Business basics · AU

ABN (Australian Business Number)

The 11-digit number that identifies your business.

An ABN is a unique 11-digit number that identifies your business to the government, other businesses and the ATO. You put it on invoices, use it to register for GST, and quote it so clients don’t have to withhold tax from your payments. It’s free to apply for and you can be a sole trader with just an ABN.

Grounded in ATO guidance. General information, not tax advice.

Related terms

Sole trader

The simplest business structure — you and the business are one.

TFN (Tax File Number)

Your personal reference number in the tax system.

GST (Goods and Services Tax)

Australia’s flat 10% tax on most goods and services.

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