Is An ABN A Legal Requirement?

Starting or growing a business in Australia often begins with a simple question: do you actually need an Australian Business Number (ABN)? It’s a fair question, especially if you’re testing a new idea, freelancing on the side, or running a small online store.

In this guide, we’ll break down when an ABN is legally required, when it’s optional, and what happens if you operate without one. We’ll also cover how an ABN fits alongside other registrations (like business names, companies and GST) so you can make the right call for your situation.

Our goal is to make the rules clear in plain English, so you can focus on building your business with confidence.

What Is An ABN?

An Australian Business Number (ABN) is a unique 11-digit identifier issued by the Australian Business Register for businesses operating in Australia. It’s used across many parts of your business life - invoices, dealings with suppliers, tax and GST, applying for licences, and more.

The ABN is not a business structure, and it’s not the same as a business name or company registration. Think of it as a public identifier that tells others “this activity is a business.”

If you’re weighing up whether an ABN is right for you, it can help to consider the advantages and disadvantages of having an ABN in light of your plans and risk profile.

Is An ABN A Legal Requirement In Australia?

In short: if you are carrying on an enterprise (that is, running a business) in Australia, you are expected to have an ABN. If you’re not carrying on a business - for example, you’re pursuing a genuine hobby and not seeking to make a profit - then you generally don’t need an ABN.

How Do You Know If You’re “Carrying On A Business”?

There isn’t one magic test, but common indicators include: a profit-making intention, operating in a business-like way, regular or repeated activities, and marketing or promoting what you offer. If this sounds like what you’re doing, it’s safer to assume you need an ABN.

To help you assess your situation, it’s worth understanding what defines a business activity - this can clarify when an activity crosses over from hobby to business.

When It’s Not Required

If your activities are truly a hobby (for example, occasionally selling personal items or making the odd craft sale without a business-like setup), an ABN is typically not required. However, as soon as you start invoicing regularly, advertising, or scaling operations, you’re moving into “business” territory.

Who Must Have An ABN (And Who Might Not)?

Sole Traders, Freelancers and Contractors

If you’re a sole trader or contractor and you invoice for your services, you generally need an ABN. Without one, payers may be required to withhold tax at the top marginal rate from your payment.

Many individuals choose to work under an ABN because it gives them flexibility and access to business tools; you can read more about the benefits of working under an ABN if you’re freelancing or consulting.

Partnerships, Companies and Trusts

Partnerships, companies and trusts that carry on an enterprise in Australia must have their own ABN. If you’re setting up a trust or company, keep in mind there are other registrations involved (like a company’s Australian Company Number, or ACN) and you’ll typically apply for the ABN as part of those steps. For context, see our overview of trust requirements in Australia (ABN, ACN, TFN).

Not-For-Profits

Not-for-profit organisations and charities often need an ABN to access tax concessions and to interact with government and donors. Whether they must have an ABN will depend on their activities and structure, but it is commonly required for operational reasons.

Side Hustles and Hobbies

If you’re earning only sporadic income from a hobby, and you aren’t operating in a business-like way, you may not need an ABN. But once you start selling with an intention to profit or scale, the position changes. When in doubt, it’s prudent to register.

What Happens If You Operate Without An ABN?

Running a business without an ABN can create practical and tax headaches:

• Clients may be required to withhold tax from your payment at the top marginal rate if you don’t quote a valid ABN on invoices.
• You may find it difficult to open trade accounts, apply for licences, or sign up with suppliers or marketplaces that require an ABN.
• It can be harder to demonstrate legitimacy with business partners and customers.

There are some scenarios where people try to operate without one - for example while “testing” a concept - but this is risky if your activity meets the business tests. We explain the traps and alternatives in more detail here: run a business without an ABN.

ABN, ACN And Business Names: What’s The Difference?

It’s easy to mix these up, but they do different jobs.

• ABN: The 11-digit identifier for your enterprise (sole trader, company, partnership or trust) used for tax and business dealings.
• ACN: A 9-digit number for companies only. You get an ACN when you register a company with ASIC (the government regulator for companies). You’ll also apply for an ABN for the company.
• Business Name: The name you trade under if it’s not your personal name or your company’s exact legal name. Registering a business name is separate from the ABN - and it doesn’t create a new legal entity.

If you’re tossing up whether you need a business name or a company (or both), we’ve set out the key differences here: business name vs company name. Understanding this distinction helps you choose the right combination of registrations.

Do You Need An ABN To Register For GST?

Yes. If you need to register for Goods and Services Tax (GST), you must have an ABN. You must register for GST when your GST turnover is $75,000 or more (or if you drive for rideshare/taxi services, you generally need to register regardless of turnover). Even if you’re under the threshold, some businesses opt in early for operational reasons.

An ABN is also used for other tax interactions - lodging BAS statements, dealing with PAYG withholding (if you hire employees), and communicating with the ATO.

How To Get An ABN (Step-By-Step)

Applying for an ABN is usually straightforward and free, and can be done online. Your steps will differ slightly depending on your structure (sole trader, company, partnership, trust).

