What Is a Business Registration Number in Australia?

Starting a business in Australia is exciting, but the paperwork can feel confusing at first - especially when you’re faced with terms like ABN, ACN and business name registration.

If you’ve ever wondered “what is a business registration number in Australia?”, you’re not alone. The short answer is that there isn’t just one number for every business - what you need depends on your structure and how you plan to operate.

In this guide, we’ll break down the key numbers you might need (and what they mean), how to get them step-by-step, and the legal documents and compliance obligations to consider as you grow. By the end, you’ll know exactly which registrations apply to you and how to get set up the right way - without the overwhelm.

In Australia, “business registration number” is an umbrella term people use to describe the unique identifiers attached to a business. Depending on your structure and activities, you may need one or more of the following:

• Australian Business Number (ABN): An 11‑digit identifier used by most businesses - sole traders, partnerships, companies and trusts - to interact with the ATO, issue invoices, register for GST and more. It’s the most common “business registration number.”
• Australian Company Number (ACN): A 9‑digit number issued by ASIC when you register a company under the Corporations Act 2001 (Cth). It identifies your company as a separate legal entity. If you run a company, you’ll have an ACN as well as an ABN (the ABN often incorporates the ACN).
• Business Name Registration: If you trade under a name that isn’t your own personal or company legal name, you must register that business name with ASIC and link it to your ABN. There isn’t a separate “business name number” - the registration is tied to your ABN and appears on the public register. Understanding the difference between a business name vs company name is key here.
• ARBN (Australian Registered Body Number): In some cases (for example, certain incorporated associations operating across state borders or foreign companies registered in Australia), an ARBN is issued by ASIC. Most small businesses won’t need an ARBN, but it exists for specific registered bodies.

So when someone says “my business registration number,” they usually mean their ABN. If they’ve set up a company, they’ll also have an ACN (and the ABN will be in the company’s name).

Do You Need an ABN, ACN or Both?

In practice, most Australian businesses will need an ABN. Whether you also need an ACN depends on whether you choose a company structure. Here’s how it works by structure:

• Sole trader: Apply for an ABN in your personal name. If you trade under a different business name, register that name and link it to your ABN.
• Partnership: The partnership obtains its own ABN (separate from the partners’ personal ABNs). If trading under a specific name, register the business name to that partnership ABN.
• Company: When you register a company with ASIC, you’ll receive an ACN. You then obtain an ABN for the company. The company’s legal name is separate to any business name you also choose to register.
• Trust: The trustee (an individual or company) applies for an ABN for the trust. If the trustee is a company, that company will also have an ACN.

Is an ABN legally required in all cases? Not strictly - but operating without one is impractical. Suppliers may be required to withhold tax at the top rate if you don’t quote an ABN on invoices, you can’t register for GST, and many customers and platforms will expect an ABN to onboard you. It’s one of the first steps to trading smoothly and being taken seriously.

If you decide to operate as a company, an ACN is mandatory. Companies must also meet director and governance obligations, including having at least one Australian resident director (see Australian resident director requirements if you plan to incorporate).

One common point of confusion is the difference between an entity’s legal name and the business name you use in marketing. A company might be registered as “Smith Holdings Pty Ltd” but trade as “Sunshine Fitness” - the latter is the business name. If you’re unsure which you need, it helps to clarify business name vs company name early.

How To Get Your Business Registration Number (Step-By-Step)

Every business is different, but most new ventures follow a similar sequence. Here’s a simple path to follow.

Step 1: Choose Your Business Structure

Think about risk, tax, growth plans and ownership. Many founders start as a sole trader to keep things simple, while others incorporate a company from day one to separate personal assets and prepare for growth or investment.

If a company is right for you, you can complete the process online - a Company Set Up includes registration with ASIC, allocation of shares and key governance documents.

Step 2: Apply for an ABN

Once you’ve settled on a structure, apply for your ABN with the Australian Business Register. You’ll need basic details about your activities, structure and start date. If you’ve registered a company, apply for an ABN in the company’s name after receiving your ACN.

Tip: Keep your ABN details up to date. If your structure or contact information changes, review and update your record. You can also check whether a supplier’s ABN is active using public lookup tools.

Step 3: Register Your Business Name (If You’re Using One)

If you plan to trade under a name that’s not your personal name or your company’s legal name, register that name with ASIC and link it to your ABN. You can do this via ASIC’s online portal, or ask us to handle a Business Name registration alongside your other setup tasks.

Step 4: Set Up Tax Registrations

Register for GST if your turnover is, or is likely to be, $75,000 or more in a 12‑month period. You may also need PAYG withholding if you hire employees, and you’ll need to meet superannuation obligations.

Note: Tax requirements can vary with your structure and industry. It’s worth getting tailored accounting or tax advice to make sure you’ve registered for everything you need.

Step 5: Put Your Foundations in Place

Set up a separate business bank account, choose accounting software, and get essential legal documents in order (more on those below). If you’re forming a company with co‑founders, consider a Shareholders Agreement to set clear rules around ownership, decision‑making and exits from day one.

Staying Compliant After You Register

Securing your ABN (and ACN, if relevant) is just the beginning. Ongoing compliance helps you avoid penalties and build trust with customers and partners.

Australian Consumer Law (ACL)

If you sell goods or services, you must comply with the ACL - including consumer guarantees, fair refunds and not engaging in misleading or deceptive conduct. Everyday marketing and pricing claims are regulated, so review your ads and website against your obligations under section 18 (misleading or deceptive conduct) of the ACL. For a practical overview, see Sprintlaw’s guide to section 18.

