Side Hustle Tax in Australia: GST, Income Tax and Super

Revenue is a seductive number. It is also the wrong number to move into your spending account. The tool below separates customer receipts into running costs, GST, the extra personal assessment created by the business, an optional personal super contribution and genuinely available cash.

Use rolling 12-month turnover rather than the financial-year total in your bookkeeping dashboard. Enter ordinary running costs here; equipment depreciation, private-use adjustments, non-commercial losses and personal services income need a proper tax return calculation.

“Side hustle” describes when you do the work, not its legal or tax character. An online store, weekend photography, consulting, content channel or repair service can be a business while the owner remains a full-time employee. Conversely, occasionally selling a handmade item for the cost of materials can remain a hobby.

There is no revenue threshold that flips one into the other. The ATO looks at the activity as a whole. Indicators pointing toward a business include:

• an intention to make a profit, even if the first months are loss-making;
• repeated, regular and commercially sized activity rather than an isolated sale;
• a plan, pricing method, marketing, customer acquisition and records that resemble other operators in the industry; and
• taking concrete steps to start: acquiring the minimum assets, opening for orders or beginning the service, rather than merely researching an idea.

Registration is evidence of a businesslike approach, but an ABN does not create a business by itself. Nor does calling an activity a hobby settle the question. A separate profit-making transaction may still have tax consequences even when the broader activity is not a business.

Do you need an ABN?

A sole trader uses their existing individual TFN for the tax return; an ABN is a separate public identifier for business dealings. Eligible businesses can register free through the Australian Business Register. An ABN lets you register for GST, identify the business on invoices and avoid the no-ABN withholding rule. If you supply another business without quoting an ABN, that payer may need to withhold 47% from payments unless an exception applies.

An ABN and GST registration are different decisions. There is no $75,000 ABN threshold; the number belongs to GST. You may need an ABN long before GST becomes compulsory. If you trade under a name other than your own personal name, business-name registration is another, separate step.

For an ordinary for-profit enterprise, GST registration becomes compulsory when GST turnover is $75,000 or more. That is gross business income from all enterprises operated by the same entity, excluding GST itself and specific excluded sales. It is not profit, taxable income, money left after platform fees, or a July-to-June total.

The two rolling tests are:

• Current GST turnover: sales for the current month and the previous 11 months.
• Projected GST turnover: sales for the current month and the next 11 months that are likely on reasonable evidence.

Check both every month. A steady $6,250 a month is a $75,000 annual pace, but lumpy businesses must use the actual rolling windows. If projected turnover is likely to reach the threshold, the ATO says registration is required within 21 days. If current turnover is already over the threshold but projected turnover is genuinely below it, ATO guidance provides an exception; evidence of a permanent scale reduction or cessation matters.

What belongs in GST turnover?

Taxable sales and GST-free sales generally count. Input-taxed sales, sales not connected with the enterprise or Australia, and GST already included in prices do not. When calculating projected turnover, also leave out sales of capital assets and sales caused solely by closing or substantially and permanently shrinking the enterprise. If one ABN operates several small ventures, their turnover is not tested in separate $75,000buckets.

Registration does not mean the ATO takes 10% of profit. It means taxable sales carry GST, eligible business purchases can generate GST credits, and the net amount is reported on a business activity statement. Whether the commercial cost falls on the customer or the business depends on pricing.

Add GST on top

A service previously priced at $100 becomes $110. The business keeps$100 of sales revenue and holds $10 as output GST before credits. This preserves the pre-GST margin but raises the customer-facing price. It is often easier with GST-registered business clients, who may claim a credit, than with consumers who cannot.

Absorb GST inside the existing price

If the customer still pays $100, revenue is only $91 and $9 is GST. The correct fraction is one-eleventh of a GST-inclusive price, not 10%. On $80,000 of unchanged customer receipts, that redirects about $7,273 from revenue to output GST before credits. Registration can therefore create a sharp margin squeeze even though customer sales have not moved.

GST credits are not a refund for every expense

A registered business can generally claim the GST in purchases used to make taxable or GST-free sales, to the extent they are for business use. There is no credit where the supplier did not charge GST, for wages, private use, or purchases connected to input-taxed sales. A valid tax invoice is generally needed for purchases above $83 including GST. The income-tax deduction is then normally based on the cost after the GST credit, so the same GST is not claimed twice.

A sole trader does not lodge a separate company tax return. Business income and expenses go into the business section of the individual return; the resulting net profit joins salary, interest and other assessable income. The label on the bank account does not change this.

Suppose a worker earns $80,000 and the side business has $50,000 of sales with $10,000 of deductible costs. The taxable business amount is broadly$40,000, not $50,000. It sits on top of the salary already filling the lower tax brackets. That is why multiplying side revenue by a flat 30% can be wrong in both directions.

