ABN & Sole Trader Tax Guide Australia: Everything You Need to Know

A sole trader is the simplest business structure in Australia — you operate the business in your own name and are personally liable for all debts and obligations. To start, you need an Australian Business Number (ABN), which you can apply for free through the Australian Business Register at abr.gov.au.

The application takes about 10 minutes and your ABN is usually issued immediately. You don't need to register a business name if you operate under your own name (e.g., 'John Smith Consulting'), but you do need to register a business name through ASIC ($39 for one year or $92 for three years) if you want to trade under a different name. Sole traders use their personal Tax File Number for tax purposes — there's no separate entity.

This means your business income and expenses are reported in your individual tax return, and you pay tax at your personal marginal rate. That's the key takeaway.

In plain English: As a sole trader, your business profit (income minus expenses) is added to any other income you earn (such as salary from employment) and taxed at your marginal tax rate. You don't get the benefit of the company tax rate — sole traders pay personal income tax rates up to 45% plus Medicare levy.

However, you may be eligible for the small business income tax offset, which provides up to $1,000 in tax relief for business income up to $75,000. You must lodge your individual tax return by 31 October each year (or later if using a tax agent). If your business has a GST turnover of $75,000 or more, you must register for GST, charge GST on your supplies, and lodge quarterly BAS.

You may also need to make PAYG instalment payments — quarterly prepayments of your expected tax liability — if the ATO determines your annual tax bill is likely to exceed $4,000. This prevents a large tax bill at the end of the year.

Sole traders can claim deductions for all expenses directly related to earning their business income. Common deductions include: home office costs (if you work from home), motor vehicle expenses for business travel, tools and equipment, professional development and training, advertising and marketing costs, professional memberships, accounting and legal fees, insurance (public liability, professional indemnity), subcontractor costs, and depreciation on business assets.

If you use a personal asset for both business and private purposes (such as a phone, laptop, or car), you can only claim the business-use proportion. For cars, you can use either the logbook method or the cents-per-kilometre method (85 cents per km, capped at 5,000 km). Keeping clear records is essential — use accounting software like Xero or QuickBooks to track income and expenses throughout the year rather than scrambling at tax time.

The short version: Unlike employees, sole traders don't receive employer super guarantee contributions. You're responsible for your own retirement savings.

The good news is that personal super contributions made by a sole trader are tax-deductible up to the concessional contributions cap of $30,000 per year (2025-26). This means you can contribute to super and claim a deduction, effectively getting the same tax benefit as salary sacrifice — contributions are taxed at 15% inside super rather than your marginal rate. To claim the deduction, you must lodge a notice of intent with your super fund before lodging your tax return.

Many sole traders neglect super because it feels like an optional expense, but building super contributions into your business budget is critical for long-term financial security. Even contributing $5,000 per year from age 30 can grow to over $500,000 by retirement with compound growth.

The ATO requires sole traders to keep records for at least five years from the date they're prepared or the transaction occurs. Records include invoices issued and received, bank statements, receipts for all expenses, motor vehicle logbooks, and BAS lodgements.

Cloud accounting software is the most efficient way to manage this — it automates bank feeds, GST calculations, and tax reports. Common mistakes sole traders make include: failing to separate personal and business finances (get a dedicated business bank account), not setting aside money for tax (a good rule is to save 25-30% of every payment received), underestimating PAYG instalments, forgetting to charge GST once turnover exceeds $75,000, and not claiming legitimate deductions. Another major mistake is not obtaining appropriate insurance — sole traders are personally liable for all business debts and legal claims.