What is a tax file number (TFN)?
A tax file number, also known as a TFN, is a unique number given to every taxpayer by the ATO. It helps the government keep track of your tax return and other services. You will only get one TFN over the course of your entire lifetime, even if your name or residency status changes. Your TFN is a very important piece of confidential information and as such you should make sure to keep it secure.