You must register once your business turnover reaches the ATO’s registration turnover threshold, or as soon as you expect it to within the year — and immediately if you drive ride-share or taxi, regardless of turnover. Below the threshold it’s optional, and sometimes worth doing voluntarily. “Turnover” means gross business income, not profit, so check the current threshold against your rolling figures.
What it depends on
Where judgement stays human: Whether to register voluntarily, and when a projection genuinely crosses the line, is a judgement call — register too late and you’re exposed; too early and you add admin you didn’t need.
The test is forward-looking as well as backward: you register when your current or projected annual turnover hits the threshold, not only after it has. Waiting until your accountant notices at year-end can leave you liable for GST you never collected.
Voluntary registration below the threshold can make sense if you buy a lot of GST-inclusive inputs or sell mainly to other registered businesses — but it also means charging GST and lodging BAS, so it’s a trade-off, not a free win.
Whether to register voluntarily, and when a projection genuinely crosses the line, is a judgement call — register too late and you’re exposed; too early and you add admin you didn’t need.
Sydney Accountants · general information current as at 1 September 2026. This is general information only, not personal financial, tax or legal advice.