How to obtain the tax file number algorithm

Original Published Date
Tax Category
Tax preparation
Business accounting
Investment bodies
Resource Type
Guides and instructions

The tax file number (TFN) algorithm is a mathematical formula that tests the validity of numbers quoted as TFNs. Its use in software is recommended as it will minimise TFN errors and may subsequently reduce the need for contact between your organisation or your clients and the ATO.

To obtain a copy of the TFN algorithm you will need to:

  1. Register for a Login/Password (If you already have a Login, skip this step)
  2. Login
  3. Request access to 'Controlled Information' in the 'Tax file number (TFN) algorithm' category
  4. When the request for access has been processed you will be notified by email and the TFN algorithm will be available for you to download.

The factsheet contains information about your obligations and responsibilities for obtaining access to the TFN algorithm.

File Size Upload date
Updated TFN algorithm fact sheet - clean (PDF) 172.84 KB 15 Aug 2019
Updated TFN algorithm fact sheet - tracked (PDF) 173.7 KB 15 Aug 2019

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