- Your ACN is issued automatically by ASIC the moment your company registration is approved. There is no separate application, no extra step, and no waiting period. If you are trying to get an ACN, what you actually need to do is register a company.
- An ACN identifies your company as a legal entity with ASIC. It is not the same as your ABN, which is used for tax purposes with the ATO. A registered company needs both, and they are issued by two different bodies for two different purposes.
- Displaying your ACN on invoices, contracts, and letterheads is a legal requirement under the Corporations Act 2001, not optional best practice. The only exception is if your ABN is already displayed, since for Australian companies the last nine digits of your ABN are always your ACN.
An Australian Company Number (ACN) is a unique 9-digit identifier that ASIC automatically issues to every company registered in Australia. It’s your company’s official ID under the Corporations Act 2001, used to identify your business in legal documents, ASIC records, and public registers.
If you’re setting up a company in Australia, getting an ACN isn’t a separate step or an optional extra. It happens automatically the moment ASIC approves your company registration, and from that point on, it stays with your company for life.
But knowing what an ACN is and knowing how to use it correctly are two different things. This guide covers everything you need: who gets one, how ASIC issues it, where you’re legally required to display it, and what your obligations are once you have it.
If your company name already includes your ACN as part of its registered name, you do not need to display the ACN separately on public documents.
What is an Australian Company Number (ACN)?
An ACN (Australian Company Number) is a unique nine-digit number issued by the Australian Securities and Investments Commission (ASIC) when you register a company in Australia.
It’s your company’s official legal identifier under the Corporations Act 2001 (Cth), used to track your business on the ASIC register.
It’s important not to confuse this with other registrations:
- ACN: Identifies your company as a legal entity (issued by ASIC)
- ABN / TFN: Used for tax purposes like GST, PAYG, and income tax (issued by the ATO)
If you’re unsure how they differ, read more on What is the Difference Between an ABN and ACN?
An ACN always follows this format:
ACN XXX XXX XXX
The final digit is a check digit, calculated using a specific formula. This ensures every ACN is valid and prevents fake or randomly generated numbers.
Once issued, your ACN is permanent. It won’t change if you:
- Rename your company
- Appoint or remove directors
- Update your business address
- Change your business activities
It remains the single identifier that links your company’s entire ASIC history.
Who needs an ACN in Australia?
Not every business in Australia receives an ACN, it depends on your business structure.
You’ll only get an ACN if you register a company with ASIC.
Businesses that get an ACN
The following entities are issued an ACN upon registration:
- Proprietary limited companies (Pty Ltd): the most common structure for small businesses
- Public companies (Ltd)
- No liability companies (NL)
- Unlimited companies
Businesses that don’t get an ACN
If you’re operating under one of these structures, you won’t receive an ACN:
- Sole traders: you operate under your personal ABN
- Partnerships: the partnership uses an ABN, not an ACN
- Trusts: the trust itself doesn’t have an ACN (but a corporate trustee will have one)
- Incorporated associations: registered at a state or territory level, not with ASIC
Do foreign companies need an Australian Company Number (ACN)?
If you’re an overseas company expanding into Australia, you won’t receive an ACN either.
Instead, ASIC issues an Australian Registered Body Number (ARBN), also a nine-digit number, but used specifically for foreign entities operating in Australia.
This is an important distinction if you’re planning to set up a local presence, as the registration process and compliance requirements differ.
If you’re unsure which structure is right for you, our guide to What Is the Best Business Structure in Australia breaks down the key decision points.
How do you get an ACN in Australia?
The most important thing to understand upfront: you cannot apply for an ACN directly. There is no standalone ACN application form or process.
ASIC issues your ACN automatically as part of approving your company registration, it appears on your Certificate of Registration the moment your application is approved.
So to get an ACN, what you actually do is register a company. Here’s what that involves:
Step 1: Choose your company structure
For most founders, this means a proprietary limited (Pty Ltd) company.
