ACN Number vs UK Company Registration Number: Key Differences

If you’ve been searching for an “ACN number” while setting up or growing your business, you’re not alone. The term pops up a lot online – but it’s actually an Australian concept. In the UK, you won’t receive an ACN. You’ll get different identifiers, and it’s important to know which number is which, where to find them and when to use them.

In this guide, we’ll demystify what an ACN is, explain the UK equivalents you’ll use day-to-day, and walk through when an ACN might be relevant to you (for example, if you’re expanding into Australia). We’ll also cover where you need to display your numbers to stay compliant and the core legal foundations to sort from day one.

What Is An ACN Number And Why Are You Seeing It?

An ACN (Australian Company Number) is a unique nine-digit number issued by the Australian Securities and Investments Commission (ASIC) to companies registered in Australia. Think of it as the Australian equivalent of a company identifier that appears on a company’s public record, legal documents and invoices.

You’ll often come across “ACN number” in search results because global templates and articles use Australian terms, or because a supplier, customer or investor you’re dealing with is based in Australia.

Key points about ACNs (in Australia):

• Every Australian company receives an ACN on registration with ASIC.
• It must be shown on official documents like invoices, order forms and business correspondence.
• It’s different from an ABN (Australian Business Number), which is a tax identifier used for GST and dealings with the Australian Taxation Office.

If your business is UK-based, you won’t get an ACN. Instead, you’ll have UK identifiers – and using the right one matters for legal compliance here at home.

Do UK Companies Have An ACN Number?

No – UK companies don’t have an ACN. In the UK, the core identifier for a limited company is your Company Registration Number (CRN). This is issued automatically by Companies House when your company is incorporated under the Companies Act 2006.

Your CRN appears on the public register and is the number you’ll use when you file accounts and confirmation statements, open a business bank account, and identify your company on official communications.

Quick facts about UK CRNs:

• They’re eight characters (numbers and sometimes letters, depending on where you registered).
• You’ll find your CRN on your Certificate of Incorporation and on your Companies House listing.
• You should display your CRN on your website, business letters, order forms and invoices to meet disclosure requirements.

If you’re not sure where to find it or how to use it correctly, it’s worth reading a simple overview of Company Registration Numbers.

Still in the planning phase? If you’re registering a new company, our team can guide the process end-to-end to ensure your set-up is compliant – including your CRN, officers, shareholder records and your governance documents. You can start with Register A Company.

ACN vs CRN vs Other UK Numbers: What’s The Difference?

It’s easy to mix up the different identifiers you’ll encounter as a UK business. Here’s a practical breakdown of what each one does and when you’ll use it.

Company Registration Number (CRN) – UK Company Identifier

Your CRN identifies your company on the Companies House register. You’ll use it for corporate filings, banking, contracts, and legal disclosures. You do not need an ACN in the UK – your CRN fills that role.

Unique Taxpayer Reference (UTR) – HMRC Tax Identifier

Your UTR is a 10-digit number issued by HMRC for corporation tax. It’s used for tax returns and correspondence with HMRC. It’s not a public identifier and doesn’t replace your CRN on documents.

VAT Registration Number – When You Register For VAT

If you register for VAT (because you exceed the VAT threshold or choose to register voluntarily), you’ll receive a VAT registration number. This must be displayed on VAT invoices and is used in your VAT returns. It’s separate from your CRN and UTR.

EORI Number – For Import/Export

If you trade goods with the EU or globally, you’ll likely need an EORI (Economic Operators Registration and Identification) number. This helps HMRC and EU customs identify your business for customs purposes. Again, this is different to your CRN.

ACN/ABN/ARBN – For Australian Operations

• ACN: Issued to Australian companies by ASIC.
• ABN: Tax/business identifier issued by the Australian Business Register used for GST and invoicing.
• ARBN: Issued to foreign companies registered to carry on business in Australia.

For UK businesses that operate only in the UK, you don’t need an ACN. If you’re setting up or trading in Australia, you may get an ACN (if you incorporate there) or an ARBN (if you register your UK company as a foreign company in Australia). We’ll cover this below.

Where And How Should You Display Your Company Registration Number?

UK companies are required to disclose certain information under the Companies Act 2006 and related regulations. As a rule of thumb, your company’s name, registered office address, place of registration and CRN should be displayed on key materials.

Make sure your CRN appears in places such as:

• Your website footer and legal pages (e.g., terms, privacy, contact page)
• Business letters, order forms and official correspondence
• Invoices, receipts and other customer-facing documents

This isn’t just best practice – it’s a legal requirement. On the invoicing side, ensure your documents also meet UK invoicing rules. Our guide to UK Invoice Requirements covers the must-have elements, including what to include if you’re VAT-registered.

On your website, your legal notices should be easy to find and up-to-date. If you collect any personal data (for example through contact forms, analytics or e-commerce), you’ll also need a compliant Privacy Policy that explains how you collect, use and protect personal data under the UK GDPR and the Data Protection Act 2018.

Expanding To Australia: How A UK Business Gets An ACN (And Your Other Options)

If you’re planning to expand to Australia, “ACN number” becomes directly relevant. There are a few routes, depending on how you want to operate.

