An ABN check takes under a minute, costs nothing, and needs no login. Verify any Australian Business Number (ABN) free at ABN Lookup, the public search tool of the Australian Business Register (ABR). Enter the 11-digit number or business name, then read the entity name, ABN status, and Goods and Services Tax (GST) status.
Skipping the check is expensive. Paying a supplier who does not quote a valid ABN forces you to withhold 47% of the payment, per the Australian Taxation Office (ATO). An invalid or cancelled ABN also means denied GST input credits and exposure to shell-company fraud. Verify first, then pay.
What Is an Australian Business Number (ABN)?
An Australian Business Number (ABN) is an 11-digit identifier issued through the Australian Business Register (ABR) and administered by the Australian Taxation Office (ATO). It identifies your business to government, suppliers, and customers. The ABN is public and appears on ABN Lookup; a Tax File Number (TFN) stays private under the Privacy (Tax File Number) Rule 2015.
An ABN is required for most businesses that trade. It appears on tax invoices to validate GST and prevent no-ABN withholding, and it confirms legitimacy to customers and suppliers. It is not a substitute for a TFN, and a business may need both. It also differs from a tax registration certificate, which only confirms enrolment in a specific program such as GST.
Entitlement is limited. Sole traders, companies, partnerships, and trusts carrying on an enterprise all qualify, per the ABR’s ABN entitlement guidance. Employees, apprentices, and hobbyists are generally not entitled.
Why Verify an ABN Before Paying a Supplier?
Verifying a supplier’s ABN prevents 47% no-ABN withholding, protects your GST input credits, and catches cancelled or fake ABNs before money moves. One lookup confirms the entity is registered, active, and GST-compliant. For finance teams, it is the cheapest control against fraud, denied credits, and audit failures.
The commercial risks stack up. Under the ATO’s Pay As You Go (PAYG) withholding rules, a missing valid ABN triggers 47% withholding. 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. Documented checks strengthen vendor due diligence and audit readiness, and they build trust with legitimate partners.
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, the payer must withhold at the top rate, currently 47%, 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.
| Exception | Detail | Source |
|---|---|---|
| Supply $75 or less (excl. GST) | No withholding on the whole supply | ATO PAYG withholding |
| Private or hobby supply | Individual lodges a Statement by a supplier | ATO Statement by a supplier |
| Supplier not carrying on an enterprise | Declared on the Statement by a supplier | ATO Statement by a supplier |
| Wholly input-taxed supply | No ABN required | ATO Statement by a supplier |
| Individual under 18 earning ≤$350/week | Exempt | ATO Statement by a supplier |
The Statement by a supplier form (NAT 3346) lets a supplier declare why no ABN is quoted, such as a hobby or private supply. The payer keeps it on file for five years instead of withholding. If the payer reasonably believes the statement is false, they must still withhold 47%. Separately, GST registration becomes mandatory at AUD $75,000 turnover, covered below.
How Do You Verify an ABN Online at ABN Lookup?
Go to abr.business.gov.au, enter the 11-digit ABN, an Australian Company Number (ACN), or a 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 in real time, free, with no login.
Steps to follow:
- Open the ABN Lookup portal at abr.business.gov.au.
- Search by ABN, ACN, or business name.
- Complete the security check if prompted.
- Read the entity name, type, ABN status, GST status, and state or postcode.
- 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 PAYG and GST positions if the ATO reviews them.
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. The ABR cancels an ABN when its records show no business 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 and historical trading names. For a cancelled ABN, request reactivation or a Statement by a supplier before you pay.
How Do You Check GST Registration Status on an ABN?
ABN Lookup shows Goods and Services Tax (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 invoices. Paying a GST component to a non-registered supplier is a common audit failure, so match the invoice to the lookup.
Registration thresholds are fixed by the ATO.
| Entity type | Mandatory GST threshold | Source |
|---|---|---|
| Businesses | AUD $75,000 turnover | ATO registering for GST |
| Non-profits | AUD $150,000 turnover | ATO registering for GST |
| Registration window | Within 21 days of reaching the threshold | ATO registering for GST |
See the ATO’s registering for GST guidance for detail. The $75,000 figure has applied since GST began on 1 July 2000.
