The business is getting busier. A few larger jobs have landed, referrals are coming in and the invoice total is starting to look healthy. This is the moment to check GST, before your next quote turns into a pricing surprise.
GST registration is not something to leave until your accountant prepares the annual return. Nor is it determined by the profit left after paying expenses. It is a turnover question with a forward-looking component.
The threshold is not your take-home pay
As at 8 September 2026, the general GST registration threshold for a business is $75,000. Different rules apply to not-for-profit organisations, and some activities, including taxi and ride-sourcing services, can require registration regardless of turnover. Check the ATO’s registration guidance before applying the general threshold to your situation.
You assess GST turnover using the relevant current and projected periods. Current turnover looks at the current month and the previous 11 months. Projected turnover looks at the current month and the next 11 months. This is not simply a running total that resets to zero on 1 July.
Where current turnover reaches the threshold, the projected-turnover exception may matter. Equally, a forecast that meets the threshold can require action before your historical sales get there. This is why “I have not earned $75,000 yet” does not always settle the question.
Work out which sales belong in the calculation
GST turnover is a defined measure. It is not every deposit in the business bank account, and it is not the accounting profit. Owner contributions and loan proceeds are not ordinary sales revenue. Other exclusions and special rules also need consideration.
Do not assume that sales without GST are all ignored. GST-free sales and input-taxed sales are different categories. If your business makes exempt-looking supplies, overseas sales or property transactions, ask for the turnover calculation to be reviewed rather than relying on the tax code currently used in your software.
There is also a distinction for capital assets: proceeds from disposing of a capital asset are excluded from projected GST turnover. The ATO explains this in its capital asset disposal guidance. That does not mean a registered business can assume the sale itself has no GST consequences.
A forecast should explain the business, not guess at it
Illustrative example: A service business has generated $54,000 over its current look-back period. It then signs recurring work expected to produce approximately $7,000 a month. The owner should review projected turnover now. Waiting until cumulative receipts pass $75,000 may put registration behind the point at which it was required.
Keep the evidence behind the forecast: signed agreements, expected commencement dates, realistic utilisation and known contract endings. Separate confirmed work from hopeful enquiries. A short note explaining the assumptions is more useful than an unexplained number in a spreadsheet.
Build a monthly GST check into your bookkeeping routine while turnover is close to the threshold. The government’s GST registration guide explains the 21-day registration requirement when the obligation arises. The point is to identify that obligation promptly, rather than discover it several quarters later.
Review the price customers have agreed to pay
Registration affects how you invoice taxable sales and account for GST. It does not necessarily give you a contractual right to add 10% to a price a customer has already accepted.
Read your quote terms and ask whether prices are GST-inclusive or whether GST is added where applicable. For consumer-facing offers, ensure the displayed total is appropriate. Get advice on a difficult existing contract before sending a revised invoice that assumes the customer must absorb the change.
Update invoice templates, accounting settings and the relevant tax codes from the correct effective date. Put money aside for the expected net GST liability. The bank balance can feel generous when it contains amounts that will later be paid through the BAS.
Voluntary registration is a business decision too
If you are below the threshold, voluntary registration may be available. Consider who your customers are, the GST treatment of your sales, eligible credits on purchases and the administration involved. Registration brings ongoing obligations, even during a quiet period.
Once registered, GST credits are subject to their own conditions and evidence requirements. The ATO’s credit guidance is useful when setting up your purchase records.
For a practical review, bring your last 12 months of sales, the next year’s expected work and examples of your quotes. That lets the discussion cover the effective date, customer pricing and cash flow together. Growth is welcome. An avoidable GST bill is a less enjoyable way to discover it.
Target Advisory 