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What is a TFN?

Your Tax File Number (TFN) is a unique 9-digit number issued by the Australian Tax Office (ATO), that’s used to identify you for tax and super purposes. You keep the same TFN for life, even if you change your name, job or address. If you don’t have a TFN, you can apply for one via the ATO website. 

Why do I need to provide my TFN?

While it’s not compulsory to provide your TFN or TFN exemption, if you don’t, we may be required by law to deduct Withholding Tax at the highest marginal rate plus Medicare Levy on any interest earned on your accounts. 

How to add your TFN?

You can easily add your TFN in Online Banking or the Westpac App

How to add your TFN

You can easily add your TFN in Online Banking or the Westpac App.

In the Westpac App

Before trying these instructions make sure you  update to the latest version of the app.  
  1. Search Tax File Number
  2. Select the account you wish to update
  3. Tap Choose option
  4. Tap Enter Tax File Number or Declare Tax File Number exemption
  5. Enter details and tap Update
  6. Repeat above steps for all accounts you wish to provide TFN

In Online Banking

  1. Go to Services > Preferences > Tax File Number
  2. Select Update Tax File Number
  3. Enter the SMS Code sent to your registered mobile and select Authorise
  4. Select the account you wish to update
  5. Enter your TFN or TFN exemption and select Save
  6. Repeat above steps for all accounts you wish to provide TFN

Frequently asked questions

You can find your TFN on your:

  • myGov online account
  • notice of assessment (NOA)
  • letters from the ATO
  • super statement

Download the App to add your TFN to your account

Things you should know

Read the Westpac Online Banking Terms and Conditions (PDF 236KB) at westpac.com.au before making a decision and consider whether the product is right for you.


The taxation position described is a general statement and should only be used as a guide. It does not constitute tax advice and is based on current tax laws and their interpretation.


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