Australia ABN Validator
Online corporate Australian Business Number validator. Excellent for QA.
How does ABN validation work?
ABN validation checks if the string has exactly 11 digits, subtracts 1 from the first digit, and multiplies each by the ATO weights table from 10 to 19.
If the total accumulated weighted sum is divisible by 89 (remainder of zero), the ABN is considered mathematically valid.