Australia ABN & GST Validator (ABR Lookup)

How Australian ABN, GST, and ABR verification works

In Australia, goods and services tax is GST at 10%, administered by the Australian Taxation Office (ATO). Trading entities, companies, partnerships, and sole traders are identified by an 11-digit Australian Business Number (ABN) in the Australian Business Register (ABR). For invoices and ERP systems the country prefix is AU, for example AU51824753556. The number uses the official Modulus 89 checksum.

Australia is outside the European Union, so an Australian business number cannot be checked in EU VIES. VIESAC queries the ABR, confirms whether the ABN is Active or Cancelled, and records whether GST registration is present. An active ABN without GST is still a valid business registration. Bulk CSV checks, the REST API, and monitoring use the same ABR lookup.

Questions about Australian ABN and GST numbers

What is an Australian ABN and what is its format?

An ABN (Australian Business Number) is the 11-digit identifier of an Australian business. It is protected by the Modulus 89 checksum. In international invoices it is written with the prefix AU, for example AU 51 824 753 556.

What is the difference between ABN and GST registration?

An active ABN shows that the business is registered. It does not by itself mean the business is registered for GST. GST registration is generally required from AUD 75,000 turnover (AUD 150,000 for non-profits). VIESAC reports both: whether the ABN is active and whether GST registration is present.

What is the difference between an ABN and an ACN?

An ACN (Australian Company Number) is the 9-digit company number issued by ASIC. The ABN is the 11-digit business and tax identifier. For many companies the ACN sits inside the ABN. This tool checks the ABN and shows the ACN when the ABR returns it.

Can I verify an Australian tax number in EU VIES?

No. EU VIES covers EU member states and Northern Ireland. Australian numbers are checked in the Australian Business Register (ABR) of the Australian Taxation Office (ATO). VIESAC runs that lookup and can store an audit PDF.

Does VIESAC support bulk checking for Australian ABNs?

Yes. You can upload Australian counterparties in CSV, call the REST API (/api/v1/validate and /api/v1/audit), or monitor an ABN so a later cancellation or GST change can be picked up on the next check.