ABN Verification: Verify Australia Tax Registration Number

How Do You Verify an ABN Online at ABN Lookup?

Go to abr.business.gov.au, search by ABN, ACN, or business name, complete the CAPTCHA if prompted, and read the result. The tool returns the entity name, entity type, ABN status, GST status, and main business location, free, in real time, with no login, per the ABN Lookup site. It is the official public view of the ABR, administered by the ATO.

Steps to follow:

1. Open the ABN Lookup portal at abr.business.gov.au.
2. Search by ABN, ACN, or business name.
3. Complete the security check if prompted.
4. Read the entity name, type, ABN status, GST status, and state or postcode.
5. Use advanced search to filter by state, postcode, tax concessions, or deductible gift recipient (DGR) status.

Document each check with the date and result. Records support your Pay As You Go (PAYG) withholding and GST positions if the ATO reviews them.

What Does Advanced ABN Lookup Search Do?

Advanced ABN Lookup search filters results by state, postcode, tax concessions, and DGR status, and its statistical query reports ABNs by location, status, and entity type, per the ABN Lookup tools page (version 9.9.7). Use it to narrow a name search or confirm a charity’s DGR endorsement before you donate or invoice.

What Is an Australian Business Number (ABN)?

An ABN is an 11-digit identifier issued through the ABR and administered by the ATO; it is public, appears on ABN Lookup, and is the Australian tax registration number for trading entities, per the ABR. It identifies a business to government, suppliers, and customers, and it appears on tax invoices to validate GST.

Entitlement does not require incorporation. Sole traders, partnerships, and trusts carrying on an enterprise all get an ABN without forming a company, and incorporation is a separate step only for company-type entities, per the ABR’s ABN entitlement guidance. Employees, apprentices, and hobbyists are not entitled. An ABN also differs from a tax registration certificate, which only confirms enrolment in a specific program such as GST.

What Is the Difference Between an ABN and a TFN?

An ABN is a public 11-digit business identifier shown on ABN Lookup; a Tax File Number (TFN) is a private, lifelong individual identifier that never appears on ABN Lookup. The TFN is protected by the Privacy (Tax File Number) Rule 2015, a binding instrument made under the Privacy Act 1988. It has been in force since 4 March 2015. An ABN is not a substitute for a TFN, and a business may need both.

A tax registration certificate is separate again; it confirms enrolment in a specific program such as GST, not entitlement to an ABN.

Why Verify an ABN Before Paying a Supplier?

One lookup prevents 47% no-ABN withholding, protects your GST input credits, and catches cancelled or fake ABNs before money moves, per the ATO. It confirms the entity is registered, active, and GST-compliant. For accounts payable (AP) teams, it is the cheapest control against fraud, denied credits, and audit failures.

The risks stack up for AP teams onboarding vendors. A missing valid ABN triggers 47% PAYG withholding, per the ATO. A fake or inactive ABN can signal a shell company. A supplier who is not GST-registered cannot charge GST, so claiming credits on their invoice fails an audit. Dated verification records strengthen vendor due diligence and audit readiness.

What Does an Active or Cancelled ABN Status Mean?

Active means the ABN is current and valid for invoices and Business Activity Statements (BAS); cancelled means do not transact until the supplier re-registers or provides a Statement by a supplier. The ABR cancels an ABN when its records show no enterprise is being carried on. Businesses must update ABN details within 28 days of any change or of ceasing to trade, per the ABR.

Applying, updating, and cancelling all happen at the ABR itself; ABN Lookup is read-only. The tool shows current status plus some history, such as GST registration periods. For a cancelled ABN, request reactivation or a Statement by a supplier before you pay.

How Do You Check if a Supplier Is GST Registered?

ABN Lookup shows GST registration status next to the ABN status. An active ABN without GST registration means the supplier cannot charge GST, and you cannot claim input credits on their invoice, per the ATO. Paying a GST component to a non-registered supplier is a common audit failure, so match the invoice to the lookup.

See the ATO’s registering for GST guidance for full detail.

What Is the 47% No-ABN Withholding Rule?

If a supplier does not quote a valid ABN on an invoice for a taxable supply over $75 excluding GST, the payer must withhold 47% of the payment, per the ATO’s no-ABN withholding rule. The 47% is the 45% top marginal rate plus the 2% Medicare levy, per the ATO resident tax rates, effective since 1 July 2017.

