ACN number: What it is, who needs one, and how to get it
Learn when you need an ACN number, how to apply, and how it helps you run a compliant company in Australia.
Written by Naomi Lai— Small business & finance writer. Read Naomi's full bio
Published Friday 10 July 2026
Table of contents
Key takeaways
- An ACN number is a unique 9-digit identifier issued by ASIC when you register a company in Australia.
- You receive an ACN automatically when you complete company registration, then apply separately for an ABN and any tax registrations your business needs.
- Display your company name and ACN or ABN on public documents like invoices, quotes, contracts, and your website or email footer to meet legal requirements.
- Add your ACN to document templates in your accounting software to save time and stay compliant with display obligations.
ACN basics
An Australian Company Number (ACN) is a unique 9-digit number issued to a company once it’s registered with the Australian Securities and Investments Commission (ASIC) under the Corporations Act 2001. Think of it as your company's official registration number – it confirms your business exists as a legal entity and appears on ASIC's public register.
The ACN is separate from your Australian Business Number (ABN). While the ACN is a 9-digit number, an ABN is a unique 11-digit identifier that makes it easier for businesses and all levels of government to interact. Your ACN identifies your company structure, while your ABN identifies your business for tax and government dealings.
Every company in Australia must have an ACN, and you'll use it on official documents, contracts, and correspondence throughout your company's life. It's a permanent identifier that stays with your company even if you change your business name, directors, or registered office address.
Who needs an ACN?
You need an ACN number if you register a company with ASIC. This includes proprietary limited companies (Pty Ltd), public companies, and special purpose companies like those limited by guarantee.
Sole traders and partnerships operate without an ACN because they aren't registered companies. They use an ABN and may register a business name if they trade under something other than their personal name.
Trusts don't have an ACN either, but if your trust has a corporate trustee – a company that manages the trust – that company will have its own ACN. This is common in family trusts and self-managed super funds where the trustee is a company structure.
Foreign companies operating in Australia receive an Australian Registered Body Number (ARBN) instead of an ACN. The ARBN works similarly but identifies the company as registered overseas.
How do you get an ACN in Australia?
You receive an ACN number automatically when you register a company through ASIC or an authorised service provider. The registration process requires you to make several key decisions about your company structure and governance before ASIC issues your ACN.
Steps to register a company
The company registration process involves several important decisions that will affect how your business operates. Here's what you need to complete:
- Choose a company name or decide to use your ACN as your company name (for example, "123 456 789 Pty Ltd")
- Decide on governance rules – either adopt ASIC's replaceable rules or create a company constitution
- Set your registered office address (where ASIC sends official documents) and principal place of business
- Appoint at least one director and, if required, a company secretary
- Determine your share structure and identify initial shareholders
- Lodge your application through ASIC's online portal or an authorised agent
- Pay the ASIC registration fee
- Receive your ACN and certificate of registration
The ASIC company registration page provides detailed guidance on each step and current fee schedules.
How much does it cost to register an ACN?
Registering an ACN costs $636 for a standard proprietary company when you apply online through ASIC directly. ASIC updates its fee schedule annually, so check the ASIC fee schedule for the current amount before you apply.
Your total cost may be higher if you use an authorised service provider or registered agent to lodge the application on your behalf. These providers charge their own service fees on top of the ASIC registration fee.
How long ACN registration takes
Most online ACN registration applications are processed within minutes if all information is correct and complete. You'll receive your ACN and certificate of registration electronically, usually on the same business day.
What to do after you get an ACN
Once you have your ACN, you need to:
- Apply for an ABN through the Australian Business Register.
- Register for GST if your business turnover is $75,000 or more, or register voluntarily.
- Open a business bank account in your company name.
- Set up company registers (members, directors, secretaries) and minute books.
- Add your ACN to invoice templates, letterheads, email signatures, and your website.
- Notify ASIC of any changes to company details within the required timeframes.
For more information on getting your business set up with the right identifiers, read this ABN guide.
ACN vs ABN: What’s the difference?
The ACN vs ABN distinction confuses many business owners, but understanding the difference helps you use each identifier correctly.
Your ACN comes from ASIC when you register a company. It identifies your company structure and appears on the ASIC register. You receive it once and it never changes, even if you change your business name or directors.
Your ABN comes from the Australian Business Register (managed by the ATO). It identifies your business for tax purposes and dealings with government agencies. You apply for an ABN separately after company registration, and you can have an ABN without being a company.
A company's ABN is often the same as the ACN but with two extra numbers at the beginning. For example, if your ACN is 123 456 789, your ABN might be 36 123 456 789.
You use your ACN on ASIC documents, company registers, and when you need to identify your company structure. You use your ABN for tax matters, GST registration, business transactions, and most day-to-day business activities.
Both numbers can appear on invoices and business documents, but displaying your ABN usually satisfies the legal requirement to show your company identifier. Many businesses show both for complete transparency.
How do you find your ACN number?
You can find ACN details quickly using free online search tools or by checking your company records. The two main search options are ASIC's organisation and business name registers and the ABN Lookup service.
Find an ACN on ASIC and ABN Lookup
ASIC maintains a searchable register of all Australian companies. Search by company name, ACN, or director name to view basic details, including:
- company name and ACN
- registration date and current status
- company type (proprietary, public, limited by guarantee)
- registered office address
- current and former directors
ABN Lookup also displays ACN details for companies. Search by business name or ABN to see the linked ACN, company type, and GST registration status.
Both services are free and provide instant results. For more detailed company information, ASIC offers paid extract services that show complete company records.
Find your ACN in company records
If you're looking for your own company's ACN, check these common places:
- certificate of registration from ASIC (original or electronic copy)
- annual company statements from ASIC
- company constitution or founding documents
- business invoices, quotes, and receipts
- your website footer or contact page
- email signature blocks
- bank account opening documents
- insurance policies and contracts
Your accountant or bookkeeper will also have your ACN on file in your accounting records. If you need help locating your details, consider working with an accountant or bookkeeper who can help you maintain accurate company records.
Where must you display your ACN or ABN?
You must display your company name with your ACN number or ABN on all public documents and negotiable instruments. This legal requirement helps people identify your company correctly and find your details on public registers.
You can choose to display either your ACN or your ABN on most documents – using your ABN satisfies the display requirement in most situations. Many companies prefer showing their ABN because it covers both the company identification and tax registration requirements.
On invoices and quotes
Every invoice and quote you issue must show your company name and either your ACN or ABN. Place this information prominently in the header or supplier details section where customers can easily find it.
Format the number clearly with a label:
- Australian Company Number (ACN): 123 456 789
- Australian Business Number (ABN): 12 345 678 901
Use consistent formatting across all your sales documents. Most accounting software lets you add these details to invoice templates so they appear automatically on every document you create.
On websites and emails
Add your company name and ACN or ABN to:
- your website footer on every page
- contact us or About pages
- email signatures for business correspondence
- automated email notifications and receipts
This makes it easy for customers, suppliers, and other businesses to verify your company details and check your registration status if needed.
Where you don't need to display your ACN
Not every document your company produces requires an ACN or ABN. ASIC exempts certain internal and informal documents from the display obligation.
You don't need to display your ACN or ABN on:
- internal documents not intended for external parties, such as board meeting agendas and internal memos
- documents exchanged only between the company and its own officers or shareholders
- receipts for amounts under $75 where the payer does not request a tax invoice
- documents that are not negotiable instruments or formal business correspondence
Stay compliant with Xero
Keeping track of ACN display requirements across all your business documents can feel overwhelming, especially when you're managing invoices, quotes, and contracts for multiple clients. Missing your ACN or ABN on important documents could put you at risk of non-compliance with ASIC regulations.
Xero brings your company details together in one place so your invoices, quotes, and financial documents stay consistent and compliant with ACN display requirements. Set up your company information once in your account settings, and it automatically appears on every document you create, saving you time while keeping you compliant.
FAQs on ACN numbers
Here are answers to common questions about ACN numbers, how to find them, and when you need to display them.
What is an ACN number used for?
Your ACN identifies your company as a registered legal entity on ASIC's public register and on official documents such as contracts, invoices, and correspondence. ASIC also uses it to track your company's history, including changes to directors, addresses, and company status over time.
How do I find someone else's ACN?
Search the free ASIC register or use ABN Lookup. Enter the company name or ABN to view basic details, including the ACN, registration date, company type, and registered office address.
Can my ACN change if I rename the company?
No, your ACN stays the same for the life of your company. You can change your company name, directors, registered office, or business activities, but the ACN remains constant. This permanent identifier helps track your company's history on the ASIC register even as other details change over time.
Do trusts or partnerships have an ACN?
Trusts and partnerships don't have an ACN because they're not companies registered with ASIC. However, if a trust has a corporate trustee – a company that manages the trust – that trustee company will have its own ACN. Partnerships and sole traders operate using an ABN and may register a business name, but they don't receive an ACN.
What information does an ACN lookup provide?
A basic ACN search on ASIC's free register shows the company name, ACN, registration date, company type, current status, and registered office address. It also lists current and former directors and company secretaries. For more detailed information, including share structure, charges, and complete company history, you can purchase a paid company extract from ASIC.
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