• Income tax is progressive. For 2026–27, resident rates are nil to $18,200, then 15%, 30%, 37% and 45% across the legislated brackets.
• The Medicare levy is generally 2%, with low-income rules that can change the effective marginal rate.
• HELP repayments use combined repayment income. Business profit can start or increase a compulsory repayment even though salary payroll cannot see it.
• The Medicare Levy Surcharge can apply without appropriate hospital cover. For a single person in 2026–27, the first threshold is $105,000of income for surcharge purposes.

The $1,000 offset many estimates omit

The unincorporated small-business income tax offset is 16% of the basic income-tax liability attributable to eligible net small-business income, capped at $1,000 a person each year. The ATO calculates it from the return. It is not 16% of profit, not a deduction and not refundable. Eligibility generally requires a sole trader or a share of small-business income from a partnership or trust with aggregated turnover below $5,000,000.

Personal services income is not included unless it comes from a personal services business. The calculator therefore lets you switch the offset off. Its estimate also does not apply non-commercial loss rules: a loss from a small side activity may have to be deferred rather than immediately reducing salary income.

Why the first tax bill is often the worst surprise

Customers do not usually withhold personal tax from a sole trader's invoices. Salary withholding continues as though the business profit does not exist. The shortfall appears on assessment. After a return shows enough business or investment income and tax payable, the ATO may enter the person into quarterly PAYG instalments; voluntary entry is also available. Instalments prepay income tax, but they are separate from GST collected on sales.

Keep records supporting income and deductions, generally for five years. A cost needs a business connection, and mixed private/business use must be apportioned. Equipment and other capital items may be depreciated or dealt with under a concession rather than deducted as a simple running cost. Cash drawings by the owner are neither wages nor a business deduction.

A self-employed sole trader or partner does not have to make Super Guarantee contributions for themselves. That is a legal answer, not necessarily an economic one. If the same work were employment, 12% of ordinary time earnings would generally be going to super in 2026–27. A side-business owner who spends every dollar of profit quietly opens a gap between current cash flow and retirement saving.

The calculator uses 12% of positive business profit as an editable benchmark. It is not an amount the ATO says a sole trader owes, and business profit is not the same legal base as employee ordinary time earnings. It simply makes the missing contribution visible.

Claiming a deduction for a personal contribution

An eligible personal contribution can be claimed as a tax deduction, making it concessional. The fund generally deducts 15% contributions tax. To claim it, the member must give the fund a valid notice of intent and receive the fund's acknowledgment before claiming in the return, within the applicable time limits.

• Employer SG from the main job, salary sacrifice and deductible personal contributions all share the $32,500 base concessional cap for 2026–27.
• Eligible people with a total super balance below $500,000 at the previous 30 June may have unused cap amounts from the previous five years, but the article calculator does not assume them.
• Division 293 can add another 15% on some concessional contributions when the legislated income-and-contributions test exceeds $250,000.
• The contribution is reportable. It reduces taxable income, but is added back for HELP repayment income and the MLS threshold test. It therefore does not normally make those obligations disappear.

The interactive projection shows the difference if the same dollar contribution were made every year to age 67. It holds today's policy and the contribution constant and uses explicit return and fee assumptions, so it is a scenario—not a prediction. The useful comparison is not the headline retirement number by itself, but the current cash cost, cap room and loss of access to money placed inside super.

The table changes both employment salary and side-business turnover while holding the operating assumptions constant. It demonstrates two relationships prose usually hides: the $75,000 GST line follows turnover, while the income-tax reserve follows profit placed on top of the existing salary.

At $80,000 and $120,000 of side turnover, GST is shown as registered and added on top of current prices. It does not appear in the “cash after tax” column because output GST and eligible input credits have already been separated before profit is calculated. If GST instead has to be absorbed inside fixed consumer prices, use the interactive tool: both profit and cash left will fall.

The cleanest system makes money unavailable before it can be mistaken for profit. The percentages will differ by business, but the accounts and review rhythm can be simple.

• Decide and document the status. Record why the activity is a hobby or a business and reassess when its repetition, profit intention or scale changes.
• Get the registrations that match the facts. Apply for an ABN if entitled, register a trading name where needed, and do not wait for the annual return to test GST.
• Track two rolling turnover numbers monthly. Save the current and projected 12-month calculations, including the assumptions behind the forecast.
• Separate GST at receipt. Once registered, move the modelled output GST into a GST clearing account, then reduce the BAS payment only for substantiated credits.
• Reserve tax from profit, not revenue. Reforecast after large expenses, a salary change, a HELP threshold crossing or loss of hospital cover. PAYG instalments already paid reduce the eventual assessment; they are not another cost.
• Make super an explicit choice. Check employer SG and other contributions already received, cap room and the notice-of-intent process before moving cash.
• Keep usable evidence. Preserve invoices, receipts, bank records, vehicle or home-use calculations and the business purpose of mixed expenses for the relevant retention period.

That system does more than prevent a tax bill. It answers the business question that turnover cannot: after costs, GST, personal tax and a deliberate retirement contribution, how much has the side hustle actually created?