How to Change Your SIC Code at Companies House

If your company has changed what it does, your Standard Industrial Classification (SIC) code may need to change too. A SIC code is the five-digit code Companies House uses to describe a company's principal business activities. It is recorded on the public register and helps identify the type of economic activity a company carries out. Companies House currently provides a condensed list of SIC codes for companies to use when filing.

Changing a SIC code is relatively straightforward, but it is important to choose a code that genuinely reflects your company's current activities. Since Companies House now has stronger powers to challenge information that appears incorrect, inconsistent or misleading, treating the SIC code as a formality can create unnecessary problems. This guide explains when you should change your SIC code, how to choose the right one, how to update it with Companies House and what the change means for your company's records.

What Is a SIC Code?

A Standard Industrial Classification code, commonly called a SIC code, is a numerical classification used to describe the economic activity of a business. For example, a company operating as a restaurant, software developer, property management business or advertising agency will generally use a different SIC code to describe its activities.

Companies House uses a condensed version of the wider SIC classification maintained by the Office for National Statistics (ONS). Importantly, when filing with Companies House, you should use a code from the Companies House condensed list; using an inappropriate code can result in a filing being rejected. A company can select up to four SIC codes if it carries out several different business activities. At least one appropriate code must be provided.

Why does your SIC code matter?

It may seem like an administrative detail, but the code provides a public description of what your company does. For founders, lenders, investors, suppliers and potential customers, the information on the Companies House register can form part of the picture they use to understand a company.

An inaccurate code can therefore become more than a minor paperwork issue. Companies House has specifically warned that discrepancies between a company's activities and its SIC code can potentially affect filing processes, lender relationships or funding eligibility.

When Should You Change Your SIC Code?

You should consider changing your SIC code when your company's actual business activities have materially changed. For example:

• A marketing agency begins operating primarily as a software company.
• A consultancy launches a separate training business that becomes a major part of its operations.
• A retail company moves into wholesale distribution.
• A technology business changes from providing consultancy services to developing and licensing software.
• A property company changes the nature of its activities.
• A previously dormant company begins trading.
• A company expands into a different sector and its existing code no longer accurately describes the business.

The key question is simple: Does the SIC code currently recorded at Companies House accurately describe what the company actually does? If the answer is no, it is worth reviewing the code. Companies House has emphasised that active companies should not use dormant or non-trading classifications simply because those codes were selected previously.

How to Choose the Right SIC Code

Choosing the correct code is often more difficult than submitting the change. Companies House does not expect you to write your own description and create a new code. You need to select from its available condensed SIC list.

1. Start with what the company actually does

Don't choose a code simply because it sounds attractive or because it is commonly used in your industry. Consider the company's real economic activities. For example, suppose a business was incorporated as a general consultancy but now earns most of its revenue from developing and licensing software. Its original consultancy-related SIC code may no longer provide an accurate description of the business.

2. Consider your main activities

If the company performs several activities, identify the ones that are genuinely significant. Companies House allows up to four SIC codes, which can be useful for businesses with multiple lines of activity. For example, a company might provide:

1. Management consultancy
2. Professional training
3. Business support services
4. Software development

The appropriate combination will depend on what the company actually does rather than what the founder intends to do in the future.

3. Search the official SIC list

Companies House provides an online condensed SIC code list that can be searched by business activity. Only codes from this list should be used when filing with Companies House.

4. Look at similar companies carefully

Companies House has suggested that searching for similar companies can help when you are unsure how to classify your activities. However, don't simply copy another company's SIC code. Two businesses in the same broad industry can have very different activities. A technology company that develops software, for example, may require a different classification from a company that provides IT consultancy or operates an online marketplace.

How to Change Your SIC Code at Companies House

The usual way to update your SIC code is through your company's confirmation statement. The confirmation statement is the annual filing used to confirm that the information Companies House holds about the company is up to date. Companies House specifically allows changes to the company's SIC code to be included when filing the confirmation statement.

Step 1: Check your current SIC code

Before changing anything, search for your company on the Companies House register. Review the company's current SIC code and compare it with its actual activities. This gives you a useful starting point and helps you determine whether a change is actually necessary.

Step 2: Identify the appropriate replacement code

Use the official Companies House condensed SIC list to find the code that best describes your company's current business activity. If your company carries out multiple activities, you can select up to four relevant codes.