Several exceptions remove the obligation.

What Is the Statement by a Supplier Form (NAT 3346)?

The Statement by a supplier form (NAT 3346) lets a supplier declare why no ABN is quoted, such as a hobby or private supply, so the payer can keep it on file instead of withholding. The payer retains it for five years. If the payer reasonably believes the statement is false, they must still withhold 47%, per the ATO.

This form is the lawful alternative to withholding when a legitimate supplier has no ABN entitlement. Request it before paying, not after, and store it with the dated verification record.

What Is the Difference Between an ABN and an ACN?

An ABN is an 11-digit ABR identifier for any entity type; an ACN is a 9-digit identifier the Australian Securities and Investments Commission (ASIC) issues to companies only. A company holds both, while a sole trader holds an ABN but no ACN. A company’s ABN is usually its ACN plus two leading check digits, per the ABR.

An ACN appears on ABN Lookup only if it is associated with an ABN. For a company with no linked ABN, search ASIC Connect instead.

What Is the ABN Format and Checksum?

An ABN is 11 digits, made up of two leading check digits plus a 9-digit identifier, and the check digits are validated by a modulus 89 algorithm, per the ABR ABN format specification. Subtract 1 from the first digit, multiply all 11 digits by the weights 10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19, sum the results, then divide by 89. A remainder of zero means the format is valid.

Take the valid example 83 914 571 673. After subtracting 1 from the first digit, the weighted digits sum to 534. Dividing 534 by 89 leaves no remainder, so it passes. Format validation is offline math that catches typos and fabricated numbers instantly, but it does not confirm registration. A number can pass the checksum yet still be cancelled or never issued, so always finish with a status check at ABN Lookup.

What Changed With Trading Names on ABN Lookup in November 2025?

Unregistered trading names stopped displaying on ABN Lookup from 1 November 2025, per the ABR trading names notice. Verify suppliers by ABN or their ASIC-registered business name instead of a trading name. Trading names were legacy identifiers from before the National Business Names Register launched in 2012. Relying on them is no longer reliable.

What Should You Do When ABN Verification Fails?

Confirm the number first, then decide whether to withhold. Re-enter the full 11 digits without spaces, search by business name if the number fails, and cross-check ASIC for company details. If the ABN is missing, cancelled, or fake, request the correct ABN or a Statement by a supplier. If neither arrives, withhold 47% before paying, per the ATO.

Best practice: check both ABN and GST status, never transact on a cancelled ABN, and store a dated record of every check for audit support.

How Can Finance Teams Verify ABNs in Bulk or via API?

The ABR offers free web services and downloadable Excel tools for bulk checks; match the tool to the volume. A one-off supplier needs the portal; a vendor list of hundreds needs the web services or an integrated application programming interface (API).

The web services need a registered globally unique identifier (GUID) as a developer key. An ACN appears in the Excel tool only if it links to an ABN. Save the workbook before opening it, or the macros error. For automated vendor onboarding, Commenda’s bulk ABN validation connects to your ledger through 100+ ERP, API, and custom integrations.

Do Foreign Companies Need an ABN to Operate in Australia?

A non-resident entity needs an ABN if it carries on an enterprise in Australia or makes supplies connected with Australia, and the same AUD $75,000 GST turnover threshold applies, per the ABR’s entitlement test. Entitlement turns on carrying on an enterprise, not on local incorporation. A non-resident business can apply for an ABN with proof-of-identity documents without forming an Australian company.

Foreign sellers often cross the threshold through Australian fulfilment or logistics partners without realising it. See Commenda’s guides to GST registration for foreign companies and Australian business setup, and the related NZ IRD number verification guide for Pacific cross-border checks.

How We Help With ABN Verification and Australian GST Compliance

Commenda’s global indirect tax software turns ABN verification into one certain step in cross-border supplier due diligence. It runs bulk ABN validation, handles GST registration and filing for Australia, and keeps audit-ready vendor records, all connected through 100+ ERP, API, and custom integrations. Verify tax IDs across borders with the Global Tax ID Verification tool and track filing deadlines with the compliance calendar.

Book a demo to get a free supplier ABN risk check and see your Australian GST obligations handled end to end.