1) Choose Your Business Structure

Before you apply, decide whether you’ll operate as a sole trader, partnership, company or trust. Each structure carries different risk, tax and administrative implications.

• Sole Trader: Simple and low cost, but you’re personally liable for business debts.
• Partnership: Two or more people (or entities) in business together. Partners are typically jointly liable.
• Company: A separate legal entity with limited liability, more formalities, and a director responsible for governance.
• Trust: A trustee holds assets for beneficiaries; can be useful for asset protection and tax planning but adds complexity.

If you’re considering a company, factor in director obligations and residency rules. A quick primer on Australian resident director requirements can help you plan properly from day one.

2) Prepare Your Details

Have your personal details (and co-owners’ details if applicable), the nature of your activities, business address, and any relevant dates ready. If applying for a company or trust, you’ll also need details about officeholders or the trust deed.

3) Apply Online

Submit your application and ensure your information is accurate. Most ABNs are issued quickly. If your application is declined because it appears you’re not carrying on an enterprise yet, you can reapply once your activities meet the criteria.

4) Confirm Your ABN Is Active

After approval, check that your ABN is live and your public details are correct. Here’s a quick way to check if an ABN is active and what the status fields mean.

Invoices, Quotes And Everyday Use Of Your ABN

Once you have an ABN, include it on invoices and other key documents. If you’re registered for GST, ensure your invoices meet tax invoice requirements and that your ABN appears clearly.

Suppliers and clients will often ask for your ABN when setting up new accounts. Some industry licences, grants and government programs also require an ABN for eligibility.

Does An ABN Expire? And When Should You Update It?

ABNs generally do not expire, but they can be cancelled if your business ceases or your details are out of date. If you pause trading for a long period or restructure, you may need to update or cancel and reapply. We answer common questions here: does an ABN expire and what to do if circumstances change.

It’s also important to keep your public ABN profile current (address, business activities, entity type). Mismatched details can cause delays with banks, suppliers and government bodies.

ABN FAQs: Common Scenarios We See

“I’m Selling Occasionally - Do I Need An ABN?”

If it’s genuinely irregular and hobby-like (no real intention to profit, no system or routine), you may not need one. But if you’re advertising, taking orders, or planning to grow, you’re likely “in business” and should register.

“I’m A Contractor And My Client Says I Must Have An ABN.”

That’s common. As a contractor, you typically need an ABN. Without one, your payer may need to withhold tax. Registering avoids this and also makes your operations cleaner from a tax and compliance perspective.

“I Have A Company - Do I Still Need An ABN?”

Yes. A company has an ACN for company law purposes and an ABN for tax and business purposes. You’ll usually get both when you set up a company. If you’re still deciding between a business name and a company, this comparison may help: business name vs company name.

“Can I Start Without An ABN And Get One Later?”

Technically you can, but if you’re already carrying on a business, you should not delay. Operating without an ABN can trigger withholding by clients and may complicate your tax position. If you’re on the fence, here’s what to consider about trying to operate without an ABN.

“Where Does My ABN Fit With Trusts And Other Registrations?”

Trusts, companies and partnerships all obtain their own ABNs if they carry on an enterprise. If you’re mapping out a structure that includes a trust, this overview of ABN, ACN and TFN requirements for trusts is a handy starting point.

Beyond Your ABN: A Few Legal Essentials To Cover

Registering for an ABN is a foundational step, but it’s only one part of getting your legal setup right. Depending on how you operate, you may also need:

• Business Name Registration: If you trade under a name other than your personal name or company name, you must register that business name. This is separate from your ABN.
• Customer Terms: Clear terms for your services or online sales (e.g. Terms and Conditions) so customers know pricing, refunds, delivery and liability rules.
• Privacy Policy: If you collect personal information (most businesses do), you’ll need a Privacy Policy that explains what you collect and how you use it.
• Website Terms: If you run a website or app, Website Terms of Use help set the ground rules for visitors and limit your risk.
• Employment Contracts: If you hire staff, use a compliant Employment Contract and ensure your workplace policies and Fair Work obligations are in place.
• Shareholders Agreement: If you’ll have co-founders or investors, a Shareholders Agreement sets expectations around decision-making, equity and exits.

You don’t need every document on day one, but having the right ones in place early can prevent disputes and support growth. If you’re unsure where to start, we can help you prioritise what’s essential for your model.

Key Takeaways

• If you’re carrying on a business in Australia, an ABN is generally required; true hobbies usually don’t need one.
• Operating without an ABN can trigger tax withholding by clients and make everyday business tasks harder.
• An ABN is different from an ACN and from a business name - many businesses need a combination of these registrations.
• You’ll need an ABN to register for GST and to interact with the ATO for BAS and other obligations.
• Applying for an ABN is quick, free and done online, but choose your structure (sole trader, company, trust, partnership) first.
• Beyond your ABN, protect your venture with core documents like a Privacy Policy, Website Terms, Employment Contracts and a Shareholders Agreement if you have co-founders.

If you’d like a consultation on ABNs and getting your Australian business set up correctly, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no-obligations chat.