Understanding Business Registration Numbers In Australia

Starting a business in Australia is exciting - but it also comes with a few core legal steps you’ll want to get right from the beginning. One of the first concepts you’ll come across is business registration numbers. These identifiers are how government bodies, banks, suppliers and customers recognise your business in official contexts.

If you’re wondering whether you need an ABN, an ACN, or both, you’re in the right place. In this guide, we’ll explain what these numbers mean, who needs them, how to get them, and how to stay compliant once you’re up and running.

By the end, you’ll know exactly which numbers apply to your business structure and how to put simple systems in place so you can focus on building and growing your brand with confidence.

What Is A Business Registration Number In Australia?

In Australia, “business registration number” is a catch-all phrase people use to describe the unique identifiers government agencies issue to entities that carry on an enterprise. In practice, you’ll mainly encounter two numbers:

• Australian Business Number (ABN): An 11‑digit identifier used by businesses of all types (sole traders, partnerships, companies, and trusts) for tax and official dealings.
• Australian Company Number (ACN): A 9‑digit identifier issued by the Australian Securities and Investments Commission (ASIC) to incorporated companies (e.g. Pty Ltd entities).

Not every business has an ACN, but most will have an ABN. If you operate as a company, you’ll have both. If you operate as a sole trader or partnership, you’ll generally only need an ABN.

It’s also worth separating your name from your number. Your legal or trading name is the label customers see; your ABN or ACN is the behind‑the‑scenes identifier. If you trade under a name other than your own legal name, you’ll usually need to register a business name with ASIC and link it to your ABN. For a quick refresher on naming, see the difference between a business name and a company name.

ABN Vs ACN: What’s The Difference?

ABN and ACN often get mentioned together, but they serve different purposes and apply to different structures.

Australian Business Number (ABN)

An ABN is used to identify your enterprise for tax and business purposes. You’ll typically include your ABN on invoices, quotes, and other official communications.

• Who needs an ABN? Businesses carrying on an enterprise in Australia - including sole traders, partnerships, companies and trusts - will generally require an ABN. Whether you’re “carrying on a business” depends on factors such as intention to profit, repetition and system, and the commercial nature of your activities. If you’re unsure where you sit on the hobby vs business spectrum, read what defines a business activity in Australia.
• GST link: There is no separate GST number in Australia. If you register for Goods and Services Tax (GST), your ABN is used for GST purposes.
• Common myth: ABN eligibility isn’t based solely on turnover. Turnover matters for GST registration (many businesses must register at or above the relevant threshold), but your entitlement to an ABN is assessed on whether you’re carrying on an enterprise.

Tax note: GST and BAS obligations depend on your situation. It’s wise to confirm your position with an accountant or tax adviser.

Australian Company Number (ACN)

An ACN is issued by ASIC when you register a company. It’s a legal identifier for that company as a separate entity.

• Who needs an ACN? Only incorporated companies (e.g. proprietary limited companies) receive an ACN. Sole traders and partnerships don’t.
• Display: Companies must show their ACN or (where permitted) their ABN on certain public documents and communications, such as invoices, quotes and formal notices. If your company also has an ABN, you can usually display the ABN in place of the ACN on invoices and receipts.
• Company requirements: When you incorporate, you’ll need to meet additional obligations, like having at least one director who meets Australian resident director requirements and deciding whether to adopt a Company Constitution.

Step‑By‑Step: Getting Your ABN And/Or ACN

Registering the right number is straightforward once you know your structure. Here’s a simple roadmap.

1) Choose Your Structure

Your structure determines which registration number(s) you’ll hold.

• Sole trader: You trade as an individual with an ABN. There’s no ACN because you’re not a company.
• Partnership: Two or more people (or entities) run the business together. The partnership will generally hold an ABN. No ACN unless you incorporate a company as part of the structure.
• Company (Pty Ltd): A separate legal entity registered with ASIC. The company gets an ACN on registration, and you’ll also apply for an ABN for tax and invoicing.
• Trust: The trust will typically need an ABN, and if a company acts as trustee, that company will have an ACN too.

There’s no one-size-fits-all choice. Many small businesses begin as sole traders for simplicity, while others choose a company early to access limited liability and a clearer path to investment and growth. If you have co‑founders, it’s a strong sign to consider a company and put a Shareholders Agreement in place.

2) Apply For Your ABN

Most businesses carrying on an enterprise in Australia can apply for an ABN online. You’ll be asked for basic details, including your structure, business activities and start date, plus any business names you intend to use.

Once issued, your ABN becomes public record information - which makes it easy for customers and suppliers to check your status. This transparency builds trust and reduces friction when you open a business bank account, sign up with suppliers, or apply for payment gateways.

Tip: If you’re setting up a company, you can apply for the ABN after you receive your ACN, or as part of a combined process depending on your provider.

3) Register A Company (If Incorporating)

If you decide to incorporate, you’ll register your company with ASIC. You’ll receive your ACN at completion. You’ll also make decisions about your company’s rules (replaceable rules vs a custom Company Constitution), appoint directors, and issue initial shares.

After your ACN is issued, you’ll apply for an ABN and link your chosen business name if you plan to trade under a name that is different from your company’s legal name.

