Small business money basics: ABN, invoicing, GST
The three registrations that matter first, and how to keep the books honest from day one.
3 minute read · Last updated 5 October 2026
The registrations
Three things come up first. An ABN identifies your business. Registering for GST depends on your turnover and is compulsory above a threshold — below it you may still choose to register. A business bank account keeps your money separate, which makes tax and records far simpler.
The business name, the ABN and GST registration are handled through official registers, and the thresholds change, so check the current rules on the official sites.
Invoicing
A tax invoice has to carry certain details — who is selling, who is buying, what was supplied, the amount and the GST if you are registered. Missing details can mean a customer cannot claim it, and you do not get paid on time.
Invoice immediately, number every invoice, and record the date it is paid. A simple spreadsheet beats memory every time.
The habits that save you
Put a share of every payment aside for tax as it comes in, not at the end. Photograph every receipt. Reconcile monthly, not annually. And keep business and personal accounts apart from the first day, so you never have to unpick them later.
Rules, thresholds and record-keeping requirements are set by official bodies and change. Confirm the current position before relying on it.
The one thing to take away
Get the right registrations, invoice with the required details, and separate business money from personal.
Official sources
Always check the official source. Rates, fees and rules change.