Free ABN lookup and validation tool. Enter any 11-digit Australian Business Number to check if it is valid using the official checksum algorithm. Verify ABN status, entity name, entity type, and GST registration with the Australian Business Register.
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Enter an ABN to validate and look up
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An ABN is a unique 11-digit identifier issued by the Australian Business Register (ABR). Every business operating in Australia needs one. It's used on invoices, tax returns, and when interacting with government agencies.
An ABN consists of 11 digits, typically displayed as XX XXX XXX XXX. The first two digits are derived from a checksum algorithm, and the remaining nine digits identify the entity. For companies, the last nine digits are the ACN (Australian Company Number).
Validating ABNs on invoices and supplier records helps you avoid paying incorrect entities, ensures you can claim GST credits correctly, and protects against fraudulent invoices. Under Australian tax law, if a supplier doesn't quote a valid ABN, you may need to withhold 47% tax from the payment.
An Australian Business Number (ABN) is a unique 11-digit number that identifies your business to the government and community. It's used for tax and business purposes, including on invoices, when claiming GST credits, and when dealing with other businesses.
ABN validation uses a checksum algorithm (modulus 89). The first digit is subtracted by 1, then each digit is multiplied by a specific weight (10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19). If the sum of all weighted digits divides evenly by 89, the ABN is valid.
You need an ABN if you're carrying on a business in Australia. Sole traders, partnerships, companies, and trusts all need an ABN. It's free to apply via the Australian Business Register (ABR). Without an ABN, other businesses may withhold 47% tax from payments to you.
An ABN (Australian Business Number) is an 11-digit number for all business entities. An ACN (Australian Company Number) is a 9-digit number specifically for companies registered with ASIC. Companies have both an ABN and ACN.
Yes, you can use the Australian Business Register (ABR) at abr.business.gov.au to look up any ABN. It will show the entity name, type, GST registration status, and more. Our tool validates the format and also queries the ABR for entity details when available.
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