Key takeaways
- You must register when your GST turnover is $75,000 or more, or is likely to reach it, and the ATO expects you to register within 21 days.
- GST turnover is gross business income excluding GST, not profit.
- Taxi, limousine and rideshare drivers must register from the first dollar, whatever their turnover.
- Below the threshold, registration is optional, and if you register you generally need to stay registered for at least 12 months.
When do you have to register for GST?
When to register for GST depends on your GST turnover, not your profit. You must register once your GST turnover is $75,000 or more, or when you expect it to reach that level, and you need to do so within 21 days of exceeding the threshold. Taxi, limousine and rideshare drivers are the exception, because the ATO requires them to register regardless of turnover.
This applies equally to GST for sole traders. The test looks at the enterprise, using gross income from all the businesses you run. Not-for-profit organisations have a higher threshold of $150,000.
How is GST turnover worked out?
Your GST turnover is your total business income, not your profit, less certain items the ATO excludes. These include the GST included in your sales, sales to associates that are not for payment and are not taxable, sales not connected with your enterprise, input-taxed sales and sales not connected with Australia.
You reach the threshold if either test is met. Your current GST turnover is the total for the current month and the previous 11 months. Your projected GST turnover is the total for the current month and the next 11 months. If you are not registered, the ATO's guidance is to check each month.
Illustrative example only: a new landscaper expects to invoice about $6,500 a month, excluding GST. Over 12 months that is $78,000, above $75,000, so registration is required from the start of the business. A second sole trader who expects about $5,000 a month projects $60,000, so registration is optional, though they should keep checking every month.
Do you have to register if you only had a one-off spike in income?
Not necessarily. The ATO states that even if your current GST turnover is at or above the threshold, you do not have to register if it is satisfied that your projected GST turnover will be less than the threshold. When working out projected turnover, you leave out amounts from selling a business asset, and sales you make solely because you are ceasing the enterprise or substantially and permanently reducing its size or scale.
If you rely on this, keep a record of the reasons and the figures, since it is the ATO that must be satisfied.
Are there reasons to register below $75,000?
Yes, in some cases registration is required whatever your turnover. The ATO lists these cases:
- providing taxi or limousine travel, including ride-sourcing
- earning income through the sharing economy or digital platforms, such as food delivery
- claiming fuel tax credits for your business
Should you register voluntarily?
If you do not fall into one of these categories, registering is optional. Business.gov.au notes that if you choose to register you must include GST in your prices. The ATO adds that you generally need to stay registered for at least 12 months. Registered businesses can claim GST credits on eligible business purchases and must lodge business activity statements (BAS).
The decision usually turns on who your customers are. A business selling to GST-registered clients may find registration makes little difference to them, while one selling mostly to consumers can feel the price effect directly. Model both before you decide.
What happens if you register late?
If you are required to register and do not, you may have to pay GST on sales made since the date you were required to register, even if you did not include GST in the price. You may also face penalties and interest. This is why a monthly turnover check matters.
Can you backdate a GST registration?
You can apply to backdate a GST registration, and the ATO limits backdating to 4 years. To request it you need to phone the ATO's business enquiries line. Related entities may also form a GST group, in which case the group's turnover includes the turnover of other members but not transactions between them, so check your structure before you count.
How do you register for GST?
You need an ABN first. Once you have one, you can register through Online services for business, by phoning the ATO's business enquiries line, or through your registered tax agent or BAS agent. The ATO then confirms your registration details, including the effective date, and you begin lodging BAS.
Has the Federal Budget changed the GST threshold?
At the time of writing, in October 2026, the ATO's registration page still states the $75,000 threshold. We did not identify a change to the GST registration threshold in the 2026-27 Federal Budget material we reviewed, but tax settings can change, so confirm the figure on ato.gov.au before you rely on it.
Would a free 30-minute session help?
If you are close to the threshold or unsure whether you are required to register, we can review your income and give you a clear answer. ANH Accounting is a Sydney advisory firm and a Registered Tax Agent (26258346). You are welcome to book a free 30-minute session, with no obligation.
Frequently asked questions
Do I need to register for GST if I earn under $75,000?
Not usually, because registration is optional below the threshold unless you drive a taxi or rideshare, earn through certain digital platforms or claim fuel tax credits.
Does the $75,000 include GST?
No, because GST turnover is your gross business income minus the GST included in your sales.
How long do I have to register once I exceed the threshold?
The ATO states that you need to register within 21 days of your GST turnover exceeding the threshold.
Do rideshare drivers have to register from their first fare?
Yes, the ATO treats ride-sourcing as taxi travel for GST purposes, so you must register regardless of your turnover.
Do I need an ABN before I register for GST?
Yes, the ATO sets out that once you have an ABN you can register for GST.
General information only, last reviewed October 2026. It is not personal advice. Tax law changes, so confirm your circumstances with a registered tax agent or on ato.gov.au.