Australia ACN Validator
Validate Australian Company Numbers (ACN) using official ASIC Modulo 10 check digit calculation.
About Australian Company Number (ACN)
The Australian Company Number (ACN) is a unique 9-digit identifier issued by ASIC to registered companies in Australia.
It also forms the last 9 digits of an Australian corporate ABN.
Anatomy & Structure of Australia ACN
The Australian Company Number consists of 9 digits structured as follows:
| Position | Field | Length | Meaning & Rule | Example |
|---|---|---|---|---|
| 1 to 8 | Sequential Number | 8 digits | Registration sequence allocated by ASIC | 004085 |
| 9 | Check Digit | 1 digit | Calculated using ASIC Weighted Modulo 10 | 6 |
Official Checksum Algorithm (Weighted Modulo 10 — ASIC)
Official formula published by ASIC:
S = Σ (d[i] * (8 - i)) [i=0..7]; Remainder = S mod 10; Check = (10 - Remainder) mod 10.
- 1. Multiply each of the first 8 digits by descending weights from 8 down to 1.
- 2. Sum all products to calculate total S.
- 3. Compute remainder = S modulo 10.
- 4. Subtract remainder from 10; if result is 10, check digit is 0.
- 5. Result must match the 9th digit of the ACN.