Step 3: Prepare your confirmation statement

Your SIC code is updated through the confirmation statement process. Companies House states that the confirmation statement can be used to update information including:

• SIC codes
• Statement of capital
• Shareholder information
• Certain share-related information

Other changes, such as changes involving directors or PSCs, may need to be dealt with separately before the confirmation statement is submitted.

Step 4: File online

For eligible companies, the Companies House online confirmation statement service can be used to submit the filing. The current online service has eligibility requirements. For example, it is available to certain private companies limited by shares with one shareholder, between one and five officers, five or fewer PSCs, and the required director identity verification information. Companies that do not meet the criteria may need to use WebFiling instead. You will generally need your company number and the appropriate Companies House login/authentication credentials.

Step 5: Pay the applicable filing fee

The current Companies House online confirmation statement fee is £50. A paper confirmation statement costs £110. The online filing is therefore normally the more convenient and cheaper option.Companies House also states that the annual confirmation statement fee is paid once within the relevant 12-month payment period; additional confirmation statements within the same payment year do not attract another annual fee.

Do You Have to Wait Until Your Annual Confirmation Statement?

Not necessarily. A company does not have to wait for the end of its financial year simply because its business activity has changed. A confirmation statement can be filed when appropriate to update information, including the SIC code. This can be particularly useful where the change in business activity is significant and you want the public Companies House record to reflect the company's current position sooner rather than leaving an obviously outdated classification on the register.

The important point is that the confirmation statement is still an annual requirement. Every company, including dormant and non-trading companies, must file one at least once every year.

Can You Change Your SIC Code More Than Once?

Yes. A company's activities can evolve over time, so its SIC classification may need to change accordingly. For example, imagine a founder starts GreenBridge Consulting Ltd as a management consultancy. Two years later, the business develops proprietary software and begins earning most of its revenue from software licensing.

The company shouldn't necessarily continue using its original consultancy classification indefinitely simply because that was its activity at incorporation. If the business changes again later, the SIC codes can be reviewed again. The objective is not to find a code that describes everything the founders might eventually do. It is to maintain a reasonably accurate description of the company's current business activities.

What If Your Company Has Multiple Business Activities?

This is common, particularly among startups and growing companies. Consider a business that provides:

• Business consultancy
• Professional training
• Online courses
• Digital products

Trying to force all four activities into a single classification may not give a complete picture. Companies House allows up to four SIC codes, so multiple codes may be appropriate where the business genuinely operates across several activities.

However, more codes are not automatically better. Adding unrelated codes simply to make the company appear broader can make the company's public record less meaningful. A useful approach is to ask: What activities actually generate the company's business today? Then select codes that accurately represent those activities.

What Happens If Your SIC Code Is Wrong?

An incorrect SIC code does not automatically mean your company has committed a serious offence. However, it is information on the public register, and Companies House has strengthened its powers to scrutinise information submitted to the register.

Under changes introduced through the Economic Crime and Corporate Transparency Act, Companies House can challenge, reject or remove information that appears incorrect, inconsistent or misleading.

There can also be practical consequences. A lender reviewing your company may notice that the registered business activity doesn't appear consistent with the business you are seeking finance for. Similarly, an investor or commercial partner may question why your public company classification differs from your pitch deck, website or accounts. That does not mean a SIC code determines whether you can legally perform an activity. It is primarily a classification of the company's economic activity. But accuracy matters.

Does Changing Your SIC Code Change Your Company?

No. Changing a SIC code does not create a new company. Your:

• Company number
• Legal entity
• Incorporation date
• Existing contracts
• Shareholding structure
• Directors

do not change simply because you update the company's business classification. It is an update to the company's registered information. There may, however, be separate regulatory or tax implications depending on what the company's new activity involves. For example, moving into financial services, healthcare, regulated transport, childcare or another regulated sector may require additional permissions or registrations. Changing the SIC code itself does not provide those permissions.

SIC Code vs Your Company Name and Objects

These are often confused. Your company name identifies the legal entity. Your SIC code classifies its economic activities on the Companies House register. Your company's constitutional documents and business arrangements can contain broader information about what the company is permitted to do.

A change in SIC code therefore does not necessarily mean you need to change your company name or rewrite your entire business structure. For founders, the practical lesson is to treat these as separate questions:

What is the company called?

What does the company actually do?

What activities are reflected in its constitutional and commercial arrangements?

What regulatory permissions, if any, are required?

