You must register for GST in Australia if your GST turnover is $75,000 or more ($150,000 or more for not-for-profit organisations), or if you provide taxi travel or ride-sourcing — in which case you must register regardless of turnover. Work out your position with the two turnover tests above, then register within 21 days if you are required to.
Once registered, use the GST Calculator and the Reverse GST Calculator to handle GST on your prices, or browse the full calculator suite.
The two turnover tests
GST registration turns on your GST turnover, which is measured two ways. You reach the threshold if either test does:
- Current GST turnover — your turnover for the current month plus the previous 11 months.
- Projected GST turnover — your turnover for the current month plus the next 11 months.
The projected test is the one that usually decides it. If your projected turnover is at or above the threshold, you must register. If only your current (backward-looking) turnover has reached the threshold but you can reasonably show your turnover will stay below it going forward, you are generally not required to register — though you should be able to substantiate that.
Worked example
A sole trader turned over $60,000 in the last 12 months (current) and expects $80,000 over the next 12 months (projected). Because the projected figure is at or above $75,000, they must register for GST — within 21 days of realising it.
The 21-day rule
Once you become required to register, you have 21 days to do so. Registering late can mean you still owe GST on sales made from the date you were required to register, even if you did not charge it — so the GST comes out of your own pocket.
Taxi and ride-sourcing: register from the first dollar
If you provide taxi travel — including ride-sourcing through platforms such as Uber and DiDi — you must be registered for GST regardless of your turnover. The $75,000 threshold does not apply to you; the obligation starts from your first fare.
Not-for-profit organisations
Not-for-profit organisations have a higher registration threshold of $150,000. Below that, registration is optional; at or above it, the same current and projected tests apply.
What counts as GST turnover
GST turnover is your gross business income excluding GST — not your profit. It excludes:
- GST you have included in prices,
- input-taxed sales (such as residential rent and most financial supplies),
- sales not connected with Australia, and
- sales that are not for payment.
Common mistakes
- Only checking last year’s figures. The projected (forward) test matters just as much as the current (backward) test.
- Confusing turnover with profit. The threshold is measured on gross income, before expenses.
- Assuming rideshare has a threshold. Taxi and ride-sourcing drivers must register from the first dollar.
- Registering late. The 21-day clock starts when you become required, not when it is convenient.
Frequently asked questions
What is the GST registration threshold in Australia?
$75,000 of GST turnover for businesses, and $150,000 for not-for-profit organisations. Taxi and ride-sourcing drivers must register regardless of turnover.
Do I have to register if I go over $75,000 once?
You must register if either your current or projected GST turnover reaches $75,000. If a one-off spike pushed your past-12-month figure over but your forward-looking turnover is clearly below, you may not be required to register — but keep evidence.
How long do I have to register for GST?
21 days from when you become required to register.
Can I register for GST voluntarily?
Yes. If your turnover is under the threshold you can still register — useful if you want to claim GST credits on purchases — but you will then have to charge GST and lodge activity statements.