
Add your Tax File Number (TFN)
Manage your Tax File Number in Online Banking or the Westpac App.
What is a TFN?
Your 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
In the Westpac App
- Search Tax File Number
- Select the account you wish to update
- Tap Choose option
- Enter a TFN, provide a TFN exemption or use an existing TFN
- Enter details and tap Update
In Online Banking
- Go to Services > Preferences > Tax File Number
- Select Update Tax File Number
- If prompted, enter the SMS Code sent to your registered mobile and select Authorise
- Select the account you wish to update
- Enter a TFN, provide a TFN exemption or use an existing TFN
Try our Tax organiser

Don’t sweat the small stuff at tax time! Track, view and download your tax relevant transactions using the Tax Organiser tool in the Westpac App.
Frequently asked questions
You can find your TFN on your:
- myGov online account
- notice of assessment (NOA)
- letters from the ATO
- super statement
Joint accounts may be subject to withholding tax unless at least two joint account holders provide their TFN.
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 your TFN or TFN exemption, but 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.
Things you should know
Read the Westpac Online Banking Terms and Conditions (PDF 408KB) at westpac.com.au before making a decision and consider whether the product is right for you.
Taxation considerations contained on this page should not be interpreted or used as tax advice or tax guide. You should seek independent, professional tax advice to determine the appropriate tax consequences relevant to your circumstances before making any decision based on this information.
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