A Tax File Number (TFN) is a unique nine-digit identifier issued by the Australian Taxation Office (ATO) to individuals and organisations for tax and superannuation purposes.

It’s used to track an individual’s tax affairs, superannuation contributions, and government benefits throughout their lifetime. While not strictly mandatory, providing your TFN to employers, financial institutions, and superannuation funds helps avoid higher tax withholding rates and enables access to government benefits. TFNs are confidential and protected by strict privacy laws that regulate how they can be collected, used, and stored.

Purpose and function of Tax File Number (TFN)

Primary uses

The Tax File Number serves several essential functions in Australia’s taxation and benefits systems:

• Identifies individuals in Australia’s tax system
• Links individuals to their tax records and tax returns
• Facilitates correct PAYG withholding from salary, wages, and investments
• Enables tracking of superannuation contributions and accounts
• Allows access to government payments and services
• Helps prevent tax evasion and identity fraud
• Provides a unique identifier for ATO communications

Legal basis

The TFN system operates under specific legislation:

• Established under the Income Tax Assessment Act 1936
• Privacy protections under the Privacy Act 1988
• TFN Rule 2015 issued by the Privacy Commissioner
• Taxation Administration Act 1953 includes penalties for misuse

Obtaining a TFN

Eligibility

Those eligible to apply for a TFN include:

• Australian residents (for tax purposes)
• Foreign residents earning taxable income in Australia
• Organisations operating in Australia
• Migrants with work rights
• Temporary residents with valid visas allowing work
• Applicants for certain government benefits

Application methods

Several options are available for applying:

• Online application: Most common method for Australian residents
• Paper forms: Available from ATO offices or Australia Post
• Tax agents: Can apply on behalf of clients
• At school: Secondary students can apply through their school (group application)
• Joint applications: with visa applications for migrants
• Through Centrelink: As part of government benefit applications

Documentation requirements

Applicants must verify their identity with:

• Primary identification documents (passport, birth certificate, citizenship certificate)
• Secondary identification documents (driver’s licence, Medicare card)
• Proof of Australian residence or valid visa
• Name change documentation (if applicable)
• Original documents or certified copies required
• Different requirements for Australian citizens vs. foreign residents

Processing times

Typical timeframes for receiving a TFN:

• Online applications: 28 days
• Paper applications: Up to 28 days after receipt
• School program applications: Before the end of the school year
• Foreign resident applications: Up to 28 days
• Temporary visa holder applications: Often linked to visa processing

When to provide your TFN

Employment

Providing your TFN to employers:

• Given upon starting new employment
• Provided through a TFN declaration form
• Typically required within 28 days of starting work
• Prevents taxation at the highest marginal rate
• Used by employers for PAYG withholding calculations
• Remains valid for the duration of employment

Financial institutions

Banks and financial institutions request TFNs for:

• Interest-bearing accounts
• Term deposits
• Investment accounts
• Share dividend payments
• Unit trust distributions
• Managed fund investments
• Prevents withholding tax of 47% on investment income

Superannuation funds

Providing TFNs to super funds enables:

• Acceptance of personal contributions
• Location and consolidation of lost super
• Processing of government co-contributions
• Applying for early release if eligible
• Reduced tax on contributions (from 47% to 15%)
• More efficient administration of accounts

Government agencies

TFNs are used by various government departments:

• Australian Taxation Office (primary administrator)
• Services Australia (Centrelink, Medicare)
• Child Support Agency
• Higher Education Loan Program (HELP)
• Veterans’ Affairs
• State revenue offices (in limited circumstances)

Business registration

Additional TFN requirements for businesses:

• Companies, partnerships, and trusts require their own TFNs
• Self-employed individuals use their personal TFN
• May be required to obtain an Australian Business Number (ABN)
• Different application processes for business TFNs
• Connected to business activity statement lodgements

Privacy and security

Legal protections

TFNs enjoy significant privacy protection:

• Cannot be used as identification for general purposes
• Unauthorised use or disclosure is prohibited
• Penalties apply for misuse (up to 2 years imprisonment)
• Must not be used as a general identifier
• Cannot be required for services unrelated to tax or specific government benefits
• Cannot appear on publicly accessible documents

