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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 the Westpac Mobile App or Online Banking

How to add your TFN?

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

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

Frequently asked questions

Joint accounts may be subject to withholding tax unless at least two joint account holders provide their Tax File Number.

Visit the ATO website for further information and eligibility criteria. 

Withholding Tax is an amount that is withheld from interest earned on your account(s) if you haven’t provided your TFN or TFN Exemption. It may also apply if you have an overseas residential address.

You’re not required by law to provide us your TFN or TFN exemption, however if you don’t, we’re obligated to withhold tax at the highest marginal tax rate plus Medicare Levy.

To view any tax withheld on your accounts, download the interest and tax summary in Online Banking or the Westpac App . 

Download the App to add your TFN to your account

Things you should know


Apple and the Apple logo are trademarks of Apple Inc., registered in the U.S. and other countries. App Store is a service mark of Apple Inc.

Google Play is a trademark of Google LLC. Read the Westpac Online Banking Terms and Conditions (PDF 341KB), at 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.

© Westpac Banking Corporation ABN 33 007 457 141 AFSL and Australian credit licence 233714.