Australian ACN Generator & Validator
Generate valid Australian Company Numbers (ACN) for software testing and development. Validate any ACN using the official weighted checksum algorithm — runs entirely in your browser.
For testing and development only. ACNs generated by this tool are mathematically valid but not registered with the Australian Securities and Investments Commission (ASIC). Do not use them in legal documents, company registration filings, or for any purpose other than software testing and development.
Australian Company Number (ACN)
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No additional info
Sample Australian ACNs
How to use it
- 1Click Generate to produce a random 9-digit ACN formatted as XXX XXX XXX with a valid check digit.
- 2The tool shows the check digit and explains how it was computed from the first 8 digits using weights [8,7,6,5,4,3,2,1].
- 3Switch to the Validate tab, paste any ACN, and the tool checks whether the 9th digit matches the computed check digit.
- 4Sample ACNs are pre-generated on load — copy any of them directly for quick test data.
Common use cases
- Seed a test database with valid-looking ACNs for integration tests on company-registration and compliance forms.
- Validate user-submitted ACNs on the front end before submitting to an ASIC API or backend service.
- Demonstrate the ACN format and check-digit algorithm to developers new to Australian company identifiers.
- Generate test ACNs for UI testing without accessing ASIC's real company database.
- Audit the ACN validation rule in your own code — compare your implementation against this tool's results.
Frequently asked questions
- What is an Australian Company Number (ACN)?
- An ACN is a unique 9-digit identifier assigned by the Australian Securities and Investments Commission (ASIC) to every company registered in Australia under the Corporations Act 2001. It must appear on all public documents and communications issued by the company.
- What is the difference between an ABN and an ACN?
- An ACN identifies a company as a legal entity registered with ASIC. An ABN is a broader business identifier issued by the ATO for tax purposes and is available to all business structures, not just companies. A company typically has both — the ABN for a company is derived by prepending two check digits to the ACN, making it 11 digits.
- How is the ACN check digit calculated?
- Multiply the first 8 digits by weights [8, 7, 6, 5, 4, 3, 2, 1] and sum the products. The check digit is (10 − (sum mod 10)) mod 10. If the result is 10, the check digit wraps to 0. This is the algorithm published by ASIC.
- Are ACNs ever re-used?
- No. Once an ACN is assigned to a company it is never reassigned, even after the company is deregistered. This means a generated ACN that happens to match a deregistered company's number is still a 'real' (registered) number — another reason to use generated ACNs only in isolated test environments.
- Is it safe to use generated ACNs for testing?
- Yes, in isolated test environments. Generated ACNs satisfy the mathematical check but are not registered with ASIC. Any system that validates ACNs against ASIC's live register will correctly reject them as unknown companies. Do not use generated ACNs in legal documents or ASIC filings.
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