What is ACN (Australian Company Number)?
The Australian Company Number is the 9-digit identifier ASIC issues to every registered Australian company. It must appear on company stationery, websites, and public documents. Companies also have an ABN; the ABN typically incorporates the ACN.
Current Rate (N/A)
N/A — A$571 ASIC registration fee (2025)
Example
When you register a Pty Ltd with ASIC, you receive an ACN like '123 456 789'. Your ABN is then issued as the ACN plus 2 prefix digits.
How ACN (Australian Company Number) works in Australia
The Australian Company Number (ACN) is the unique identifier ASIC assigns to every company registered in Australia. Unlike the ABN, which is issued to all business entities, the ACN is exclusively for registered companies — sole traders, trusts, and partnerships do not have an ACN.
**Format and display rules**
The ACN is 9 digits, usually displayed in three groups of three: 123 456 789. It must appear on all company documents, including: - Company letterhead and stationery - Emails and websites (typically in the footer) - Contracts, invoices, and official correspondence - ASIC documents and forms - Any business name registered with ASIC
This is a legal requirement under the Corporations Act 2001. Failing to display the ACN can result in penalties for the company and its officers.
**ACN vs ABN**
Every company has both an ACN and an ABN. The relationship between them is straightforward: the ABN is constructed by taking the ACN and adding two check digits as a prefix. For example, a company with ACN 123 456 789 might have ABN 51 123 456 789.
- ACN: must appear on company documents and ASIC forms - ABN: must appear on invoices, BAS, and tax documents - Both numbers are publicly visible — ABN on the ABR register, ACN on ASIC Connect
**Registration and fees**
A company is assigned an ACN when it is registered with ASIC. The 2025 registration fee is A$597 for a proprietary company. Once incorporated, the company must pay an annual ASIC review fee: - Small proprietary company: A$65/year (2025) - Large proprietary company: A$1,045/year - Public company: A$1,309/year
The Annual Review is sent by ASIC on the anniversary of incorporation and must be paid within 2 months.
**Deregistration**
When a company is deregistered, its ACN is cancelled. A deregistered company's assets vest in ASIC. Directors should wind up the company properly before deregistering — not just abandon it — to avoid personal liability for unpaid debts.
If you need to look up a company's ACN, use ASIC Connect (asic.gov.au/asic-connect) — the public company register, free to search.
Related terms
The Australian Business Number is an 11-digit identifier issued to businesses by the Australian Business Register. Without an ABN, payers must withhold 47% from your invoice. Required for GST registration, business name registration, and most B2B trading.
A proprietary limited company is the most common Australian business entity. Owners' liability is limited to their share capital, and the company is a separate legal person. Maximum 50 non-employee shareholders. Must have at least one Australian-resident director.
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