What Is the ABN Format and Checksum?
An ABN is 11 digits, and its leading two digits are check digits validated by a modulus 89 algorithm. 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 them, then divide by 89. A remainder of zero means the format is valid. The trailing 9 digits equal the ACN only for companies, not sole traders, trusts, or partnerships.
Take the valid example 83 914 571 673. Applying the weights after subtracting 1 from the first digit sums to 534, and 534 divided by 89 leaves no remainder, so it passes. Format validation is offline math that catches typos and fabricated numbers instantly. 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.
| Error | Cause | Fix |
|---|---|---|
| Wrong digit count | Copied from the wrong source | Confirm exactly 11 digits |
| Failed checksum | Mistyped or fabricated ABN | Re-enter, then validate at ABN Lookup |
| ACN used as ABN | 9-digit ACN confused with 11-digit ABN | Confirm the correct number type |
| Cancelled ABN treated as active | Business deregistered | Check status at abr.business.gov.au |
What Is the Difference Between an ABN and an ACN?
An ABN is an 11-digit tax identifier the ABR issues to any entity type; an Australian Company Number (ACN) is a 9-digit identifier the Australian Securities and Investments Commission (ASIC) issues to companies only. A company holds both; a sole trader holds an ABN but no ACN. A company’s ABN is usually its ACN plus two leading check digits.
| Feature | ABN | ACN |
|---|---|---|
| Digits | 11 | 9 |
| Issuer | ABR (via ATO) | ASIC |
| Who gets one | Any entity carrying on an enterprise | Companies only |
| Where to verify | ABN Lookup | ASIC registers |
| Relationship | ACN plus two check digits | Standalone identifier |
Source: ABR and ASIC. For a company with no linked ABN, search ASIC Connect rather than 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. Verify suppliers by ABN and 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, and relying on them is no longer reliable.
Three name types matter.
| Name type | What it is | Where verified | Source |
|---|---|---|---|
| Entity (legal) name | Registered legal name of the entity | ABN Lookup | ABR |
| Business name | Trading identity registered with ASIC | ASIC business names register | ASIC |
| Trading name | Legacy unregistered name | Off ABN Lookup from 1 Nov 2025 | ABR trading names notice |
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.
| Result | Likely cause | Action |
|---|---|---|
| No matching record | Mistyped or missing digits | Re-check all 11 digits |
| ABN cancelled | Entity deregistered | Do not transact; request reactivation |
| Not registered for GST | Supplier opted out or below threshold | Do not pay or claim a GST component |
| Search limit exceeded | Too many searches from one IP | Wait, or use the ABR web services |
| Blank or outdated details | ABN newly registered or updated | Retry after 24 to 48 hours |
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 tools for bulk checks; commercial platforms add monitoring and enterprise resource planning (ERP) integration. 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).
| Option | What it does | Source |
|---|---|---|
| ABN Lookup web services | Validate and pre-fill; requires a free authentication key | abr.business.gov.au web services |
| ABN Lookup tool V14 | Excel macro workbook (~352 KB), bulk by ABN or ACN | abr.business.gov.au Tools |
| Name Lookup tool | Bulk search by name | abr.business.gov.au Tools |
| Bulk extract | Full downloadable dataset | abr.business.gov.au |
| ABN refresh | Keeps stored ABN data current | abr.business.gov.au |
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, and you should save the workbook before opening it or the macros error. For automated vendor onboarding, Commenda’s bulk ABN validation API validates suppliers at scale and connects to your ledger through 100+ ERP, API, and custom integrations.
Do Foreign Companies Need an ABN to Operate in Australia?
A foreign company 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. An ABN cannot be obtained on its own; it follows an Australian entity setup. See Commenda’s guides to GST registration for foreign companies and Australian business setup.
How Commenda Helps 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.