Employment Law

Hiring staff triggers obligations under the Fair Work Act 2009 (Cth) and relevant awards. You’ll need compliant Employment Contracts, correct pay and entitlements, superannuation, payslips, and adherence to the National Employment Standards. The Fair Work Ombudsman publishes guidance on awards, overtime and rostering - but it’s wise to get advice if you’re unsure which award applies.

Privacy and Data Protection

Many small businesses collect personal information (for example, through online forms, orders or email lists). The Privacy Act 1988 (Cth) generally applies to businesses with an annual turnover of more than $3 million, but there are key exceptions - such as health service providers or businesses that trade in personal information - where it applies regardless of turnover.

Even if you’re under the threshold, customers expect transparency. Publishing a clear, tailored Privacy Policy and safeguarding customer data is best practice and can prevent disputes.

Website and Platform Terms

If you sell online or operate a platform, your site should set the ground rules. Website Terms and Conditions outline acceptable use, IP ownership, limitations of liability and dispute processes. If you take payments or subscriptions, you’ll also need robust product or service terms.

Licences and Permits

Depending on your industry, you may need local council approvals, health or safety permits, or professional registrations. Check both state and local requirements - failing to obtain a required licence can lead to fines or being shut down temporarily until you’re compliant.

Company Governance (If You Incorporated)

Companies must keep ASIC details up to date, maintain registers and records, and meet director duties. If you move address or change directors, update your ASIC record promptly. Keep your internal governance documents (like your constitution and shareholder records) organised and current.

Finance and Record Keeping

Accurate records are essential. Keep invoices, receipts and payroll records for the required time periods and reconcile your accounts regularly. If you’re registered for GST, ensure your BAS submissions are on time and accurate.

Essential Legal Documents To Put In Place

Your registrations identify you, but your contracts protect you. Here are the core documents most new Australian businesses should consider.

• Customer Contract or Terms: Set the rules for your sales or services - pricing, scope, delivery, warranties, refunds and limitations of liability. This can be a proposal that converts on acceptance, or standard online terms for e‑commerce and bookings.
• Privacy Policy: Explain how you collect, use and protect personal information, and how customers can contact you about privacy. A tailored Privacy Policy helps with transparency and compliance.
• Website Terms and Conditions: For online businesses, Website Terms and Conditions set expectations for users, cover IP and content rules, and outline acceptable use.
• Employment Contracts: If you hire staff, Employment Contracts clarify duties, hours, remuneration, termination and confidentiality. If you engage contractors, use a proper Contractor Agreement instead.
• Shareholders Agreement (if you have co‑founders): A Shareholders Agreement covers ownership, decision‑making, vesting, exits and dispute resolution, so you’re aligned for the long term.
• Supplier or Service Agreements: Lock in quality, delivery, timelines, pricing and risk allocation with key suppliers and service providers. Clear contracts reduce disputes and supply chain surprises.
• Non‑Disclosure Agreement (NDA): Use NDAs to protect confidential information when you discuss your business with potential partners, investors or vendors.

Not every business will need every document on day one, but most will need several. Getting the right terms in place early is a simple way to prevent misunderstandings and set professional expectations with customers, staff and partners.

Common Questions About Business Registration Numbers

Is an ABN the same as an ACN?

No. An ABN is an 11‑digit number used by most businesses to interact with government and invoice customers. An ACN is a 9‑digit number that only companies receive when registered with ASIC. Companies have both an ACN and an ABN (in the company’s name).

Do I always need a business name?

Not if you trade under your own legal name (for a sole trader) or your company’s exact legal name. If you want to trade under a different name, register it with ASIC and link it to your ABN. This is distinct from your company name - see the difference between a business name vs company name.

How do I check if a business is legitimate?

You can look up ABN and business name details using public tools and ASIC’s registers. It’s also smart to check if an ABN is currently active, and whether the business has registered the name it uses publicly before you sign anything or pay a deposit.

When should I register for GST?

You must register when your turnover is, or is likely to be, $75,000 or more in a 12‑month period. Some industries (like rideshare) require GST regardless of turnover. Because GST and PAYG obligations depend on your activities, speak with your accountant for tailored advice.

Can I start as a sole trader and switch to a company later?

Yes. Many founders start as a sole trader while testing their idea, then incorporate a company for limited liability, brand credibility or investment readiness. When you switch, you’ll need to transfer contracts, update registrations and set up the new company’s ABN and bank accounts.

Key Takeaways

• “Business registration number” usually refers to your ABN. If you register a company, you’ll also have a 9‑digit ACN issued by ASIC.
• Most Australian businesses should apply for an ABN early; operating without one creates practical issues with invoicing, GST and onboarding suppliers or customers.
• If you incorporate, meet company obligations (ACN, ASIC records, resident director requirements and proper governance) and consider a Shareholders Agreement if you have co‑founders.
• Stay compliant with the Australian Consumer Law, employment laws under the Fair Work Act, and privacy obligations - even small businesses benefit from a clear Privacy Policy and solid website terms.
• Protect your business with fit‑for‑purpose contracts: customer terms, Website Terms and Conditions, Employment Contracts, supplier agreements and NDAs.
• Register the right name the right way - understand business name vs company name - and link any business name to your ABN.

If you’d like a consultation on business registration numbers or getting your business set up the right way in Australia, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no‑obligations chat.