If you run a business in Brisbane, or anywhere in Australia, one question comes up again and again: “Do I actually need to register for GST yet?” It sounds like a simple yes-or-no question, but the answer depends on your turnover, your industry, and sometimes even contracts you haven’t signed yet. Getting it wrong in either direction is costly – register too late and the ATO can chase you for GST you never charged; stay unregistered too long and you may be leaving input tax credits on the table.
This guide breaks down the real rules in plain English, so you know exactly where you stand.
The $75,000 Rule
The core threshold is straightforward: once your business’s GST turnover reaches $75,000 in any rolling 12-month period, GST registration becomes compulsory. For non-profit organisations, that threshold is higher, at $150,000.
A few things trip people up here:
- It’s turnover, not profit. GST turnover is based on gross business income before expenses, not what you take home at the end of the year.
- It’s a rolling 12 months, not a financial year. The ATO doesn’t wait for 30 June. You need to be checking your last 12 months of income on an ongoing basis, not just once a year at tax time.
- Both past and projected income count. If your current turnover is under $75,000 but you can reasonably expect to cross it in the next 12 months — say, you’ve just signed a retainer contract or landed a large recurring client — you’re required to register based on that projection, not just your historical figures.
- You get 21 days. Once you know you’ve reached, or are about to reach, the threshold, you have 21 days to lodge your GST registration with the ATO.
What Counts Toward the Threshold (and What Doesn't)
Most people assume every dollar coming into the business counts, but the calculation is more specific than that.
Included: taxable sales and GST-free sales (this includes most exports connected with Australia, even though you don’t charge GST on them).
Excluded: input-taxed supplies such as residential rent or certain financial supplies, the GST component of any sales you already charge, and – for the projected turnover test only – proceeds from selling a business asset like a vehicle or equipment.
This distinction matters a lot for businesses with a mixed income stream, for example a business that earns rental income alongside trading income. Treating everything the same way can either push you into unnecessary registration or leave you under-registered when you shouldn’t be.
Businesses That Must Register Regardless of Turnover
There are two well-known exceptions where the $75,000 threshold simply doesn’t apply, and registration is mandatory from your very first dollar of income:
- Taxi, limousine and rideshare drivers – this includes Uber, Ola and similar platforms.
- Any business claiming fuel tax credits – regardless of how small the business is otherwise.
If either applies to you, don’t wait for turnover to catch up; register from day one.
Grouped and Related Entities
If your business is part of a group of related or closely connected entities, the ATO may look at combined turnover across the group rather than assessing each entity separately. This is a common trap for business owners who run several trading entities under one umbrella, thinking each one individually sits under the threshold. If the entities are grouped for GST purposes, that logic doesn’t hold, and registration obligations are assessed on the aggregated figure.
What Changes Once You're Registered
Registering for GST is not just an administrative tick-box. It genuinely changes how your business operates:
- You must add 10% GST to your taxable sales and issue tax invoices that show it.
- You need to lodge a Business Activity Statement (BAS), usually monthly or quarterly, reporting GST collected and GST paid.
- You can claim input tax credits on GST you pay for business purchases and expenses, which can meaningfully improve cash flow if your input costs are high.
- Your pricing and contracts may need to be reviewed, especially if you’ve been quoting prices without factoring in GST.
Should You Register Voluntarily, Even Below the Threshold?
Yes, this is allowed, and for some businesses it makes financial sense even before you’re legally required to. If you have significant upfront costs — buying equipment, setting up premises, paying for stock — voluntary registration lets you claim back the GST on those purchases straight away rather than waiting until you cross the threshold. The trade-off is the added admin of lodging BAS returns and charging GST on your invoices, which can make your pricing less competitive if your customers aren’t GST-registered themselves.
This is exactly the kind of decision that benefits from a proper conversation rather than guesswork, because the right call depends on your specific cost structure, customer base and growth plans. This is where a firm like WOW! Advisors can walk through your numbers and tell you whether early registration actually helps or just adds paperwork — our GST services cover exactly this kind of registration and ongoing BAS support.
A Practical Example
Imagine a Brisbane-based consultant earning $6,000 a month, sitting at around $72,000 in trailing 12-month turnover — just under the threshold. They then sign a 12-month retainer worth $30,000. Their projected turnover for the next 12 months jumps to roughly $88,000, comfortably over $75,000. From the moment that contract is signed, they have 21 days to register for GST, even though their actual historical income hasn’t technically crossed the line yet. This is the scenario that catches out a lot of growing service businesses.
Staying on Top of It
The safest approach isn’t to check your turnover once a year – it’s to build a habit of reviewing it monthly, especially if your business is growing quickly or you’re about to sign a large new contract. Proper bookkeeping and accounting support makes this far easier to track in real time rather than reconstructing it retrospectively at tax time.
If you’re unsure whether you’ve crossed the threshold, or whether voluntary registration would benefit your business, getting proper advice early saves a lot of stress later – particularly if you’re still in the early stages of setting up your business. WOW! Advisors works with Brisbane business owners on exactly this kind of structural and compliance decision, as part of a broader approach to keeping tax obligations correct and cash flow healthy.
FAQ
Do I need to register for GST as a sole trader?
Yes, the same $75,000 threshold applies to sole traders as it does to companies, partnerships and trusts. Your GST turnover is assessed the same way regardless of your business structure.
What happens if I don't register for GST when I should have?
The ATO can require you to pay GST on sales made from the date you should have registered, even if you didn’t charge your customers GST at the time. Penalties and interest can also apply, so it’s important to register on time rather than after the fact.
Can I register for GST voluntarily if my turnover is under $75,000?
Yes, voluntary registration is available below the threshold. It can be worthwhile if you have significant GST on business expenses you’d like to claim back, but it also means you must charge GST and lodge regular BAS returns.
Does GST-free income count toward the $75,000 threshold?
Yes, GST-free sales (like most exports) still count toward your GST turnover, even though you don’t charge GST on them. Input-taxed supplies, such as residential rent, are excluded.
How often do I need to lodge a BAS once I'm registered?
Most small businesses lodge quarterly, though some lodge monthly depending on turnover and ATO requirements. Your registered tax agent can confirm your correct lodgment cycle.
I run an Uber and a small retail shop — do both need to register separately?
Rideshare driving requires GST registration from the first dollar earned, regardless of your other business turnover. Your retail shop would be assessed separately against the standard $75,000 threshold, unless the two are structured in a way that groups them for GST purposes.
What if my income fluctuates a lot month to month?
Because the threshold is based on a rolling 12-month period, seasonal or fluctuating income doesn’t exempt you — you still need to monitor your trailing 12-month turnover consistently, not just look at your best or worst months in isolation.
Can my accountant handle GST registration for me?
Yes, a registered tax agent can manage the entire registration process, assess whether you’ve crossed the threshold or should register voluntarily, and set up your BAS lodgment schedule so nothing gets missed going forward.
