GST registration threshold: when a small business must register

The thresholds in one view

The ATO sets three GST registration rules. The right one depends on what the business does and who it is.

Once the threshold applies, the ATO requires registration within 21 days. Backdating registration is possible, and the ATO can backdate it to the date the business was required to register.

What “GST turnover” means

GST turnover is gross business income minus GST itself. It is a measure of what the business sells, before expenses. It is not profit, and it is not revenue from a single contract. The ATO uses two calculations side by side.

Current GST turnover

Current GST turnover is total turnover for the current month plus the previous eleven months. If that figure is $75,000 or more ($150,000 for a non-profit), registration is required unless the ATO is satisfied that projected turnover will stay below the threshold.

Projected GST turnover

Projected GST turnover is total turnover for the current month plus the next eleven months. If projected turnover is likely to reach $75,000 or more, registration is required. Projected turnover excludes sales of business capital assets and sales made solely because the business is ceasing or substantially reducing in size.

Working the number out in practice

A rolling twelve-month view is the easiest way to track it. An example with illustrative round numbers: a graphic design sole trader starts billing in July 2026. Twelve-month total to June 2027: $72,000 — still under the threshold. In July 2027 the trader signs a six-month retainer at $4,000 per month on top of existing work. Projected GST turnover for the twelve months from July 2027 jumps to about $120,000 — well over $75,000. Registration is required within 21 days of forming that reasonable expectation, not when the extra cash lands.

Taxi, limousine and ride-sourcing

The ATO applies a different rule to passenger transport. Anyone providing taxi, limousine or ride-sourcing services for passengers — including rideshare drivers using platforms such as Uber or DiDi — must register for GST regardless of turnover. Registration applies from the start of providing the service.

Voluntary registration

A business under the $75,000 threshold is allowed to register voluntarily. Voluntary registration can suit a business that mostly sells to GST-registered customers who can claim the GST back, has significant GST on expenses it wants to claim as credits, or is close to the threshold and prefers to register before it is forced to. Once registered, a business generally stays registered for at least twelve months before it can cancel.

Working out which cycle to lodge

Once registered, GST is reported through a BAS. Most small businesses lodge quarterly. A business with GST turnover of $20 million or more must lodge monthly. The due dates for each cycle are on the BAS due dates page.

Common misreadings of the rule

• Thinking the threshold is per financial year. It is a rolling twelve-month figure.
• Confusing turnover with profit. GST turnover is sales net of GST. Expenses do not reduce it.
• Waiting until the money is received. Projected turnover is based on reasonable expectation.
• Assuming the threshold applies to transport services. It does not.

Where Nella fits

Nella is an AI finance assistant for small businesses, built by the accountants at AccTek Ltd. Connected to Xero or QuickBooks, it can show rolling GST turnover from the live books and flag when the figure is approaching $75,000. Information only; the service does not register the business or lodge the BAS — a registered tax or BAS agent can do that. There is more at GST registration.

Work it out: Try the GST registration threshold checker — it runs in your browser and states the rule it applies.

Sources

• ATO u2013 Registering for GST
• ATO u2013 Working out your GST turnover
• ATO u2013 GST and taxis

Nella provides financial information and education, not accounting or tax advice. Nella shows you the numbers. When a question needs professional judgement, such as a filing or a tax decision, Nella says so and points you to a qualified accountant.