It limits personal liability, is straightforward to set up, and suits the majority of small-to-medium businesses in Australia.
Step 2: Check and reserve your company name
Your company name must be unique on the ASIC register and comply with ASIC’s naming rules. For example, it cannot imply a connection to the government or use restricted words without approval.
You can use Sleek’s company name checker to quickly see whether your preferred company name is available before lodging your registration.
Step 3: Ensure all directors have a Director ID
This is a compliance gate that catches a lot of first-time founders off guard.
- Before you lodge your company registration, every director must have a Director Identification Number (DIN) issued by the Australian Business Registry Services (ABRS).
- Without it, your Form 201 lodgement will be rejected. You can apply via myID.
Step 4: Appoint at least one Australian-resident director
A proprietary company must have at least one director who ordinarily resides in Australia. This is a legal requirement under the Corporations Act, not just a recommendation.
Step 5: Set a registered office address
- Your company needs a physical address in Australia as its registered office, the address where ASIC will send official correspondence. PO boxes are not accepted.
- If you don’t have a physical premises, a registered business address service covers this requirement.
See our guide on registered office vs principal place of business if you need help understanding the difference.
Step 6: Lodge Form 201 via the Business Registration Service
The Business Registration Service is the single portal where you can:
- Register your company,
- Apply for an ABN, and
- Complete tax registrations in one transaction.
You can lodge Form 201 here along with your company details and pay the ASIC registration fee.
Cost and timeline
- ASIC registration fee: $611 (subject to annual changes)
- Processing time:
- Usually within a few hours
- Can take up to 48 hours
Once approved, you’ll receive your Certificate of Registration, which includes your ACN.
Most founders assume their ACN and ABN are two separate numbers to track. In practice, for Australian companies, the last nine digits of your ABN will always match your ACN. This means displaying your ABN on invoices and contracts simultaneously satisfies your ACN display obligation under the Corporations Act.
Where do you need to display your ACN?
Getting your ACN is one thing, using it correctly is another.
Many company directors don’t realise that displaying your ACN isn’t optional. It’s a legal requirement under the Corporations Act 2001, and failing to comply can result in penalties.
Where your ACN must appear
Your company must display its ACN (or ABN, if it includes the ACN) on all public-facing documents and formal records, including:
- Invoices and receipts
- Contracts and agreements
- Letterheads (both physical and digital)
- Order forms
- Cheques and promissory notes
- Documents lodged with ASIC or the ATO
ACN Format requirements
Your ACN must always:
- Be preceded by “ACN”
- Follow the standard format: ACN XXX XXX XXX
Common mistakes that make your document non-compliant:
- Dropping digits
- Combining the number into one string
- Leaving out “ACN” entirely
Do you need to display your ACN if you have an ABN?
In most cases, no and this is where many businesses get confused.
If your company displays its ABN, you don’t need to show the ACN separately as long as the ABN includes it.
For Australian companies, it always does.
That’s because:
- Your ABN is 11 digits
- The last 9 digits are your ACN
How do you check an ACN in Australia?
An ACN is a public identifier, which means anyone can use it to look up a registered company in Australia.
This transparency is intentional, it helps businesses verify who they’re dealing with and reduces the risk of fraud.
How to search an ACN
You can look up a company in seconds using these official tools:
- ASIC Connect
Search by company name or ACN to access official registration details - ABN Lookup (free)
A quick way to view a company’s ABN and ACN together
A basic ACN search will show:
- Company name
- Registration status (e.g. registered, deregistered)
- Date of registration
- Registered office address
- Names of current officeholders (directors, secretaries)
When should you run an ACN search?
An ACN search is a simple but powerful due diligence step.
You should use it before:
- Signing contracts
- Onboarding new suppliers or partners
- Making large payments to an unfamiliar business
It takes less than a minute and can help you avoid dealing with:
- Deregistered companies
- Incorrect entities
- Potentially fraudulent businesses
For more detailed records, historical officeholders, document history, or a formal extract for legal purposes, you’ll need an ASIC company extract. See our guide on how to obtain an ASIC company extract.
