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.
Related Terms
ATO (Australian Taxation Office)
The government agency responsible for administering Australia's tax and superannuation systems.
Australian Business Number (ABN)
A unique 11-digit number identifying a business entity to government and the community.
Tax Return
An annual form lodged with the ATO reporting your income, deductions, and tax payable or refundable for the financial year.
PAYG Withholding
The system where employers withhold income tax from employees' wages and remit it to the ATO throughout the year.