What’s a Tax File Number?

  • Your Tax File Number is for life

    Your Tax File Number (also known as a 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? You can find it on your income tax notice (notice of assessment), group certificate, super statement, or in your myGov account. 

  • Keep in mind

    When you open a CommBank account, you’re asked to provide your Tax File Number (TFN), TFN exemption, or an Australian Business Number (ABN).

    While you’re not obligated to provide your TFN, if you don’t, we are required by law to deduct tax from any interest earned on your accounts above a certain threshold (known as withholding tax). 

    You can review or update your TFN details any time using NetBank or the CommBank app. 

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

  1. Log on to the CommBank app 
  2. Go to the menu in the top left
  3. Tap Profile, then Tax File Number
  4. Choose one of the options from the drop down
  5. Tick each account you want to apply it to, then tap Submit


  1. Log on to NetBank 
  2. Go to Settings
  3. Under Profile go to Tax file number
  4. Choose an option from the drop down
  5. Tick each account you want to apply it to, then click Submit

Update your TFN now

How to add or update an ABN

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.