If you’re setting up a company in Australia, you’ll come across the term Australian Company Number (ACN) very quickly. It’s a simple concept, but knowing how an ACN works - and how it fits with your ABN, invoices, contracts and compliance - can save you time and prevent mistakes.
In this guide, we’ll break down the ACN in plain English. We’ll cover what it is, who needs one, how to get it, where to find or display it, and the practical ways it appears in your everyday business documents. We’ll also clear up ACN vs ABN (they’re not the same), and share a few compliance tips so you’re set up properly from day one.
ACN Basics: What It Is, Who Gets One, And When You Need It
An Australian Company Number (ACN) is a unique nine-digit identifier issued by the Australian Securities and Investments Commission (ASIC) to every company registered under the Corporations Act. Think of it as your company’s official ID number for corporate law purposes.
You’ll have an ACN if you register a company (for example, a proprietary limited company, often shown as “Pty Ltd”). Sole traders and partnerships do not get ACNs - they don’t exist as separate companies.
As a small business owner, you typically need an ACN when you choose a company structure. Many founders opt for a company because it’s a separate legal entity, which can help limit personal liability and support growth and investment. If you’re still deciding on structure, it’s worth weighing up the differences between operating as an individual or partnership versus a company before you proceed.
Key points about ACNs:
- Issued only by ASIC to companies (not to sole traders or partnerships).
- Uniquely identifies your company in ASIC’s registers and official records.
- Must be displayed on certain company documents (more on this below).
- Is different from your ABN (Australian Business Number), which is used for tax and business dealings.
ACN vs ABN: What’s The Difference For Your Business?
It’s common to mix up ACNs and ABNs, but they serve different purposes.
- ACN: Your company’s corporate identifier issued by ASIC under company law.
- ABN: Your Australian Business Number for dealings with the tax system and other businesses (such as invoicing, contracts and GST registration).
Companies usually have both. When you register a company and then apply for an ABN, your ABN will incorporate your ACN (with two extra digits). That said, you don’t “convert” an ACN to an ABN - they’re separate numbers for different systems.
If you’re comparing structures or naming options, it also helps to understand the difference between a business name vs company name. Your company name (the legal name recorded by ASIC) is different from any business name you register for trading. Both can appear alongside your ACN on documents, but they serve different roles.
How Do You Get An ACN In Australia?
You get an ACN by registering a company with ASIC. The process is straightforward when you know what information is required. In practice, many small businesses choose a lawyer-led service to set up the structure correctly, issue shares, and prepare the core documents tailored to their needs.
Step 1: Decide Whether A Company Structure Is Right For You
Before you register, consider liability protection, co-founders, future investors, and administrative requirements. Many growing businesses choose a company for credibility and scalability, but it’s not mandatory for every venture.
Step 2: Prepare Your Company Details
You’ll need a company name, registered office and principal place of business, details of shareholders and directors, and share structure. If any director usually lives overseas, make sure you meet the resident director requirements (at least one director must ordinarily reside in Australia).
Step 3: Register Your Company With ASIC
When your company is registered, ASIC issues your ACN immediately. You’ll also receive an ASIC Certificate of Registration, which confirms your company’s details. Many founders handle this through a legal service to avoid errors and ensure documents are set up correctly from day one.
If you’re ready to formalise your structure, a lawyer can manage your Company Set Up and prepare the core documents you’ll rely on from the outset.
Step 4: Put Your Company Documents In Place
Every company needs rules for how it operates. You can use the replaceable rules in the Corporations Act, but most businesses opt for a tailored Company Constitution for clarity on decision-making, director powers, issuing shares and more. If you have co-founders or investors, a Shareholders Agreement is also recommended to deal with ownership, exits and dispute resolution.
Step 5: Apply For An ABN And Tax Registrations
Once you have your ACN, you can apply for an ABN, GST registration (if required), and set up payroll if you’re hiring. Your ABN will be linked to your company details, and you’ll use it on invoices and in most day-to-day transactions.
Where To Find And How To Display Your ACN
You’ll commonly need to show your ACN on official company documents. This is about transparency - it helps customers, suppliers and regulators identify who they’re dealing with.
Where To Find An ACN (Yours Or Someone Else’s)
You can locate your own ACN on your registration certificate or via ASIC’s online registers. If you’re doing checks on another business (for due diligence, credit checks or contract preparation), follow this simple process for finding a company’s ACN. It’s an easy way to confirm you’ve got the right entity before you sign anything.
Where To Display Your ACN
Companies generally need to display their ACN (or ABN, in some cases) on:
- Public documents and eligible negotiable instruments.
- Company letterheads and official notices.
- Invoices, purchase orders and receipts.
- Your website’s contact or legal pages (it’s good practice to include it alongside your registered details).
