Australia TFN Generator
Online generator for Tax File Number (TFN) issued by the Australian Taxation Office (ATO) for payroll and tax testing.
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About the Australian Tax File Number (TFN)
The Tax File Number (TFN) is an exclusive 9-digit tax identifier issued by the Australian Taxation Office (ATO) to individuals, businesses, and superannuation funds.
It is required for employment in Australia, filing income tax returns, opening bank accounts without maximum withholding tax, and tracking retirement pensions.
Anatomy & Structure of TFN (Tax File Number) — Australia
The Australian Tax File Number consists of 8 or 9 digits in 2 parts:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 8 | Base Tax Number | 8 digits | Unique tax identification sequence assigned by ATO | 12345678 |
| 9 | Check Digit | 1 digit | Calculated via weighted Modulo 11 with official ATO weights | 2 |
Official Algorithm (Weighted Modulo 11 — ATO)
Official validation algorithm for 9-digit Australian TFN:
S = Σ d[i] * W[i] (i=0..8); Valid if S mod 11 === 0
- 1. Multiply the 9 digits by official ATO weights: W = [1, 4, 3, 7, 5, 8, 6, 9, 10].
- 2. Sum all products into total S.
- 3. Compute remainder of S divided by 11.
- 4. The TFN is valid if and only if S mod 11 equals exactly 0.