Your TFN and keeping it safe

A TFN is a unique number we issue to individuals. It is an important part of your tax and superannuation records, and your identity. It is also an important part of locating and keeping track of your superannuation savings.

In the wrong hands, your TFN could be used to commit fraud, so keep it safe. Make sure you protect your identity by keeping all your personal details secure, including your TFN.

We only issue one TFN to you during your lifetime, even if you change jobs, change your name, or move.

See also:

  • To find out more about how to protect your TFN and avoid identity crime, refer to Identity crime.

When to use this form

You can use this form if you:

  • have never had a TFN
  • are not sure if you have a TFN
  • have a TFN, but cannot find it on any of your tax papers.

What if you have lost your TFN?

If you have lost your TFN or are not sure you have one, check all your correspondence from us, or contact your registered tax agent.

If you still cannot find your TFN, or would like to update your details, you can contact us – see More information.

Who should sign your application?

If you are:

  • 12 years old or under – your parent or guardian must sign on your behalf
  • 13 to 15 years old – you or your parent or guardian can sign
  • 16 years or older – you must sign your application.

If you are unable to sign your own application because of a disability and you are:

  • 15 years old or under – your parent or guardian can sign on your behalf
  • 16 or 17 years old – your parent or guardian can sign, but they must provide a signed statement from a doctor explaining your circumstances
  • 18 years or older – a court-appointed guardian can sign, but they must provide legal proof of guardianship, such as a power of attorney or a court order.

If a parent or guardian signs on behalf of the applicant, they will need to provide additional information when they submit the form – see Parent or guardian.

If you complete a TFN application on behalf of another person, this does not give you the authority to ask about their tax matters.

Last modified: 05 Nov 2015QC 27134