What are your ongoing ASIC obligations after getting an ACN?
Receiving your ACN and Certificate of Registration is the starting line, not the finish line. Once your company is registered, you take on a set of ongoing legal obligations with ASIC.
Key obligations to know:
1. Notify ASIC of changes within 28 days
Any change to your company’s directors, registered office address, principal place of business, or shareholder details must be reported to ASIC within 28 days. Miss the deadline and you’ll face late fees and a compliance flag on your record.
2. Pay the ASIC annual review fee
Every year, on the anniversary of your company’s registration date, ASIC sends an annual review notice. You’ll need to review your company details, confirm or update them, and pay the annual review fee to keep your registration active. The amount varies by company type and is indexed annually.
Read more: ASIC Annual Review Fee (2026): Costs and Due Dates
3. Maintain your registered office
Your registered office must remain a valid, physical Australian address at all times. If you move, update ASIC promptly.
4. Director ID obligations for new directors
Any director appointed after your company’s registration must obtain their Director ID before being formally appointed. This is an ongoing requirement, not just a setup-stage one.
What are the most common ACN mistakes?
Most ACN-related problems aren’t complicated, they’re the result of a few easily avoidable missteps. Here are the ones that come up most often.
1. Trying to apply for an ACN separately
There’s no standalone ACN application. If you’ve been searching for one, stop, register your company through the Business Registration Service and your ACN will be issued automatically.
2. Not getting a Director ID before lodging Form 201
The Business Registration Service will reject your application if any director is missing a DIN. Get all Director IDs sorted through ABRS before you begin the registration process, not after.
3. Using a PO box as your registered office
ASIC requires a physical street address. A PO box will get your application rejected. If you don’t have a physical premises, use a registered business address service.
4. Forgetting to display the ACN on company documents
Non-display is a strict liability offence under the Corporations Act. It doesn’t matter if the omission was accidental, update your invoice and letterhead templates as soon as your ACN is issued.
5. Assuming your ACN is also your ABN
They serve different purposes and are issued by different bodies, your ACN identifies your company with ASIC, while your ABN is used for tax and business transactions. A company needs both.
Backdating your ACN is not possible. ASIC issues it on the date your company registration is approved, and that date is fixed permanently on the ASIC register. If you have been trading informally before registering and need to establish when your company officially came into existence, the registration date on your Certificate of Registration is the only legally recognised starting point.
Need help registering a company in Australia?
Your ACN is issued when you register a company and Sleek makes the entire process simple, fast, and fully compliant.
- Company registration: We handle your ASIC company registration end-to-end, so your business is ready to launch without delays.
- Ongoing ASIC Compliance : From annual reviews to lodgements, we help keep your business compliant and avoid unnecessary penalties or missed deadlines.
- All-in-one business support: From accounting and tax to bookkeeping and payroll, Sleek keeps your finances and ATO obligations on track, all under one roof.
- Transparent Pricing: Every service comes with clear, upfront pricing. No hidden fees, no surprises.
Ready to get your ACN? It starts with registering your company and Sleek makes that the easiest part of launching your business.
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Frequently Asked Questions
What happens to my ACN if my company is deregistered?
The ACN does not disappear, it remains on the ASIC register as part of your company’s permanent history. However, once deregistered, the company ceases to exist as a legal entity and the ACN can no longer be used for trading, banking, or contracting purposes.
How long does it take to get an ACN after registering?
For online applications lodged via the Business Registration Service with all information correct, ASIC typically issues the ACN within a few hours. In some cases it can take up to 48 hours.
Does an ACN expire?
No. An ACN does not expire and has no renewal requirement of its own. It remains valid for as long as your company is registered with ASIC. If your company is deregistered, the ACN becomes inactive but remains on the ASIC register as part of your company’s historical record.
