ABN Lookup Tool
Check ABNs on the Australian Business Register. Not an integrated lookup.
About This Tool
An Australian Business Number (ABN) is a unique 11-digit identifier issued by the Australian Business Register (ABR) to businesses operating in Australia. The ABN system was introduced alongside GST in 2000 to simplify business dealings with government and other businesses. Every business entity — whether a sole trader, partnership, company, or trust — needs an ABN to operate legally and issue tax invoices.
Why This Matters for Australian Businesses
Verifying a supplier's or contractor's ABN before making payment is not just good practice — it has direct tax consequences. If a supplier does not quote a valid ABN on their invoice, you are required to withhold 47% of the payment amount and remit it to the ATO under the no-ABN withholding rules. Checking ABN details also confirms whether the entity is registered for GST, which determines whether you can claim input tax credits on their invoices.
Key Rules & Thresholds
- ABNs are exactly 11 digits and include a built-in check digit — invalid numbers are rejected before lookup
- The no-ABN withholding rate is 47% of the total payment amount
- GST registration status shown in ABN lookup tells you whether the entity charges GST
- Cancelled ABNs may indicate a business has ceased trading or been deregistered by the ATO
- ABN lookup is free and publicly available through the Australian Business Register
- Businesses can hold an ABN without being registered for GST — they are separate registrations