ABN vs TFN vs ACN
Business identifier, personal tax number, company number.
A TFN is your personal tax number, yours for life. An ABN is an 11-digit number identifying a business — a sole trader has both. An ACN is a 9-digit number issued only to incorporated companies. So a sole trader has a TFN and an ABN; a company also has an ACN.
Worked example
Invoicing as a freelancer, you quote your ABN so the client doesn’t withhold tax. You give your TFN to your bank and super fund, never to a client. You’d only ever have an ACN if you registered a company.
Common mistake
Putting your TFN on an invoice. Your TFN is private and belongs to you personally — the ABN is the number that goes on business paperwork.
Grounded in ATO guidance. Figures last checked . General information, not tax advice.
Related terms
ABN (Australian Business Number)
The 11-digit number that identifies your business.
TFN (Tax File Number)
Your personal reference number in the tax system.
Sole trader
The simplest business structure — you and the business are one.
GST-Free vs BAS Excluded vs Input Taxed
Three ways a line can carry no GST — and three different BAS labels.
← Back to the full glossary.
Questions about this term
ABN vs TFN vs ACN: common questions
- Which numbers does a sole trader need — ABN, TFN or ACN?
- A TFN and an ABN. The TFN is your personal tax number, yours for life; the ABN is the 11-digit number identifying the business. An ACN is a 9-digit number issued only to incorporated companies, so a sole trader never has one.
- Which of the three numbers goes on my invoices?
- The ABN. Quoting it lets the client pay you without withholding tax. Your TFN is private and belongs to you personally — it goes to your bank and super fund, never on an invoice or to a client. An ACN appears only if you have registered a company.
- How can I tell an ABN from an ACN by looking at it?
- Count the digits. An ABN has 11; an ACN has 9. A company holds both — its ACN from incorporation and an ABN for business dealings — while a sole trader has only the ABN alongside their personal TFN.
- Do I need an ACN to start freelancing?
- No — an ACN exists only for incorporated companies. Freelancing as a sole trader needs your TFN, which you already have, and an ABN. You would only ever have an ACN if you registered a company, which is a different structure altogether.
Let Fin handle the jargon for you
Connect your bank and Fin sorts your income, expenses and GST automatically — so terms like this just become numbers that are already worked out. Free to start, no card needed.
Get 2Fin free →