Guide to Tax File Numbers


A tax file number (TFN) is a unique nine-digit number we issue to individuals and organisations to help us administer tax and other Australian Government systems.

We only issue one TFN to you during your lifetime, even if you change your circumstances.


Attention icon If you change your name or address, you should tell us so we can update your details.

How to find your TFN

If you already have a TFN but you don’t know where it is, you may have documents that contain it, such as a notice of assessment or a payment summary from your employer. Alternatively, if you use a registered tax agent, they can tell you your TFN.

Applying for a TFN

If you’ve never been issued with a TFN, you can apply for one. You’ll receive your TFN no more than 28¬†days after we receive your completed application.

Using your TFN and keeping it safe

There are a number of situations where you will be asked to provide your TFN, such as when you start work or change jobs, apply for income assistance or join a superannuation fund. You should keep it secure and only disclose it to certain individuals or organisations for tax-related purposes.

Secondary schools TFN program

Most secondary school students are able to get a TFN through the secondary schools TFN program. This is an easier way to apply because you don’t have to provide us with any documents to prove your identity – the school identifies you.


Direction icon If you operate a partnership, trust or company and want to know how to apply for a TFN, refer to Tax basics for small business or visit the Australian business register website at to apply for an Australian business number (ABN) and TFN.