Two identifiers with different purposes
An Australian Business Number (ABN) has 11 digits and identifies a business in its dealings with government and other businesses. An Australian Company Number (ACN) has 9 digits and identifies a registered company. A sole trader can have an ABN without having an ACN.
QuickInvoice checks the format of entered identifiers. It does not look them up on the Australian Business Register (ABR), check their checksum or confirm GST registration. Verify the actual number before downloading.
Sources: ABR: what an ABN identifies; ASIC: ACN display and when an ABN may replace it
For a GST tax invoice
The supplier's identity and ABN are required tax invoice information. Do not substitute an ACN for the ABN. Include the correct registered business details and identify taxable and GST-free supplies.
Company identifier requirements can be satisfied by an ABN that includes the ACN in the circumstances described by ASIC. Do not assume every company must print both numbers in all cases. The optional ACN field is available when you need it.
A practical example
A sole trader enters their trading name and 11-digit ABN, leaving ACN blank. A company enters its correct company identity and ABN, adding an ACN where required. Neither should copy a number from an unrelated sample invoice.
Check before exporting
- Confirm the supplier identity matches the business doing the work.
- Use your own ABN and verify your GST registration before charging GST.
- Leave ACN blank if your business does not have one.
- Keep public examples fictional and never treat them as registration evidence.
Choose identifiers by the supplier, not the customer
An ABN is an 11-digit business identifier. An ACN identifies an Australian registered company and has nine digits. A number typed into the right-sized field is not evidence that it belongs to the supplier.
| Supplier | What to check |
|---|---|
| Individual operating as a sole trader | Use the individual's correct business identity and own ABN where applicable. Being a sole trader does not give them an ACN. |
| Australian registered company | Check its registered company name and nine-digit ACN. Use its ABN for GST tax invoice identification; check ASIC's conditions before using the ABN instead of displaying the ACN. |
| Trading name used by a company | A trading or business name is not another company. Make the underlying supplier identity clear and use that entity's identifiers. |
| Partnership or trust | Do not assume a trustee company's ACN identifies the same entity as the supplier ABN. Verify the contracting entity and seek advice if the arrangement is unclear. |
Sources: ABR: what an ABN identifies; ASIC: ACN display and when an ABN may replace it
A field-by-field company example
The bracketed entries are deliberate placeholders, not valid sample registrations. ASIC permits an ABN to replace an ACN on company documents when the ABN contains that company's ACN and is displayed in the required places. Do not simply remove the first two digits of any ABN and assume you have verified an ACN.
| Field | How to complete and verify it |
|---|---|
| Business name | Example Joinery Pty Ltd — use the actual supplier's registered identity, with any trading name clearly associated. |
| ABN | [company's own 11-digit ABN] — confirm the entity match and, separately, its GST registration status. |
| ACN | [company's own nine-digit ACN] — do not enter a business-name registration reference here. |
| Address / contact | Use the supplier's actual correspondence and contact details. ABN Lookup does not provide every contact detail. |
| Client name | Identify the buyer, not the supplier again. Buyer identification is additional information for tax invoices totalling $1,000 or more. |
Sources: ASIC: ACN display and when an ABN may replace it; ATO: tax invoice information and buyer identification; ABN Lookup: check identity and GST status
Verify before copying saved details
- Search ABN Lookup using the supplier's own details. Compare the entity name, ABN status and GST registration dates with the transaction.
- For a company, cross-check its registered name and ACN with ASIC. If you are trading through another entity, establish which entity supplied the work first.
- Enter identifiers without spaces in QuickInvoice. Its format check only counts digits; it is not a live register lookup or checksum check.
- Recheck saved details when the business structure changes. Updating a local profile cannot retrospectively correct PDFs already sent.
Sources: ABN Lookup: check identity and GST status; ASIC: ACN display and when an ABN may replace it
Check the official guidance
These examples explain how the tool works and are general information. Check the requirements for your circumstances.