A sole trader generally needs GST registration when current or projected GST turnover reaches $75,000, using business income rather than profit. An exception can apply to the current-turnover test if the ATO is satisfied projected turnover will stay below the threshold. Once registration is required, you have 21 days to register.[1][2]
Two tests, both rolling
The ATO looks at your turnover over a rolling 12 months, not the financial year. You reach the threshold if either test is met.
Even if your current turnover is at or above $75,000, you do not have to register if the ATO is satisfied your projected turnover will be under the threshold. Sales of business assets and sales caused by closing or substantially shrinking the business are left out of the projection.
| Test | Months counted | You must register when |
|---|---|---|
| Current GST turnover | This month plus the previous 11 | The total is $75,000 or more, subject to the projected-turnover exception above |
| Projected GST turnover | This month plus the next 11 | The total is likely to be $75,000 or more |
Sources[1]
What counts, and when to check
GST turnover is business income across the businesses you run, with GST and the ATO's specified exclusions left out. It is not what remains after paying materials, wages and overheads.
Check monthly. Calculate current GST turnover for this month and the previous 11 months. Separately estimate projected GST turnover for this month and the next 11 months. A large upcoming job can affect the projection before payment arrives. Use the ATO's calculation rules rather than adding the two periods together.
Turnover example for a sole trader
Illustrative figures: suppose your relevant business sales, after applying the GST turnover exclusions, are $6,000 in each of the 12 months in your current test. That totals $72,000. Spending $30,000 on materials does not reduce that turnover to $42,000.
Now suppose this month plus the next 11 months is reasonably expected to total $84,000. The projected test can require registration even though the current total is $72,000. Use the ATO’s detailed turnover rules for the actual sales and timing in your business.
| Check | Illustrative total | What to do |
|---|---|---|
| Current period: this month and previous 11 | $72,000 | Below the threshold in this example; still check the projection and other registration triggers. |
| Projected period: this month and next 11 | $84,000 | At or above the threshold; check registration requirements and act within the required period. |
Registering earlier by choice
You can choose to register below the threshold. Other rules can also require registration, including when you want to claim fuel tax credits. Once registered, charge GST on taxable sales and lodge activity statements; eligible business purchases may give you GST credits.
You need an ABN before registering. The ATO lists the registration options and generally requires voluntary registration to continue for at least 12 months.
A monthly GST check you can keep with your records
Use a dated note or spreadsheet so the next review starts from the same basis.
- Record the month being checked and the sales included in each rolling period.
- Apply the ATO exclusions, then total current and projected turnover separately. Do not add the two totals together.
- Record upcoming work and the assumptions behind the projected sales.
- Register within 21 days of becoming required to register for GST; that date can be earlier than when you noticed. Record the date and confirm the effective date and invoice settings with your accountant.
Common questions
Official sources
Checked 16 October 2026. Rules can change; use these sources to check the requirements for your job.
Related guides
Job workflows for plumbers.
Put it to work on the next job
Once you are registered, Leadhand can turn a quote or finished job into a GST invoice and record the payments against it. Check your own GST settings with the ATO or your accountant.
See Leadhand quoting and job records