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Why is a tax file number important and how do you get one?

Jodie Humphries avatar
Jodie Humphries
- 3 min read
Why is a tax file number important and how do you get one?

A tax file number (TFN) is your personal, unique reference number for the Australian taxation and superannuation systems. This nine-digit number stays with you for life, even if you change your name, your job, shift to another state or even move abroad.  

Although having a tax file number is not mandatory by law, you will face some inconveniences if you don’t have one and will also have to pay more tax. You cannot apply for government benefits or file your taxes electronically if you don't have a TFN. If you have a business and need an Australian business number (ABN), you’ll need to first get a tax file number. 

Australian Taxation Office (ATO) rules state that, if you don’t provide your TFN to your employer, the employer must withhold 47 per cent of your payment for tax. If you’re wondering how to find your tax file number, it’s mentioned on your income tax notice of assessment, your superannuation account statement or your income statement from your employer. If you have an authorised tax agent, you can ask them for your TFN. You can also call 13 28 61 for help with finding your TFN. 

If you’re trying to track a super account that you’ve misplaced, your TFN number is critically important to helping you find it. You’ll need to log in to your myGov account linked to the ATO and click on ‘manage my super’. You can also conduct a super search by phoning the helpline on 13 28 65. Provide your TFN along with the other details requested in order to trace your lost super.


This article is over two years old, last updated on June 2, 2022. While RateCity makes best efforts to update every important article regularly, the information in this piece may not be as relevant as it once was. Alternatively, please consider checking recent superannuation articles.

How can I apply for a tax file number?

If you’re an Australian citizen with an Australian passport, you can apply for your TFN online at myGovID. You need to be at least 15 years old to apply here and have an Australian passport, even one that’s expired up to three years ago. You’ll also need one other Australian identity document, such as your driver’s license.

If you’re an Australian resident for tax purposes, but you don’t have an Australian passport, then you can apply for your TFN at a participating Australia Post retail outlet. You will need to complete an online application form and print it, then book your interview at an Australia Post outlet within 30 days of filling in the form. When your interview is scheduled, take the print-out of your application summary and proof of identity documents with you. Your TFN application process will be completed when you sign your application at the Australia Post outlet.  

Services Australia customers can also apply in-person at Services Australia centres if they are unable to apply online or at an Australia Post outlet. 

You do not need to pay to apply for a tax file number.

How long does it take to get a TFN number?

You can get your tax file number immediately after completing the application process on myGovID. If you apply at an Australia Post retail outlet, you should receive your TFP within 28 days.


Keeping your TFN secure

It’s very important to keep your TFN secure because you could become the victim of identity fraud if unscrupulous people gather details about you such as your name, date of birth, address, and TFN.

You should share your TFN only with people who are authorised to collect this information, such as the Australian Tax Office, Centrelink, your bank or financial institution, employer, super fund and registered tax agent.


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This article was reviewed by Personal Finance Editor Alex Ritchie before it was published as part of RateCity's Fact Check process.