Keep in mind

  • When you open a CommBank account, you’re asked to provide your Tax File Number (TFN) or TFN exemption
  • You’re not obligated to provide your TFN, but if you don’t, we are required to deduct tax from any interest earned on your accounts above a certain threshold (known as withholding tax)

What’s a Tax File Number?

Your TFN is a 9-digit number, issued by the Australian Taxation Office (ATO), that’s unique to you. It’s an important part of your tax and super records so keep your TFN secure.

You keep the same TFN for life - even if you change your name, address or job.

If you don’t have a TFN, you can apply for one online.

Can’t find your TFN? It will be on your income tax notice (notice of assessment), group certificate or super statement, or in your myGov account.

Why are you asked to provide your TFN?

Any interest earned on your bank accounts is part of your assessable income, and needs to be reported to the Australian Tax Office (ATO).

If you don’t provide your TFN or exemption, we’re required to deduct Withholding Tax at the highest tax rate plus Medicare Levy on all accounts that don’t have a TFN or TFN exemption .

Some people (or organisations) can claim TFN exemptions e.g. certain pensioners, most under 16s and certain non-profit organisations. Check with the ATO to see if you’re eligible.

If you have any joint accounts, each account holder must provide their TFN option individually. 

How to see, add or update your TFN or exemption

You can check if you’ve provided your TFN or add or update for each of your eligible accounts in either NetBank or the CommBank app. 

CommBank app

  • Log on to the CommBank app >
  • Choose My details from the menu in the top left > tap Tax File Number
  • Choose one of the Tax File Number options from the drop down
  • Tick each account you want to apply it to > click Submit


  • Log on to NetBank > Settings > Profile
  • Choose Tax file number
  • Choose one of the Tax File Number options from the drop down
  • Tick each account you want to apply it to > click Submit

Update your TFN now

Things you should know

The CommBank app is free to download however your mobile network provider charges you for accessing data on your phone. Find out about the minimum operating system requirements on the CommBank app page. Terms and conditions are available on the app. NetBank access with NetCode SMS is required. Full terms and conditions available on the CommBank app.