Practical tip: If you include your ABN on a document, you don’t usually need to also include the ACN on that same document - but there are exceptions for certain company documents under the Corporations Act. Many businesses include both for clarity, especially on letterheads and contracts.
Always make sure the company name you display matches your registered company name. If you trade under a different name, list both the company name and the business name together so people can connect the dots. This is where understanding the difference between a business name vs company name helps you keep records consistent.
Using Your ACN In Contracts And Day-To-Day Compliance
Once your company is up and running, your ACN quietly sits in the background on many of your documents. Getting the basics right reduces confusion and supports enforceable agreements.
Contracts And Execution Blocks
When you sign contracts as a company, make sure the party name lists your full company name and ACN (for example, “Example Pty Ltd ACN 123 456 789”). This helps avoid misidentifying the entity - which can cause issues if a dispute arises down the track.
It’s also worth setting up standard signing blocks aligned with signing under section 127 of the Corporations Act. Executing contracts under section 127 can make it easier to prove that the document was properly signed on behalf of the company.
Electronic Signatures And ACNs
Most everyday agreements can be signed electronically. Ensure your execution block clearly identifies the company (including ACN) and the capacity of the signatory (director, sole director and secretary, etc.). If you’re moving away from wet ink signatures, it’s still important to follow your policy for electronic signatures so documents are executed validly.
Invoices And Customer-Facing Documents
On invoices and statements, include your company name and ABN (and ACN as needed). Clear identifiers help customers claim tax credits correctly and reduce back-and-forth with accounts teams.
Websites, Emails And Public-Facing Materials
Adding your company details and ACN to your website footer, email signature and legal pages is a simple credibility boost. It makes it easy for customers and suppliers to check who they’re dealing with and find what they need quickly.
Common Scenarios: Changes, New Entities And ACN FAQs For Small Businesses
“Can I Convert My ACN To An ABN?”
No - they’re different systems. You obtain an ACN by registering a company with ASIC. You obtain an ABN by registering for one after your company exists (or as a sole trader/partnership). Your company will typically have both.
“We Have A New Trading Name - Do We Get A New ACN?”
No. Your ACN is tied to your company, not the business name you trade under. If you change your company name or register a new business name, your ACN remains the same.
“We Added A Director - Does Our ACN Change?”
No. Changes to your officers, shareholdings, addresses or constitution don’t change your ACN. You must notify ASIC of changes within the required timeframe to keep your records accurate, but your ACN stays constant throughout the life of the company.
“We’re Buying Shares Or Bringing In Investors - Will That Affect Our ACN?”
Share transfers and new share issues don’t affect your ACN. What does change is your company’s internal records and ASIC filings. This is where having a solid Company Constitution and clean share records matters. If you’re transferring or issuing shares, it’s also a good time to check whether you need updates to your share register, board resolutions or related documentation.
“What If We Restructure Into A New Company?”
If you wind up one company and register a new one, the new entity will be assigned a new ACN. Similarly, if you’ve been trading as a sole trader or partnership and then move to a company structure, your new company will have its own ACN (your prior business identity didn’t have one). If a trust is involved, remember the trustee company carries the ACN - not the trust itself.
“How Can I Prove We’re Properly Registered?”
Your ASIC Certificate of Registration is your starting point. You can also point customers and suppliers to ASIC’s registers where they can search your company name and ACN to confirm status, directors and other public details.
Set Your Company Up For Success: Practical Tips
Getting your ACN is one part of setting up a company well. A few practical steps now will save headaches later:
- Use your full company name and ACN consistently on templates, letterheads and contracts.
- Adopt a tailored governance document (such as a Company Constitution) to suit your business, especially if you have co-founders or external investors.
- Standardise your execution blocks to align with section 127 so contracts are easy to enforce.
- Keep ASIC details current (addresses, directors, share changes). Your ACN won’t change, but late filings can lead to penalties.
- When you’re ready to formalise a new venture, have a lawyer manage the end-to-end Company Set Up so your structure, shares and records are right from day one.
Key Takeaways
- An Australian Company Number (ACN) is a unique identifier ASIC issues to companies - it’s different from an ABN and is used for company law and public records.
- You get an ACN when you register a company; sole traders and partnerships don’t have ACNs.
- Display your ACN (or ABN where permitted) on company documents such as contracts, invoices and letterheads, and keep your company name consistent across materials.
- List your full company name and ACN in contracts and align execution blocks with section 127 to support valid, enforceable signatures.
- Your ACN doesn’t change when directors, shareholders or business names change - but you must keep ASIC records up to date.
- For a smooth setup, consider a tailored Company Constitution and a professional Company Set Up to get your structure, shares and registrations right.
If you’d like a consultation about ACNs or setting up your company, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no-obligations chat.
