Australia ABN Sole Trader Tax Calculator (2025-26)

Worked example

Why ABN sole trader tax works differently from a PAYG salary

When you earn a salary as an employee, your employer withholds tax from every pay under the PAYG withholding system, and your take-home pay has already had tax removed. As a sole trader with an ABN, nobody withholds tax for you. You receive the full invoiced amount, and the entire tax bill on your profit falls due after you lodge your return. This is the single biggest cash-flow trap for new sole traders, because the money sitting in your account is not all yours to spend.

The tax itself is not a separate business tax. A sole trader is not a company, so there is no 25% or 30% company tax rate. Instead your business profit is simply added to your personal income and taxed at the ordinary resident individual rates for 2025-26: nothing on the first $18,200, 16% up to $45,000, 30% up to $135,000, 37% up to $190,000, and 45% above that. Your ABN income and any other income (for example a part-time job) are combined, which can push your profit into a higher bracket than you expect.

Because there is no withholding, the ATO uses PAYG instalments to smooth the pain. After your first year of reporting business income, the ATO typically enrols you to pre-pay tax in quarterly instalments based on your prior year figures, rather than in one annual lump sum. Instalments are a pre-payment, not an extra tax; they are credited against your final assessment. Until you are in that system, you carry the full liability yourself.

The practical takeaway is to set aside a fixed percentage of every payment the moment it lands. Our calculator gives you that figure by dividing your total liability (income tax plus the 2% Medicare levy plus any study loan repayment) by your profit. For a typical sole trader on $75,000 of profit that works out around 20 to 21 cents in the dollar, but it climbs steeply once profit passes $135,000 because the 37% and 45% brackets bite. Keeping that money in a separate savings account, ideally one that earns interest, means the quarterly instalment or the annual bill is already covered and you avoid interest charges on late payment. Treat the set-aside percentage as non-negotiable rather than a target you dip into when cash is tight.

The Medicare levy and the tax-free threshold for sole traders

On top of income tax, most Australian resident sole traders pay the Medicare levy of 2% of their taxable income. This is what funds public healthcare, and it is calculated separately from the income tax brackets, which is why the published rate tables note that they exclude Medicare. On a $75,000 profit the levy is a flat $1,500, and on $120,000 it is $2,400. It is easy to overlook because it is not built into the headline marginal rates, yet it is a real and unavoidable cost for the great majority of sole traders.

There is relief at the lower end. For a single person in 2025-26 you pay no Medicare levy if your taxable income is $28,011 or less. Between $28,011 and $35,013 the levy is reduced and phases in at 10 cents for each dollar above the lower threshold, so a sole trader on $30,000 pays only a partial levy rather than the full 2%. Once your income reaches $35,013 the full 2% applies to your whole taxable income. Family thresholds are higher and increase for each dependent child, so a sole trader supporting a family may qualify for a reduction at a higher income than a single person.

The $18,200 tax-free threshold also matters a great deal to sole traders, particularly those running a side business or in their first year. If your profit is below $18,200 and you have no other income, you pay no income tax at all, although you must still lodge a return to report the business activity. Combined with the Medicare levy floor, a very small side hustle can be genuinely tax-free. The trap appears when the ABN income sits on top of a day job: the tax-free threshold is already used up by your salary, so the very first dollar of business profit is taxed at your salary marginal rate, often 30% or more, plus the 2% levy.

Higher earners should also be aware of the Medicare levy surcharge, a separate charge of 1% to 1.5% that applies to individuals earning above $101,000 (for 2025-26) who do not hold an appropriate level of private hospital cover. This calculator estimates the standard 2% levy only and does not include the surcharge, so if your profit is well into six figures and you have no private hospital cover, budget for a little extra or consider taking out cover, which is often cheaper than the surcharge itself.

GST registration at $75,000 and how it affects your ABN

Having an ABN does not automatically mean you charge GST. GST is a separate registration and a separate obligation from income tax. You are required to register for GST once your annual GST turnover (your gross business income, not your profit) reaches $75,000 or more, and you must do so within 21 days of crossing that threshold or of reasonably expecting to. If you drive rideshare or provide taxi travel you must register from the first dollar regardless of turnover. Below $75,000 registration is optional.

Once registered, you add 10% GST on top of your prices, collect it from customers, and remit it to the ATO through your Business Activity Statement (BAS), usually quarterly. Crucially, the GST you collect was never your income. It is money you hold on behalf of the ATO, so it should never be counted in the income figure you type into this calculator, and it should not be spent. In return you can claim back the GST included in your business purchases (input tax credits), so a registered sole trader with significant expenses may find registration works in their favour even before hitting the threshold.

Deciding whether to register voluntarily below $75,000 depends on who your customers are. If you sell mainly to other GST-registered businesses, they simply claim the GST back, so adding 10% does not really cost them and you get to reclaim GST on your own costs. If you sell mainly to consumers or non-registered clients, adding 10% either makes you more expensive or eats into your margin, so many small sole traders stay unregistered until they must. Registering also brings ongoing BAS lodgement and record-keeping obligations, which is a real time cost.

This calculator focuses on your income tax position and deliberately keeps GST out of the tax number, because GST is not a cost to you when handled correctly, it is a pass-through. The key discipline is separation: keep the GST portion of every invoice apart from your own earnings, ideally in its own account, so that when the BAS falls due the funds are ready. Mixing GST money into your working cash is one of the most common reasons sole traders end up owing the ATO amounts they cannot easily find. Treat income tax and GST as two distinct piles from day one and both become manageable rather than alarming.

Cutting your bill: deductions, super and record-keeping

Because a sole trader is taxed on profit rather than turnover, every legitimate deduction directly lowers your taxable income and therefore your tax and Medicare levy. A dollar of genuine business expense in the 30% bracket saves you 32 cents once the levy is counted, and 47 cents in the top bracket. Common deductions include tools and equipment, software subscriptions, professional insurance, phone and internet (business-use portion), accounting and bookkeeping fees, marketing, and travel between jobs. If you work from home you can claim a share of running costs using either the fixed-rate method or actual costs, and motor vehicle expenses can be claimed using the cents-per-kilometre method or a logbook.

Larger purchases may be deductible immediately or depreciated over time depending on the value and the write-off rules in force for the year, so keep receipts for any significant asset and check the current instant asset write-off limit before assuming the full cost is deductible in one year. The golden rule is that the expense must be genuinely incurred in earning your business income, and you must have a record to prove it. Private or domestic costs, and the private portion of mixed-use items, are never deductible.

One deduction sole traders often miss is personal superannuation. Unlike an employee, you are not obliged to pay yourself super, but if you make a personal contribution to your super fund and are eligible, you can generally claim it as a tax deduction up to the annual concessional contributions cap. This both reduces your taxable income now and builds your retirement savings, since no employer is doing it for you. It is one of the few ways to legally shift income out of a high marginal bracket, so it is well worth discussing with an adviser if your profit is comfortably above the tax-free threshold.

Underpinning all of this is record-keeping. The ATO expects you to keep records that explain your income and expenses for at least five years, and a sole trader without clean records cannot safely claim deductions or defend them in a review. Simple habits make an enormous difference: use a dedicated business bank account, keep digital copies of receipts, reconcile monthly, and separate the money you owe (income tax set-aside and any GST) from the money you can actually spend. Doing this turns tax time from a scramble into a formality, and it means the figures you feed into a calculator like this one are accurate rather than a guess. This tool gives an estimate only and is not a substitute for advice from a registered tax agent.

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