Authorised recipients

Only specific entities can legally request your TFN:

• Australian Taxation Office
• Employers (for PAYG purposes only)
• Financial institutions (for tax reporting only)
• Superannuation funds
• Services Australia (Centrelink)
• Registered tax agents
• Higher education providers (for HELP loans)

Storage requirements

Organisations that collect TFNs must:

• Have secure storage systems
• Restrict access to authorised personnel
• Implement data breach response plans
• Not keep TFNs after they’re no longer needed
• Follow destruction protocols for TFN records
• Comply with Australian Privacy Principles

TFN security measures

Protecting your TFN from misuse:

• Only provide it to authorised recipients
• Verify the identity of anyone requesting it
• Securely dispose of documents containing your TFN
• Never print it on business cards or display publicly
• Do not send via unsecured email
• Report suspected misuse to the ATO
• Monitor tax records for unexpected activity

Implications of not providing a TFN

Employment impact

Consequences in employment contexts:

• Withholding at the highest marginal tax rate plus Medicare levy (47%)
• No recognition of tax-free threshold
• Potential difficulty claiming overpaid tax until tax return lodgement
• Employers legally required to withhold at higher rate
• May cause cash flow issues for employees

Investment impact

Effects on investment income:

• 47% withholding tax on interest and investment income
• Dividend payments subject to highest non-declaration rate
• Managed fund distributions heavily taxed
• Can claim credit for withheld amounts when lodging tax return
• May lead to substantial tax refunds but delayed access to funds

Superannuation impact

Consequences for super accounts:

• Fund cannot accept personal contributions
• Additional 32% tax on employer contributions (total 47%)
• Government co-contribution payments not possible
• Difficulty consolidating multiple accounts
• Potential loss of super benefits
• Administrative complications for fund members

Government benefits impact

Effects on government payments:

• Delays in processing benefit applications
• May prevent access to certain payments
• Income reporting complications
• Family Tax Benefit calculation issues
• Higher education loan application difficulties
• Potential interruption of payment streams

Special situations

Lost or forgotten Tax File Number

Steps to recover a forgotten TFN:

• Check previous tax returns or payment summaries
• Look for ATO correspondence
• Check super statements or investment documentation
• Contact the ATO via phone, online services, or registered tax agent
• Verify identity before TFN disclosure
• Request in writing in certain circumstances

TFNs for children

Special provisions for minors:

• No minimum age requirement for TFN applications
• Parental consent required for children under 16
• Recommended for minors with income over the tax-free threshold
• Required for minors with investment income
• School program applications available for secondary students
• Different identity verification requirements

Foreign residents

TFN arrangements for non-residents:

• Available to those earning taxable Australian income
• Application process may require different documentation
• Not eligible for tax-free threshold unless Australian resident for tax purposes
• Required to access lower withholding rates
• Special provisions for working holiday makers
• Different tax rates apply to foreign residents

Deceased persons

Handling TFNs after death:

• TFN remains valid for finalising tax affairs
• Legal personal representative can access information
• Final tax return required (prepared by executor/administrator)
• Special labels on tax return indicating deceased status
• ATO notification process for deceased persons
• Tax implications for deceased estates

TFN and other identifiers

TFN vs. Australian Business Number (ABN)

Key differences between these identifiers:

• TFN is primarily for individuals, ABN for businesses
• ABNs are publicly available, TFNs are strictly confidential
• ABNs appear on invoices and business documents
• Different application processes and requirements
• Some entities need both (e.g., sole traders, partnerships)
• Different uses in the tax system

TFN vs. Medicare number

Distinctions between health and tax identifiers:

• Different government departments (ATO vs. Services Australia)
• Different purposes (tax vs. healthcare)
• Different privacy and security requirements
• Separate application processes
• Cannot be used interchangeably
• Both may be required for certain government services

International equivalents

Similar systems in other countries:

• United States: Social Security Number (SSN)
• United Kingdom: National Insurance Number
• Canada: Social Insurance Number (SIN)
• New Zealand: Inland Revenue Department (IRD) Number
• No direct international recognition of TFNs
• No automatic conversion when migrating to Australia