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blog, Starting a Business

What is the Difference Between an ABN and ACN?

Daniel Spencer

9 mins read

Published:

6 June 2025

Updated:

2 July 2025

Still Confused Between ACN and ABN? Here’s What Your Business Really Needs

Starting a business in Australia comes with its fair share of acronyms, and two of the most important ones you’ll come across are ACN and ABN.

In this guide, we’ll unpack the ACN vs ABN debate — what they mean, why they matter, and how to know which one your business needs.

What’s the difference between an ABN and an ACN?

An ABN (Australian Business Number) is a unique 11-digit number issued by the ATO. It’s used to identify your business to the government and community. Whether you’re a sole trader, partnership, trust, or company, you’ll need an ABN to register for GST, invoice clients, and operate legally.

An ACN (Australian Company Number) is a unique 9-digit number issued by ASIC. It’s only required if you’re setting up a registered company. The ACN is used to track your company’s activities, especially for compliance and reporting purposes.

In short:

ABN = for all types of businesses
ACN = only for registered companies

If you’re starting out and unsure which one applies, think about your business structure.
Sole trader? You’ll just need an ABN.
Registering a company? You’ll need both.
Helpful guide - Should you set up a Company or be a Sole Trader?

Who needs an ACN vs ABN?

Understanding who needs an ACN vs an ABN comes down to your business structure.

Business Type	Needs ABN	Needs ACN
Sole trader	✅ Yes	❌ No
Partnership	✅ Yes	❌ No
Trust	✅ Yes	❌ No
Company (e.g. Pty Ltd)	✅ Yes	✅ Yes
Freelancer / Contractor	✅ Yes	❌ No
Not-for-profit company	✅ Yes	✅ Yes

Summary:

ABN is required for anyone running a business in Australia — whether you’re working solo, in a partnership, or operating a full company.
ACN is only required if you’re setting up a registered company through ASIC (like a Pty Ltd). It’s part of your legal compliance and must be displayed on official documents.

How to Start a Business in Australia in 11 Steps (2025)

What information is included in an ACN?

An ACN (Australian Company Number) itself doesn’t contain detailed information — it’s simply a unique 9-digit identifier issued by ASIC to every registered company in Australia.

However, when you search an ACN on the ASIC register, you’ll get access to key company details, including:

Company name
Date of registration
Company type (e.g. proprietary limited)
Registered office and principal place of business
Current status (e.g. active, deregistered)
Names of officeholders and directors

The ACN acts like a digital fingerprint for your company. It helps ASIC and other organisations track compliance, legal status, and official records.

What information is included in an ABN?

An ABN (Australian Business Number) doesn’t embed information within the number itself — but when you look it up on the ABN Lookup register, you’ll see key business details tied to that number.

Here’s what’s typically shown:

ABN status (e.g. active, cancelled)
Entity name (e.g. John Smith or XYZ Pty Ltd)
Trading name(s) (if any)
Entity type (sole trader, partnership, company, trust, etc.)
Date ABN was issued
Business location (state and postcode)
GST registration status and date
ASIC registration (if it’s a company with an ACN)

This info helps identify the structure and legitimacy of a business. It’s especially useful for clients, suppliers, or partners doing business checks.

Summary Table of ACN vs ABN

Feature	ABN (Australian Business Number)	ACN (Australian Company Number)
Purpose	Identifies your business to the government and public	Identifies a registered company with ASIC
Who needs it	All business types (sole traders, partnerships, trusts, companies)	Only companies registered with ASIC (e.g. Pty Ltd)
Issued by	Australian Taxation Office (ATO)	Australian Securities and Investments Commission (ASIC)
Digits	11-digit number	9-digit number
Used for	Invoicing, GST registration, tax purposes, domain registration	Company compliance, legal documents, ASIC tracking
Where it appears	Invoices, business documents, websites	Company letterheads, legal documents, ASIC register

How to find a company’s ACN?

You can find a company’s ACN by searching the ASIC (Australian Securities and Investments Commission) register. It’s a free online tool that lists all registered companies in Australia.

Here’s how:

Go to the ASIC Connect search.
Enter the company name or ABN.
View the results — the ACN will be listed under the company details.

You’ll also find the ACN on official documents like invoices, business correspondence, and legal forms. By law, registered companies must include their ACN on key paperwork, so it’s usually easy to spot.

Where can I find my ABN details?

To check a business’s ABN, use the official ABN Lookup tool provided by the Australian government. It’s free, fast, and publicly accessible.

Here’s how to use it:

Go to abr.business.gov.au
Enter the business name, ABN, or ACN
View details such as:
- Business name and status
- Entity type (sole trader, company, etc.)
- GST registration
- Location and start date

This tool is handy for checking if a business is active, registered for GST, or trading under another name. It helps ensure you’re dealing with a legit business — whether you’re hiring a contractor, signing a deal, or just doing your due diligence.

How to apply for an ACN vs ABN

Here’s how to apply for an ACN and an ABN, depending on your business structure.

Step	ABN (Australian Business Number)	ACN (Australian Company Number)
Who it’s for	Sole traders, partnerships, trusts, companies	Registered companies only (e.g. Pty Ltd)
Where to apply	Australian Business Register (ABR)	ASIC – Australian Securities and Investments Commission
Application cost	Free	ASIC fees apply (starting from $538 for company registration)
Time to receive	Instantly in most cases	Instantly after ASIC approves your company registration
What you need	TFN, business structure details, business address	Company name, officeholder details, address, share structure
Can you apply for both?	Yes – if you’re starting a company, you’ll need to apply for both	Yes – apply for ACN via ASIC first, then ABN via the ABR

Quick tip:

Starting a company? Apply for your ACN first through ASIC, then use it to register for your ABN through the ABR.
Not a company? Just apply for an ABN through the ABR — no ACN needed.