4) Register A Business Name (If You Need One)

If your trading name is different from your legal name (for example, you’re a sole trader John Smith trading as “Smith Design”), you’ll generally need to register that business name and link it to your ABN. A business name registration lasts one or three years and must be renewed to keep it active.

Remember, a business name isn’t a separate legal entity - it’s simply a name under which you trade. Your legal obligations and liabilities still sit with the underlying person or entity.

How To Find Or Verify A Business Registration Number

There are a few straightforward ways to check ABN or ACN details when you’re doing due diligence on a supplier, partner or contractor, or when you’re confirming your own details are recorded correctly.

• Public registers: ABNs and company details can be searched on public registers. You can search by name or by number to confirm whether an entity is active, who the underlying entity is, and (for companies) whether they’re registered or deregistered.
• Official documents: Most businesses display their ABN or ACN on invoices, quotes, letterheads, and sometimes in their website footer or email signature. If you can’t find it publicly, ask the business to provide it on their invoice before you proceed.
• Contracts: For larger deals, it’s common to verify details against a company extract as part of due diligence, so your contract references the correct legal entity and number.

Verifying registration details before you sign can help you avoid dealing with the wrong entity, reduce the risk of non‑payment, and keep your records audit‑ready.

Ongoing Compliance And Display Rules

Getting your number is step one. From there, it’s about maintaining accurate records and using your number appropriately.

Display Requirements

• Companies: Companies must include their ACN (or, in many cases, their ABN) on certain public documents and communications. As a rule of thumb, ensure your number appears on invoices, receipts, quotes, formal notices and other official stationery. If your company has an ABN, using the ABN on invoices/receipts is usually acceptable.
• Other entities: Sole traders, partnerships and trusts commonly include their ABN on invoices, quotes and websites. This helps customers and suppliers verify who they’re dealing with.

Keep Your Details Up To Date

• ABN details: If your contact details, business activities or structure change, update your ABN record promptly so government agencies and other businesses can find correct information.
• Business name renewals: Business names must be renewed every one or three years. If you stop using a name, you can let it lapse or cancel it.
• Company annual review: Each year, companies go through an ASIC annual review process. You’ll receive a statement, confirm details (directors, addresses, shareholdings), and pay an annual review fee. There is no “company renewal” in the sense of re‑registering the entity - but you must complete this review to remain in good standing.

Tax And Accounting Considerations

• GST and BAS: If you’re registered for GST, you’ll lodge Business Activity Statements (BAS) at the required intervals. If you cross the relevant turnover threshold, GST registration may be compulsory.
• Seek professional advice: Because tax obligations depend on your specific circumstances, speak with a qualified accountant or tax adviser about GST registration, BAS cycles, payroll obligations and record‑keeping.

Protect Your Business With Essential Legal Documents

Once your registrations are in place, it’s smart to protect your daily operations with clear, tailored contracts and policies. These documents help set expectations, reduce risk and build trust.

• Privacy Policy: If you collect personal information (e.g. contact details, email subscribers, online sales), publish a compliant Privacy Policy explaining what you collect and how you use it.
• Website Terms & Conditions: If you have a website or app, Website Terms and Conditions set out acceptable use, IP ownership and liability limits.
• Customer Terms or Service Agreement: For product or service businesses, clear customer terms outline scope, pricing, payment, warranty and liability.
• Employment Contract: If you’re hiring staff, use a compliant Employment Contract and ensure your workplace policies align with Fair Work obligations.
• Supplier/Contractor Agreements: Formalise relationships with your key suppliers and contractors to set service levels, delivery terms and IP ownership.
• Shareholders Agreement: If you’ve formed a company with co‑founders or investors, a Shareholders Agreement clarifies ownership, decision‑making, exits and dispute resolution.
• Trade marks: Protect your brand by registering your name or logo as a trade mark. A trade mark registration can deter copycats and strengthens your position if disputes arise.

If you sell goods or services to consumers, make sure your contracts and marketing comply with the Australian Consumer Law (for example, the rules against misleading or deceptive conduct). If in doubt, get your customer journey and key documents reviewed with the Section 18 obligations in mind.

Key Takeaways

• In Australia, your main “business registration numbers” are your ABN (for most entities) and your ACN (for companies only).
• ABN entitlement depends on carrying on an enterprise, not just turnover, while GST registration is driven by turnover thresholds and business circumstances - check this with your accountant.
• Companies receive an ACN on incorporation and must include their ACN (or, where allowed, their ABN) on key public documents.
• If you trade under a name other than your legal name, register that business name and link it to your ABN; remember a name is not a separate legal entity.
• Keep your details current: update ABN records, renew business names, and complete ASIC’s annual company review to stay compliant.
• Strengthen your foundation with clear contracts and policies, such as a Privacy Policy, Website Terms, Employment Contracts, supplier agreements and (for companies) a Shareholders Agreement.
• Verifying ABN/ACN details before you sign with a new supplier or partner is a simple way to avoid mistakes and build trust.

If you’d like a consultation on business registration numbers and setting up your Australian venture with the right structure and documents, you can reach us at 1800 730 617 or team@sprintlaw.com.au for a free, no‑obligations chat.