Question 1

What is an ABN?

Accepted Answer

An Australian Business Number (ABN) is an 11-digit identifier issued to businesses and organisations by the Australian Business Register (ABR). It is used for tax and business dealings with the ATO and other government agencies.

Question 2

How do I validate an ABN?

Accepted Answer

ABNs use a checksum algorithm. The 11 digits are multiplied by specific weights (10, 1, 3, 5, 7, 9, 11, 13, 15, 17, 19) and summed. If the sum is divisible by 89, the ABN is valid. For full business details, search the ABR at abr.business.gov.au.

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