How to Register for an ABN in Australia: A Step-by-Step Guide for New Business Owners
Starting a business in Australia? An ABN is one of the first things you'll need. Here's how to register for one — for free, in minutes — and what to do once you have it.
Starting a business in Australia comes with a to-do list that can feel overwhelming. Registering for an ABN doesn’t have to be one of the stressful parts. It’s free, it’s quick, and once you understand what’s involved, you can have your ABN in minutes.
This guide walks you through what an ABN actually is, whether you need one, and exactly how to get it — no jargon, no fuss.
What is an ABN?
An Australian Business Number is a unique 11-digit number that identifies your business to the government, other businesses, and the public. Think of it as your business’s ID card. You’ll use it on invoices, when dealing with suppliers, on tax returns, and when registering for things like GST.
Your ABN is public — anyone can look it up on the Australian Business Register to verify your business is legitimate. That might sound intimidating, but it’s actually a good thing. It builds trust with clients and suppliers who want to know they’re dealing with a real, registered business.
Do you actually need one?
Not every side hustle or hobby requires an ABN, but if you’re running a business — or planning to — you almost certainly do.
You need an ABN if you’re carrying on an enterprise (the ATO’s term for running a business) in Australia. This includes sole traders, partnerships, companies, and trusts. You also need one if your GST turnover is $75,000 or more per year, since GST registration requires an ABN.
You don’t need an ABN if you’re an employee (even if you work for multiple employers), earning money from a hobby that isn’t a business, or receiving income purely from investments as an individual.
The grey area is where things get interesting. If you’re freelancing on the side while working a day job, or selling things online regularly, you’re probably running a business in the ATO’s eyes. The key factors they look at include whether you’re operating with a profit motive, whether you have regularity and repetition in your activities, and whether you have a business plan or system in place.
When in doubt, applying for an ABN is free — so there’s little downside to registering if you think you might need one.
What happens if you don’t have one?
Here’s the practical consequence: if a business pays you and you haven’t quoted an ABN, they’re legally required to withhold 47% of your payment and send it to the ATO. That’s a significant hit to your cash flow, even if you eventually get it back when you lodge your tax return.
Having an ABN also lets you register for GST (if needed), issue proper tax invoices, and claim GST credits on business purchases. Without one, you’re essentially operating with one hand tied behind your back.
How to register — step by step
The whole process is online and usually takes about 15-20 minutes if you have your details ready.
Before you start
Gather these details so you’re not hunting for them mid-application. You’ll need your tax file number (TFN), your business details including the type of business structure you’re registering (sole trader, company, partnership, or trust), your business address, a description of your main business activity, and the date your business started (or will start).
If you’re registering a company, you’ll also need your Australian Company Number (ACN) from ASIC.
The application
Head to the Australian Business Register and start your application. You can also go through the Business Registration Service which lets you register for an ABN, business name, and tax registrations all in one go — a handy shortcut if you need more than just an ABN.
The form will walk you through confirming your identity (usually via your TFN), selecting your business structure, entering your business details and activities, and choosing any additional registrations you want at the same time.
If the system can verify your identity from the information you provide, you’ll often receive your ABN immediately at the end of the application. If it needs manual review, the ATO aims to process it within 20 business days.
What it costs
Nothing. Registering for an ABN is completely free through the government’s official channels. If you come across a website charging you for ABN registration, walk away — they’re a third-party service adding unnecessary fees for something you can do yourself in minutes.
What to do once you have your ABN
Getting your ABN is just the starting line. Here’s what comes next.
Decide on your business structure. If you haven’t already, make sure you’ve chosen the right structure — sole trader, company, partnership, or trust. Each has different tax implications, liability exposure, and reporting requirements. Our guide on sole trader vs. company structures can help you think through the options.
Register for GST if you need to. If your annual turnover is (or will be) $75,000 or more, you must register for GST. Even below that threshold, voluntary registration can make sense in some situations — especially if you’re making large purchases and want to claim GST credits. Read our complete GST guide for the full breakdown.
Set up your books from day one. The single best thing you can do for your future self is to start tracking income and expenses properly from the very beginning. Trying to reconstruct a year’s worth of transactions at tax time is painful and error-prone. Good accounting software can automate most of this — bank feeds pull in transactions, and smart categorisation handles the repetitive work. Check out our guide on how to choose accounting software if you haven’t picked a tool yet.
Understand your BAS obligations. Once you’re registered for GST, you’ll need to lodge Business Activity Statements — usually quarterly. It’s not as scary as it sounds, especially if your books are up to date. Our plain-English BAS guide covers everything you need to know.
Register a business name (if needed). Your ABN and your business name are two different things. If you want to trade under a name that isn’t your own personal name, you’ll need to register a business name through ASIC. This is a separate process from your ABN registration (though you can do both at once through the Business Registration Service).
Common questions
Can I have more than one ABN? No. Each entity gets one ABN. If you’re a sole trader, you have one ABN for all your business activities. If you also run a company, the company has its own separate ABN.
What if my details change? You’re required to update your ABN details within 28 days of any changes — things like your business address, contact details, or the nature of your business activities. You can do this through the Australian Business Register.
Can I cancel my ABN? Yes. If you stop running your business, you should cancel your ABN. Keeping an inactive ABN registered can sometimes create complications, and the ATO may cancel it themselves if you haven’t lodged any activity for a while.
How long does an ABN last? Indefinitely, as long as you’re still operating a business and keeping your details up to date. There’s no renewal process.
The bottom line
Registering for an ABN is one of the simplest steps in starting a business. It’s free, it’s fast, and it unlocks everything else — from issuing invoices to registering for GST to building credibility with clients.
Don’t overthink it. Get your details together, spend 15 minutes on the application, and move on to the parts of your business that actually need your energy. Your future self (especially at tax time) will thank you for getting the admin sorted early.