Tax File Number (TFN)
A unique 9-digit number issued by the ATO to identify individuals and organisations for tax purposes.
A Tax File Number (TFN) is a unique 9-digit identifier issued by the ATO to individuals, companies, partnerships, trusts, and other entities. It is used to track your tax obligations and entitlements throughout your life. You are not legally required to have a TFN, but without one your employer must withhold tax at the highest marginal rate (45% plus Medicare levy) from your wages.
You should quote your TFN to your employer (via a TFN declaration form), your bank or financial institution (to avoid withholding tax on interest), your super fund, and Centrelink. Never share your TFN publicly or with unauthorised parties — it is a sensitive identifier similar to a Social Security Number in other countries.
Australian residents can apply for a TFN online through myGov or at a participating Australia Post office. Foreign passport holders in Australia on a valid visa can also apply. Your TFN remains the same for life, even if you change your name or address.