To register an ABN as a sole trader, apply for free at the Australian Business Register (abr.gov.au) — select "Individual / Sole Trader", enter your Tax File Number and a specific business activity description, and most applications are approved instantly with the number issued the same day. It costs nothing, takes 10-15 minutes, and you can register for GST in the same form. Below is the full step-by-step, the figures that are current for the 2025-26 financial year, and the common mistakes that delay approval.
An Australian Business Number (ABN) is a unique 11-digit identifier issued by the Australian Business Register (ABR). It's how the government, other businesses, and the tax system identify your business. Think of it as your business's ID number.
As a sole trader, your ABN is linked directly to your individual Tax File Number (TFN), but it's a separate number used specifically for business dealings.
You need an ABN if you're carrying on a business in Australia. The key word here is "business" — the ATO distinguishes between a hobby and a business based on several factors:
- You have a genuine intention to make a profit
- You operate in a businesslike manner (keeping records, having a plan)
- You repeat and regularly engage in the activity
- The activity is of a commercial nature
If you're a freelancer, contractor, tradesperson, or anyone offering goods or services commercially, you almost certainly need an ABN.
- You're a freelance designer, developer, writer, or consultant
- You're a tradesperson working for yourself (plumber, electrician, builder)
- You drive for rideshare platforms or deliver food as a contractor
- You sell products online through your own store
- You provide professional services (bookkeeping, photography, coaching)
- You're an employee (your employer handles tax)
- Your activity is a hobby with no genuine profit intention
- You earn less than $75 per engagement in specific circumstances
If you provide services to a business without quoting an ABN, they are legally required to withhold 47% of your payment and send it to the ATO. This is called "no ABN withholding" and it's a significant hit to your cash flow.
You can claim this withheld amount back when you lodge your tax return, but you'll be out of pocket until then. Getting an ABN avoids this entirely — and it lets you put a valid ABN on every invoice, which is a requirement for a compliant tax invoice in Australia.
Before you apply, confirm that you're entitled to an ABN. You're eligible if you're:
- An Australian resident carrying on a business
- A non-resident carrying on a business in Australia
- About to start a business in Australia
You'll need the following to complete the application:
- Your Tax File Number (TFN)
- Your full legal name and date of birth
- Your residential address
- Your business activity description — what your business does
- Your business address (can be your home address for sole traders)
- The date you started (or expect to start) your business
- Your expected annual turnover estimate
Go to the Australian Business Register website at abr.gov.au and click "Apply for an ABN." The application is free and typically takes 10-15 minutes. Be wary of third-party sites that charge a "registration fee" — registering directly with the ABR never costs anything.
You'll need to:
- Select your business structure — choose "Individual / Sole Trader"
- Enter your personal details and TFN
- Describe your main business activity (be specific — "IT consulting" is better than "services")
- Provide your business and postal addresses
- Nominate an ABN start date
- Choose whether to register for GST at the same time (required if turnover is $75,000 or more)
Most sole trader applications are processed immediately and you'll receive your ABN on screen. In some cases — for example trusts, partnerships, or non-residents — the ATO may need to review the application manually, which can take up to 28 days.
Save or print your ABN confirmation. You'll also receive written confirmation from the ABR. You can verify your own ABN (or a supplier's) any time with a free ABN lookup tool.
When applying for your ABN, you'll be asked whether you want to register for GST.
- You must register for GST if your annual turnover is or will be $75,000 or more
- You can voluntarily register if your turnover is under $75,000
Voluntary registration means you charge 10% GST on sales and can claim GST credits on business purchases. It can make sense if most of your expenses include GST, but it adds quarterly BAS lodgement obligations. If you're unsure how much GST you'd be adding to a price, work it out with a free GST calculator before you decide.
If you're earning hobby income (selling occasional crafts, doing one-off favours), an ABN isn't appropriate. The ATO may cancel ABNs that were incorrectly issued.
Sole trader is the simplest structure, but it's not always the best. If you have partners, consider a partnership. If you want liability protection, consider a company. This decision affects tax, liability, and legal obligations.
"Consulting" or "services" is too generic. Be specific: "IT infrastructure consulting" or "residential plumbing services." This helps the ATO classify your business correctly and reduces the chance of a manual review delay.
If you change your address, business activity, or contact details, you must update your ABR record within 28 days. Outdated records can cause issues with GST, PAYG, and government communications.
Your ABN and your business name are different things. If you trade under any name other than your own legal name, you need to register a business name through ASIC (Australian Securities and Investments Commission). As of the 2025-26 financial year this costs $47 for one year or $108 for three years.
Start issuing professional invoices that include your ABN. If you're registered for GST, these must be tax invoices meeting ATO requirements — the word "Tax Invoice", your ABN, the GST amount, and the date are all mandatory.
While not legally required for sole traders, a separate business bank account makes bookkeeping dramatically easier and gives your business a more professional appearance.
As a sole trader, your business income is declared on your personal tax return. You'll need to keep records of all income and expenses, and you may need to make quarterly PAYG instalments if the ATO assesses that you'll owe tax.
Track income and expenses from day one. Retroactively reconstructing records at tax time is painful, inaccurate, and stressful.
OneBookPlus is built in Australia for exactly this moment — you've just registered your ABN and you need a professional, compliant way to run the business without stitching five apps together. It's an all-in-one platform (invoicing, quotes, bookings, jobs, CRM and accounting) that's GST- and ABN-native and hosted on AWS in Sydney, with a genuinely free plan to start on:
- Professional tax invoices with your ABN and GST shown automatically the way the ATO expects
- Expense tracking from day one so nothing gets lost before tax time
- GST calculations built into every invoice and quote (if you're registered)
- Client and job management to keep customer details, quotes and work organised in one place
- Flat, predictable pricing with a $0 free plan that covers everything a new sole trader needs
If you're starting out solo, the OneBookPlus for freelancers and sole traders guide walks through how it fits a one-person business.
Apply for free at the Australian Business Register (abr.gov.au), choose "Individual / Sole Trader", and supply your Tax File Number, a specific business activity description, and your address. Most applications are approved instantly and the ABN is issued the same day.
An ABN is completely free when you apply directly through the ABR. Avoid third-party sites that charge a service fee. A separate ASIC business name (only needed if you trade under a name other than your own) costs $47 for one year or $108 for three years.
Only if your turnover is or will be $75,000 or more — then GST registration is compulsory. Below that threshold it's optional. You can register for GST in the same ABN application, or add it later.
Don't wait until tax time to get organised. Start free with OneBookPlus and put a compliant, ABN-ready invoice in front of your first client today.