1) Incorporate An Australian Subsidiary (You’ll Get An ACN)

You can set up a new Australian company that’s owned by your UK parent. When you incorporate the Australian entity, ASIC will issue an ACN. You’ll likely also register for an ABN for tax and GST purposes and set up local banking and payroll.

Opting for a subsidiary can be attractive if you want clearer separation of liabilities and local presence. You’ll need to comply with Australian corporate law and reporting obligations, which are separate from UK requirements.

2) Register Your UK Company As A Foreign Company (You’ll Get An ARBN)

Alternatively, you can register your existing UK company as a foreign company in Australia. Instead of an ACN, ASIC issues an ARBN (Australian Registered Body Number). This approach can make sense if you want to trade in Australia without forming a new subsidiary, though you’ll still need to meet local reporting and agent requirements.

3) Use Agents, Distributors Or Licensing (No ACN If You Don’t Establish A Local Entity)

Some UK businesses sell into Australia via distribution or licensing, without setting up locally. You may not need an ACN or ARBN in this scenario, but you’ll want robust contracts in place, clarity on IP licensing, and an understanding of tax implications.

Whichever route you prefer, it’s smart to plan the legal structure, tax, and contracts up front. Our cross-border guide to Registering Or Operating A Foreign Company In Australia outlines the practical steps and common pitfalls so you can choose the right path for growth.

Setting Up Right In The UK: Governance, Documents And Ongoing Compliance

Whether you’re staying UK-only or growing overseas, the foundations you put in place from day one make a big difference. Getting your structure, governance and contracts right doesn’t just keep you compliant – it builds credibility with banks, investors and partners.

Choose And Formalise Your Structure

If you’re operating as a limited company, make sure your constitution (Articles) and internal governance are in good shape. Clear rules make decision-making faster and reduce internal disputes. If you need help tailoring your constitution to your business, we can assist with your Articles Of Association so they reflect how you actually want to run the company.

Protect Your Ownership And Decision-Making

If there are multiple founders or investors, formalise roles, rights and exits. A well-drafted Shareholders Agreement covers voting thresholds, share transfers, vesting, dispute resolution and what happens if someone wants to leave. Without one, even close co-founders can end up in stalemates that stall growth.

Lock In Your Key Trading Terms

Put your commercial relationships on standard, clear terms. Your terms and conditions, service agreements and supplier contracts should set out deliverables, payment terms, IP ownership, limitation of liability and termination rights. If you sell online, your website or platform will need tailored terms, and as noted earlier, a compliant Privacy Policy for data collection.

Hire Confidently And Compliantly

When it’s time to build your team, document employment terms properly. A clear Employment Contract should set expectations around duties, hours, pay, confidentiality, IP ownership, restrictive covenants and notice. Pair it with a sensible staff handbook and keep it aligned with UK employment law.

Stay On Top Of Your Statutory Duties

Company directors must keep registers up to date, file annual accounts and confirmation statements on time, and maintain accurate records. Your CRN is used for all Companies House filings, so keep it handy and ensure your details remain current. If you ever change your registered office, directors or share structure, update the public record promptly.

Put Your Numbers In The Right Places

As mentioned above, your CRN and other identifiers must appear where required by law. This usually includes your website and formal documents like invoices and contracts. Our practical guide on UK Invoice Requirements is a good checklist to make sure you’re covered.

Common Questions About “ACN Number” For UK Businesses

Do I Need An ACN Number To Trade In The UK?

No. If you’re a UK company, your CRN is your primary corporate identifier. You won’t get or use an ACN in the UK.

Is An ACN The Same As A CRN?

They serve similar purposes in their home countries, but they’re not the same. An ACN is Australian; a CRN is UK. If you’re operating in the UK, focus on your CRN and other UK numbers (UTR, VAT, EORI) as needed.

Where Do I Put My CRN?

Display it on your website, business letters, order forms and invoices. It should also be included in formal company documents and filings.

When Would I Ever Need An ACN?

Only if you incorporate in Australia. If you register your UK company to carry on business in Australia without forming a new company, you’ll receive an ARBN instead of an ACN.

How Do I Get A CRN?

Your CRN is issued automatically when you incorporate with Companies House. If you’re ready to set up, our fixed-fee Register A Company service covers the essentials so you can move forward confidently.

Key Takeaways

• “ACN number” is an Australian term. If your business is based in the UK, you won’t have or use an ACN – your core identifier is your Company Registration Number (CRN) from Companies House.
• Keep your identifiers straight: CRN (company identity), UTR (tax), VAT number (if registered), and EORI (imports/exports). Each has a different purpose and disclosure rules.
• Display your CRN where legally required – on your website, business letters, order forms and invoices – and make sure your invoicing meets UK rules.
• If you expand to Australia, you’ll either form a local subsidiary and receive an ACN, or register your UK company as a foreign company and receive an ARBN.
• Set strong legal foundations from day one: solid Articles (constitution), a tailored Shareholders Agreement, clear commercial terms, a compliant Privacy Policy and proper Employment Contracts.
• Staying compliant isn’t just admin – it builds credibility with banks, investors and partners, and helps you scale without unnecessary risk.

If you’d like tailored help with your UK company setup, governance and contracts – or you’re weighing up expansion to Australia – you can reach us on 08081347754 or team@sprintlaw.co.uk for a free, no-obligations chat.