Both processes are online and designed to be straightforward, especially if you have your documents ready.

Hassle-free company registration starts here

Benefits of having an ABN

Having an ABN makes running your business smoother and more professional. Here’s what it unlocks:

Invoice clients properly: You can issue valid tax invoices and get paid without clients withholding tax at the top rate.
Register for GST: If you earn $75,000 or more annually, an ABN is required to register for Goods and Services Tax.
Claim business expenses: You can deduct eligible expenses when lodging your tax return.
Open a business bank account: Most banks require an ABN to set one up.
Helpful guide: Best Banks for Australian Businesses
Get an Australian domain name: You’ll need an ABN to register a .com.au or .net.au domain.
Build credibility: It shows you’re operating a legit business, which helps with trust and partnerships.

In short, an ABN gives your business structure, access to tax benefits, and a more professional edge.

Benefits of an ACN

Having an ACN is essential if you’re registering a company in Australia. Here’s what it enables:

Limited liability protection: Your company becomes a separate legal entity, which helps protect your personal assets if something goes wrong — as long as you follow director duties.
Builds business credibility: An ACN shows you’re officially registered with ASIC, making your company look more trustworthy to clients, investors, and suppliers.
Required for legal compliance: All companies must have an ACN to meet ASIC requirements, file annual reviews, and keep business details up to date.
Used on official documents: You’ll need to display your ACN on invoices, contracts, and company stationery — it’s a legal requirement.
Enables ABN registration for companies: If you’re setting up a Pty Ltd, you’ll need an ACN before applying for your company’s ABN.

In short, an ACN gives your company legal standing, credibility, and access to the benefits of operating as a registered business in Australia.

Where to display your ABN or ACN

If you’re running a business in Australia, it’s important to display your ABN or ACN in the right places, not just for professionalism, but also to meet legal requirements.

For ABN holders (sole traders, partnerships, trusts, companies):

You should include your ABN on:

Invoices and receipts
Quotes and estimates
Business websites and online stores
Purchase orders
Business correspondence (emails, letters)

This ensures clients and the ATO can easily identify your business and reduces the risk of tax being withheld from your payments.

For ACN holders (registered companies only):

If you’re a company, you must display your ACN (or ABN if it includes the ACN) on:

All official company documents, including invoices and receipts
Business letterheads
Emails and printed correspondence
Company website (especially on the contact or about page)
Order forms and quotes
Any documents lodged with ASIC

Tip: If your ABN includes your ACN, you can just list the ABN — no need to show both separately.

In short:

ABN = identify your business for tax and payments
ACN = required for registered companies on legal and formal documents

Tax implications: ACN vs ABN

Aspect	ABN	ACN
Tax registration	Needed to register for GST, PAYG withholding, and other tax obligations	Does not handle tax directly — ACN is for company identification
Lodging tax returns	Used when lodging business tax returns (as a sole trader, trust, or company)	Not used for lodging tax; ACN appears on company paperwork
Tax reporting	Essential for BAS (Business Activity Statement) and tax filings	Supports ASIC reporting, not ATO reporting
Withholding tax	Without an ABN, clients may withhold tax at 47% from payments	Not relevant — ACN doesn’t affect withholding rules
Business deductions	ABN holders can claim allowable business expenses	Company can claim deductions too, but tax reporting links to ABN
GST threshold	Must register for GST if turnover exceeds $75,000/year	Applies to ABN holder; ACN companies must still register via ABN

Key Takeaway: The ABN connects your business to the ATO for all things tax. The ACN doesn’t affect tax directly — it’s about company structure and legal compliance. If you run a company, you’ll use both, but only the ABN handles tax matters.

Can you change ABN to ACN and vice versa?

You can’t directly “convert” an ABN to an ACN or the other way around — because they serve different purposes and are issued by different government bodies.

Switching from ABN to ACN

If you’re a sole trader, partnership, or trust with an ABN and want to become a registered company, here’s what to do:

Register a company with ASIC. You’ll get an ACN once approved.
Apply for a new ABN for the company. This is separate from your sole trader ABN.
Cancel your old ABN (if you’re no longer operating as a sole trader).
Update details with banks, clients, suppliers, and the ATO.

Switching from ACN to ABN-only

If you’re closing your company and want to operate as a sole trader instead:

Deregister your company with ASIC. This cancels your ACN.
Apply for a new ABN as a sole trader via the ABR site.
Update your tax and business registrations (GST, PAYG, etc.) accordingly.

Important:

ACNs and ABNs are not interchangeable.
You may hold both if you’re running a company.
Changing structures affects your legal, tax, and reporting obligations — so it’s smart to get professional advice before making the switch.

Start smart; get the right setup with Sleek

Whether you’re launching a business or registering a company, Sleek makes it easy to get it right from day one. Our company registration services cover everything — from securing your ABN or ACN, to handling the admin so you don’t have to. No jargon, no delays — just fast, expert support tailored to your structure.

Got questions? Chat with our team and we’ll help you start your business the smart way.

Get Your Business Set Up Right

FAQs about ACN vs ABN

Is the ACN the last 9 digits of ABN?

Yes, the Australian Company Number (ACN) is the last 9 digits of the Australian Business Number (ABN). The ABN, which is an 11-digit number, starts with two digits, and the remaining 9 digits are the ACN.

Should I put ABN or ACN in contract?

Companies incorporated under the Commonwealth Corporations Act 2001 are assigned an ACN. If a company’s ACN is different from the last 9 digits of the company’s ABN, include the ACN in the contract.

How do I cancel an ABN or ACN?

To cancel your ABN: