Do I Need to Register for GST? Australia's $75,000 Threshold [2026 Guide]

You need to register for GST in Australia once your business’s GST turnover reaches $75,000, or $150,000 if you run a non-profit, according to the Australian Taxation Office (last updated May 2025). Below that, registration is optional unless you drive a taxi, limousine, or ride-sourcing vehicle, in which case it is compulsory from your very first fare. Here is exactly how the ATO calculates your turnover, when voluntary registration below the threshold makes sense, and what happens if you cross the line and do not register in time.

How do I know if I have reached the $75,000 GST turnover threshold?

The ATO does not wait for tax time to check this. It runs two separate tests every month, and you only have to meet one of them. Your current GST turnover is your gross business income for the current month plus the previous 11 months. Your projected GST turnover is your expected income for the current month plus the next 11. Reach $75,000 on either test and you are required to register, even if the other test still comes in under the threshold.

The ATO’s own worked example makes this concrete. Barry is a sole trader who sells specialized car parts. At the end of May, his gross business income for the month is $2,560, and adding that to the previous 11 months brings his current GST turnover to $31,170, comfortably under the threshold. He still has to keep recalculating his projected turnover every month, and the moment that projection reaches $75,000, he has 21 days to register from that point, not from the end of the financial year.

Figure 1: Barry’s current GST turnover measured against the $75,000 compulsory registration threshold, using the ATO’s own worked example. Source: Australian Taxation Office, Registering for GST.

One detail catches business owners out: capital asset sales and one-off sales tied to winding down a business do not count toward projected turnover. A single large asset sale will not accidentally push you over the threshold on its own.

Do I have to register if my turnover is under $75,000?

No, not unless you fall into one of the ATO’s mandatory categories covered below. Registering below the threshold is entirely optional, and plenty of small businesses stay unregistered for years while they build up revenue. The trade-off is straightforward: registering lets you claim GST credits on the GST you pay for business purchases, which matters more once your expenses climb, but it also means charging GST on everything you sell and lodging a business activity statement (BAS) on a regular cycle.

There is one commitment worth knowing before you register voluntarily. Once you choose to register, the ATO generally requires you to stay registered for at least 12 months before you can cancel, even if your turnover never gets close to $75,000. That is a longer commitment than most people expect from a decision framed as “optional.”

Figure 2: The compulsory GST registration threshold for a standard business versus a non-profit organization. Source: Australian Taxation Office, Registering for GST.

Which businesses must register no matter their turnover?

Three categories bypass the turnover test entirely, according to the ATO. Non-profit organizations get a higher threshold, $150,000 rather than $75,000, but they are not exempt, just given more room. Taxi, limousine, and ride-sourcing drivers, an explicit category that covers Uber, Ola, DiDi, and similar platforms, must register for GST regardless of turnover, whether they own the vehicle or lease it. And any business that wants to claim fuel tax credits has to be GST-registered to do it, whatever its turnover looks like.

That ride-sourcing rule surprises a lot of new drivers, since $75,000 is a substantial year of part-time driving income for most people. The ATO treats ride-sourcing as functionally identical to running a taxi service for GST purposes, so the exemption that applies to most small side businesses under the threshold simply does not apply here.

If you are tracking your turnover month to month and want a deeper walkthrough of exactly how the ATO’s current-versus-projected calculation works, including edge cases around seasonal income and multiple revenue streams, that calculation deserves its own dedicated guide rather than a summary here.

What is the deadline once you cross the threshold?

Twenty-one days, and it is a hard deadline rather than a suggestion. Whether you hit the threshold through your current turnover, your projected turnover, or you already know you will exceed it when you start a new business, you have 21 days from that point to register, according to the ATO. Registration itself requires an Australian business number (ABN) first, and from there you can register online, by phone, or through a registered tax or BAS agent.

Figure 3: The 21-day window to register for GST once you cross the threshold, alongside the separate 28-day window to issue a tax invoice a customer requests. Source: Australian Taxation Office, Registering for GST and Tax invoices.

These two deadlines get confused often enough to be worth separating clearly. The 21-day clock is about registering for GST in the first place. The 28-day clock is a completely different rule that only applies once you are already registered: if a customer asks for a tax invoice on a sale over $82.50, you have 28 days to provide it. Missing the first deadline is a registration problem; missing the second is a documentation problem, and they carry different consequences. Once you are registered, our walkthrough of exactly what a compliant Australian tax invoice needs to include covers that second deadline in full.

What happens if I register for GST late, or want to backdate it?

Miss the 21-day window and the ATO does not simply let the missed period slide. If you were required to register and did not, you may have to pay GST on every sale made from the date you should have registered, even on sales where you never actually charged the customer GST, plus penalties and interest on top, according to the ATO. That can mean handing over roughly a tenth of months of revenue out of your own margin rather than a customer’s payment, since the GST was never collected to begin with.

There is a partial remedy. You can apply to the ATO to backdate your GST registration, which can limit the practical damage if you catch the gap yourself before an audit does. Backdating is capped at 4 years: the ATO will not backdate a registration further back than that, and you are not treated as required to be registered before that date, unless fraud or evasion is involved. Requesting a backdated registration has to be done by phone directly with the ATO rather than through the standard online registration flow.

Figure 4: Two GST registration time commitments on the same scale: the roughly 12-month minimum stay once you register voluntarily, and the 4-year (48-month) ceiling on how far back a late registration can be backdated. Source: Australian Taxation Office, Registering for GST.

Who is actually registered for GST in Australia right now?

Most Australian businesses. As of June 2025, 2,729,648 businesses were counted as registered for GST in the ABS Counts of Australian Businesses, and 97.3% of them, 2,656,469 businesses, were small businesses with fewer than 20 employees, according to ASBFEO’s calculations from that ABS data. Medium businesses (20 to 199 employees) accounted for another 67,857, and large businesses (200 or more employees) made up just 5,322.

Figure 5: Australian businesses by employment size, June 2025. Source: ABS Counts of Australian Business, Table 13, August 2025, via ASBFEO.

That population of small, GST-registered businesses is also where most of the country’s GST revenue ultimately originates. Net GST cash collections reached $90.2 billion in the 2024-25 financial year, up 6.2% from $84.9 billion the year before, according to the ATO’s GST Administration Annual Performance Report 2024-25, almost all of it tied to tax invoices those same businesses issue and record correctly. Getting registered and invoicing correctly is only half the equation; Australian invoices still settled an average of 6.9 days past their due date in the March quarter of 2026, a separate cash-flow problem that has nothing to do with whether your GST paperwork is in order. A BillyPaid invoice calculates and shows the GST amount automatically on every line, so once you are registered, the compliance side of GST does not depend on you doing the arithmetic by hand on every sale.

GST registration rules at a glance

Category	Threshold	Must register by	Notes
Standard business	$75,000 GST turnover	21 days after crossing	Current or projected turnover, checked monthly
Non-profit organization	$150,000 GST turnover	21 days after crossing	Higher threshold than a standard business
Taxi, limousine, ride-sourcing	Any turnover	From your first fare	No threshold at all, owner-driver or leased vehicle
Voluntary (below threshold)	Optional	No deadline	Generally must stay registered at least 12 months

Table 1: The four GST registration paths and their triggers. Source: Australian Taxation Office, Registering for GST.

The Bottom Line

The GST registration decision comes down to one number for most businesses: $75,000 in current or projected turnover, checked monthly rather than once a year, with $150,000 for non-profits and no threshold at all for taxi, limousine, and ride-sourcing drivers. Cross it and you have 21 days to register, or you risk owing GST on past sales plus penalties, with backdating capped at 4 years as the only partial fix. Registering below the threshold is optional, but it comes with a roughly 12-month minimum commitment once you do it, so it is worth doing deliberately rather than defaulting into it. Whichever side of the threshold you land on, an invoice that already shows the right GST treatment by default removes one more thing to get wrong.

Frequently Asked Questions

Do I need to register for GST if my turnover is under $75,000? Generally no, unless you drive a taxi, limousine, or ride-sourcing vehicle, in which case registration is compulsory regardless of turnover, according to the ATO. Below $75,000, registration is optional. You can still register voluntarily to claim GST credits on your purchases, but you generally have to stay registered for at least 12 months once you do.

How is GST turnover actually calculated? The ATO uses two tests, and you only need to meet one. Your current GST turnover is your gross business income for the current month plus the previous 11 months. Your projected GST turnover is your expected income for the current month plus the next 11. If either reaches $75,000 ($150,000 for non-profits), you must register, and you have 21 days to do it from the point the threshold is reached.

What happens if I do not register for GST on time? You may have to pay GST on every sale made from the date you were required to register, even on sales where you never charged the customer GST, plus penalties and interest, according to the ATO. You can apply to backdate a GST registration, but the ATO generally will not backdate it more than 4 years, absent fraud or evasion.

Do non-profits and rideshare drivers have different GST rules? Yes. Non-profit organizations get a higher compulsory threshold of $150,000 in GST turnover rather than $75,000. Taxi, limousine, and ride-sourcing drivers, including Uber, Ola, and DiDi drivers, must register for GST from their very first fare, regardless of how little they earn, according to the ATO.

Sources and References

1. Australian Taxation Office: Registering for GST (last updated May 2025), the $75,000 and $150,000 turnover thresholds, current versus projected turnover, the taxi and ride-sourcing exception, the 21-day registration window, backdating rules, and Barry’s worked example.
2. Australian Taxation Office: Tax invoices (last updated August 2025), the 28-day window to issue a tax invoice on request and the $82.50 threshold.
3. Australian Small Business and Family Enterprise Ombudsman: Number of small businesses in Australia, business counts by employment size from the ABS Counts of Australian Business, Table 13, August 2025.
4. Australian Taxation Office: GST Administration Annual Performance Report 2024-25, GST revenue performance, net GST cash collections of $90.2 billion in FY2024-25, up 6.2% from $84.9 billion in FY2023-24.

Note: All figures verified as of October 2026.