2025–26 · ABN · GST · Deductions
Side Hustle Tax Calculator
Calculate the real tax on your freelance or gig income — including whether you need GST, how much to set aside each quarter, and the impact on your HECS repayment.
Your situation
Annual salary (PAYG)
Your day-job income before tax
Gross side hustle revenue
Total income before deductions — what clients pay you
Business deductions
Home office, equipment, professional memberships, etc.
I have a HECS debt
Side income increases your repayment
You need an ABN
Any business income — even from a single client — requires an Australian Business Number. Registering is free at abr.business.gov.au and takes about 10 minutes. Without one, your clients must withhold 47% tax from your invoices.
Your side hustle tax summary
Taxable income
$18,000
after deductions
Tax on side hustle
$5,760
32% effective rate
Net take-home
$12,240
after income tax
Set aside/quarter
$1,440
to avoid a tax bill
No GST registration needed yet
Your gross revenue ($20,000) is under the $75,000 threshold. Voluntary registration is optional but lets you claim GST credits on purchases.
Full tax breakdown
Your side hustle nets $12,240/yr — see how it accelerates your financial plan
Model the impact on your FIRE date and investment projections.
See my full plan →How side hustle tax works in Australia
Side hustle income — freelancing, consulting, selling online, driving for rideshare — is treated as business income by the ATO. It is added to your total taxable income and taxed at your marginal rate. There is no separate category or rate for casual or occasional business income.
Unlike PAYG employment, no tax is withheld on business income. The ATO expects you to manage this yourself — either through quarterly PAYG instalments (triggered automatically once you earn over a certain threshold) or by setting money aside and paying at tax time. Getting this wrong can mean a large, unexpected debt when you file your return.
The ATO's data-matching program now receives transaction data from platforms like Uber, Airbnb, Etsy, and major banks. If you are earning business income without declaring it, the risk of being caught has increased significantly. Declaring honestly and managing your tax quarterly is both legally required and financially sensible.
Frequently asked questions
Do I need an ABN for my side hustle?
Yes — if you are running a business (even part-time), you need an Australian Business Number. If you invoice clients without an ABN, they are legally required to withhold 47% tax from your payment. ABN registration is free at abr.business.gov.au and takes about 10 minutes.
When do I need to register for GST?
You must register for GST once your annual business turnover reaches $75,000. Below that threshold, registration is optional. If you do register, you collect 10% GST on top of your prices and remit it to the ATO quarterly via a Business Activity Statement (BAS).
What can I deduct from my side hustle income?
Common deductions include: home office expenses (hourly rate or floor space method), equipment and tools used for the business, subscriptions and software, professional development directly related to your income, and a portion of phone/internet if used for work. You can only deduct actual expenses — no deductions for time you spend.
How is side hustle income taxed?
Business income is added to your total taxable income and taxed at your marginal rate. If you earn $90,000 from your job and $20,000 from a side hustle, the extra $20,000 is taxed at 32% (the marginal rate above $45,000). The ATO does not have a separate 'side hustle tax' — it is ordinary income tax.
Does side hustle income affect my HECS repayment?
Yes. HECS repayments are calculated on your total income including business income. If your side hustle pushes your income into a higher repayment band, your mandatory HECS repayment increases. This is automatically captured in your tax return — but it's worth setting extra aside each quarter to avoid a large end-of-year debt.
Should I set up a company for my side hustle?
For most side hustles, operating as a sole trader is simpler and cheaper. A company (Pty Ltd) has a 25% or 30% tax rate rather than your marginal rate, which can save tax once income exceeds ~$120,000+ and the admin cost is worthwhile. Below that, the complexity and cost of a company rarely pay off.