How to Find Your Tax File Number (TFN) in Australia

Your Tax File Number (TFN) is a unique 9-digit identifier issued by the Australian Taxation Office. Once issued, it is yours for life; it never changes, even if you change your name, move interstate, or change jobs. The most common reason people search for their TFN is that they need it for a new job, a bank account, or a super fund, but cannot remember where it is.

7 Places to Find Your Tax File Number

Lost Your Tax File Number? How to Recover It

If none of the above methods works, you do not have myGov linked, you have no prior returns, and you do not have a tax agent, the ATO can confirm your TFN directly:

• 
  Call the ATO: phone 13 28 61 (individuals line, Monday to Friday 8 am-6 pm). You will need to verify your identity using your personal details (date of birth, address, etc.). The ATO will not give you the TFN over the phone, but will post a letter to your registered address
• 
  ATO online: if you cannot log into myGov, you can also use the ATO’s online identity verification service to request your TFN. The ATO will send it to your address of record within 28 days
• 
  Your tax agent: the fastest recovery method if you have an established relationship. Your agent can look up your TFN from their client file, verify your identity, and provide it to you directly, without waiting for ATO post

Important: never ask for your TFN to be sent by email or unsecured message. The ATO will not do this, and scammers impersonating the ATO sometimes ask for TFN details via email or SMS. The ATO communicates about TFNs by post or through secure channels (myGov, ATO app).

What Is a Tax File Number and What Is It Used For?

Your TFN identifies you to the Australian tax system. It is different from your ABN (Australian Business Number, for business activities) and from your ACN (Australian Company Number, for companies). Most individuals only need a TFN; you need an ABN only if you operate a business or work as a contractor.

Your TFN is used:

• 
  By your employer to withhold the correct amount of tax from your wages via PAYG withholding
• 
  By your bank to withhold tax on interest payments at the correct rate
• 
  By your super fund to process contributions correctly
• 
  By the ATO to link your income, tax, and super records
• 
  On your tax return, identify your annual lodgment

If you start a new job and do not provide your TFN within 28 days, your employer is required to withhold tax at the top marginal rate (45% plus Medicare Levy = 47%) rather than your actual marginal rate. Providing your TFN promptly prevents unnecessary over-withholding.

When You Must and Must Not Provide Your TFN

Your TFN is not required in every financial transaction. Knowing when it is legally required (and when it can’t be demanded) protects your privacy:

How to Apply for a TFN (If You Don’t Have One)

Most Australian residents receive a TFN when they first lodge a tax return or join the workforce. If you have never had one:

• 
  Australian residents: apply online through the ATO’s website. The TFN is typically issued within 28 days
• 
  Foreign passport holders: apply at an Australia Post outlet with an ATO application form and your foreign passport. TFN issued within 28 days
• 
  Working holiday visa holders: apply online via the ATO website with your visa details. You need a TFN to work legally in Australia
• 
  New businesses and ABN applicants: if you are registering for an ABN for the first time, the ABN application also links to your TFN

If you have a myGovID (digital identity set up through the myGovID app), you can apply for a TFN online and receive it in real time through ATO Online Services, the fastest method available.

TFN and Your Tax Return

Your TFN is required on every tax return. If you lodge through a registered tax agent, they use your TFN to submit your return to the ATO. If you lodge via myTax yourself, the system pre-fills your TFN.

For the 2025-26 financial year, individual tax returns can be lodged from 1 July 2026 via myTax. The self-lodge deadline is 31 October 2026. Registering with a tax agent before 31 October extends your lodgment deadline to 15 May 2027. See our individual tax return service for how we manage the return process for Adelaide and regional SA clients.