Australia ABN Validator
Check an 11-digit Australian Business Number with the official mod-89 checksum. 100% local — your number is never uploaded. Built for Australia.
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Result
Batch check — paste many, one per line
Validate an Australian ABN
Enter an 11-digit ABN to verify its checksum (mod 89). Spaces are ignored. Everything runs locally in your browser.
FAQ
What is an ABN?
The Australian Business Number — an 11-digit identifier for businesses registered with the Australian Business Register.
How is it validated?
Subtract 1 from the first digit, multiply each digit by its weight (10,1,3,5,7,9,11,13,15,17,19), sum them, and check the total is divisible by 89.
Does this confirm the business is registered?
No — it only checks the number’s checksum. To confirm registration, look it up on the official ABN Lookup.
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