An Australian Business Number (ABN) is an 11-digit identifier used to register a business or organization with the Australian Tax Office. Businesses are legally required to obtain an ABN if they expect to generate over $75,000 in annual revenue. Having an ABN makes it easier for businesses to operate, as they can register for GST, claim tax credits, avoid PAYG tax on payments, obtain business discounts from suppliers, hire employees, and more. A key advantage is that other businesses won’t have to withhold 47% tax when paying an ABN-registered entity over $75. Overall, an ABN simplifies business operations and saves money, so it’s an essential registration for any Australian enterprise.