What About Tax and HMRC?

Changing your SIC code at Companies House does not automatically mean your tax affairs have been updated in every relevant respect. Companies House and HMRC are separate government bodies with different responsibilities. If your business has changed substantially, consider whether the change affects:

• Corporation Tax
• VAT
• PAYE
• Industry-specific tax treatment
• Business rates
• Accounting records
• Regulatory registrations

The SIC update should therefore be viewed as one part of keeping your overall business records accurate, rather than as a substitute for reviewing your tax and regulatory obligations. For significant changes in business activity, professional accounting or legal advice may be appropriate.

Do Global Founders Need to Pay Special Attention?

Yes. International founders often establish a UK limited company for consulting, technology, e-commerce, professional services or other activities while managing operations from outside the UK. For these businesses, the Companies House record can become particularly important because prospective banks, payment providers, investors, suppliers and commercial partners may use the public register when carrying out due diligence.

If the company's website says it is a software development business but the Companies House record still describes it using an unrelated or obsolete classification, that inconsistency can invite questions. For overseas founders using a UK company formation and management platform such as IncorpUK, keeping the SIC classification aligned with the company's actual activities should be treated as part of ongoing company administration—not merely something to think about during incorporation.

A Practical SIC Code Review Checklist

Before filing a new SIC code, work through this checklist:

Business activity

• What does the company actually do today?
• Has its main source of revenue changed?
• Has it entered a new industry?

SIC selection

• Have you checked the official Companies House condensed SIC list?
• Does the selected code accurately describe the activity?
• Are additional codes genuinely necessary?

Compliance

• Is the company actively trading, dormant or non-trading?
• Are you using an appropriate classification?
• Does the company's public record remain consistent with its other business information?

Filing

• Is your confirmation statement due?
• Does your company qualify for the relevant online filing service?
• Do you have the necessary authentication and account details?
• Have you budgeted for the applicable filing fee?

Wider implications

• Does the new business activity require a licence or regulatory approval?
• Does your accountant need to review the change?
• Could the new activity affect VAT, Corporation Tax or other obligations?
• Do your bank, insurers or commercial contracts need updating?

This checklist can prevent a surprisingly common mistake: changing the SIC code while overlooking the wider consequences of changing the business itself.

Frequently Asked Questions

Can I change my SIC code online?

Yes. A company's SIC code can be updated through the confirmation statement filing process. Eligible companies can use the online Companies House service, while others may need to use WebFiling.

Does changing a SIC code cost money?

The SIC change is made as part of the confirmation statement. The current online confirmation statement fee is £50, while the paper filing fee is £110.

Can a company have more than one SIC code?

Yes. Companies House allows a company to select up to four SIC codes where it carries out several relevant business activities.

Can I change my SIC code without changing my company name?

Yes. A SIC code describes the company's business activity; it does not determine the company's legal name.

How do I find my company's current SIC code?

Search for your company using the Companies House company information service and review the company's registered information. You can then compare the existing classification with the official SIC list.

Can I use any SIC code I find online?

No. Companies House says you should use codes from its condensed SIC list when filing. Using a code outside the applicable list can result in rejection.

Should I change my SIC code if my company starts a new business?

If the new activity means the existing SIC code no longer accurately reflects what the company does, you should review and potentially update the code.

Can my SIC code affect business funding?

Potentially. Companies House has noted that an inaccurate SIC classification can affect relationships with lenders or eligibility for certain funding.

Does a SIC code give me permission to operate a regulated business?

No. A SIC code classifies your economic activity; it does not itself grant a licence or regulatory authorisation. If your new activity is regulated, check the requirements of the relevant regulator.

Final Thoughts

Changing a SIC code is a relatively simple Companies House task, but the decision behind the change deserves more attention than the filing itself. The right approach is to start with the company's real commercial activity, identify the closest appropriate classification in the official Companies House list, and update the code through the confirmation statement process.

For a growing company, this is more than housekeeping. Your Companies House record is part of your company's public identity, and accuracy increasingly matters as Companies House strengthens its scrutiny of information on the register. If your business has evolved, don't let an outdated SIC code tell the wrong story. Review what the company actually does, select the most appropriate classification, update the register and then check whether the underlying change creates any separate tax, licensing, banking or regulatory obligations.

For founders, particularly those building or managing UK companies from overseas keeping these details aligned is a small administrative task that can make the business look considerably more credible and well managed.