABN Lookup) | Yes (ASIC register) |
Who Needs What?
Sole Trader
Needs: ABN only
No ACN required.
You and the business are the same legal entity.
Partnership
Needs: ABN only
The partnership registers its own ABN.
No ACN required.
Trust
Needs: ABN
The trustee registers an ABN in the trust's name.
If the trustee is a company, that company has its own ACN.
The trust itself does not have an ACN.
Company (Pty Ltd)
Needs: ABN + ACN
The ACN is issued first by ASIC when the company is registered.
The ABN is then applied for through the ABR.
In practice, the Business Registration Service allows you to obtain both together.
Non-Profit or Charity
Usually:
ABN only
Unless structured as a company, in which case both an ABN and ACN are required.
The Simple Rule
If you have registered a company with ASIC, you have an ACN.
If you run any kind of business, you have an ABN.
Companies have both.
How to Get an ABN
- Go to abr.business.gov.au or register.business.gov.au
- Select Apply for an ABN
- Answer the eligibility questions
- Enter:
- TFN
- Personal details
- Business activity description
- Business address
- Submit and receive your ABN
Cost
Free
See our full guide to ABN registration in Australia for a complete walkthrough.
How to Get an ACN
You cannot apply for an ACN independently.
It is issued automatically when you register a company with ASIC.
Step-by-Step
- Go to register.business.gov.au
- Select Register a company
- Choose:
- Company name
- Company structure (usually Pty Ltd)
- Directors
- Provide your registered office address (must be a real physical street address)
- Specify your share structure
- Pay the ASIC registration fee ($576 in 2025)
- Receive your:
- ACN
- Certificate of Registration
ASIC processes most company registrations within minutes.
Once you have your ACN, apply for your company ABN through the Business Registration Service or ABR.
Where Each Number Appears
ABN Appears On
- Tax invoices
- Business Activity Statements (BAS)
- ABN Lookup
- Business name registrations
- Business bank accounts
- Google Business Profile
- Government grant applications
- Procurement applications
ACN Appears On
- ASIC company registration certificate
- ASIC register
- Official company documents
- Letterheads
- Notices
- Invoices
- Contracts
- Purchase orders
- Documents lodged with ASIC
Important
If your company has an ABN, ASIC generally allows you to display the ABN instead of the ACN on many documents because the company's ABN is derived from its ACN.
Check current ASIC guidance for your specific circumstances.
Common Mistakes
Mistake 1: Using Your Personal ABN for a Company
When you incorporate a company, the company receives its own ABN.
Your personal ABN and company ABN are separate.
Always invoice using the company's ABN when trading through the company.
Mistake 2: Cancelling Your Personal ABN Too Early
If you transition from sole trader to company:
Do not cancel your personal ABN until you are certain it is no longer required.
The two registrations are independent.
Mistake 3: Not Displaying the ACN on Company Documents
Companies must display their ACN (or ABN where permitted) on official correspondence and documents.
Failure to do so can result in ASIC penalties.
Mistake 4: Confusing an ABN With a TFN
Your:
- TFN = private personal identifier
- ABN = public business identifier
Never provide your TFN when an ABN is requested.
Mistake 5: Using a PO Box for a Registered Office
ASIC requires a real physical street address for company registration.
A PO box is not acceptable.
A virtual address from Space Penguin satisfies this requirement from $20/month.
Frequently Asked Questions
Can a Sole Trader Get an ACN?
No.
ACNs are issued only to registered companies.
A sole trader has an ABN but no ACN.
Does a Company Always Need Both an ABN and an ACN?
Yes.
A company receives an ACN when it is registered.
It then requires an ABN to trade, invoice clients, and meet tax obligations.
In practice, operating companies have both.
What Comes First — the ACN or the ABN?
For companies:
- ACN (issued by ASIC)
- ABN (issued by the ABR)
The Business Registration Service allows both to be completed in one workflow.
My Client Is Asking for an ACN but I'm a Sole Trader. What Do I Tell Them?
Explain that sole traders do not have ACNs.
Provide your ABN instead.
Most systems requesting an ACN can also accept an ABN.
How Do I Find My ABN or ACN?
ABN: Search your business name at abr.business.gov.au
ACN: Search your company name via ASIC at asic.gov.au or connect.asic.gov.au
Do I Need Both on My Invoices?
If you operate as a company, include your ABN on invoices.
For some formal company documents, ASIC may also require the ACN.
Check ASIC's current requirements for your specific situation.
Setting up your company? Space Penguin provides ASIC-compliant registered office addresses in Sydney and Melbourne including signed occupier consent letters as standard. From $20/month.