Starting a company in the UK is a significant first step in your business journey. At the heart of that process is Form IN01, the official application you’ll need to complete and submit to Companies House to register your company.
Whether you’re forming your first business, establishing a UK presence, or helping a client, understanding this form and the information that goes into it is crucial. In this guide, we’ll explain exactly what the Form IN01 does, who needs to use it, how to fill it in, and why working with a formation agent simplifies the whole experience.
Key takeaways
- Form IN01 is a central part of the application for registering a UK company.
- Using a formation agent removes the guesswork. They’ll handle the form for you, arrange the supporting documentation, and ensure submission is completed correctly.
- Submitting an incorrect IN01 can sometimes require more complex legal corrections, so it’s essential to enter the information correctly the first time.
What is the Form IN01, and why is it so important?
The Companies House IN01 Form is a legal document that’s a vital part of the process for incorporating the following types of UK companies:
- Private companies limited by shares
- Private companies limited by guarantee
- Public limited companies
- Private unlimited companies
The full name of the form is the “IN01 – Application to register a company” and it represents your first big step in setting up your company and bringing your vision to life.
- A to Z of company formation terms
- What happens after I submit my company formation application?
- How to register a company in 4 simple steps with 1st Formations
For this article, we’ll concentrate on completing the Form IN01 for a private company limited by shares.
What does the Form IN01 actually do?
The Form IN01 (also referred to as the IN01 Form) is the main part of a company registration application. It’s where you enter key information about your future company – for example, your business’ name, its purpose, who runs it, who owns it, and other details.
Who needs to complete the Form IN01?
Anyone forming a UK limited company must complete Form IN01 and submit it to Companies House, the registrar of UK companies. Without it, the company cannot be formed.
Incorporating online vs post – what is right for you?
For most businesses, online registration is faster, cheaper, and far less likely to be rejected, which is why it’s now used by more than 99% UK companies. Typically, a formation agent carries this out. Electronic formations are preferred over postal ones in almost all cases due to fewer errors, faster one-day processing, and lower costs starting from just £100:
| Method | Companies House fee | Usual approval time | Same-day service available? | Rejection rate |
| Online | £100 | Usually 1 working day | Yes | Less than 10% |
| Post | £124 | Usually 8 to 10 working days | No | More than 50% |
Overall, the general recommendation is to always register online. Better still, a formation agent, like 1st Formations, can provide valuable guidance throughout the process and ensure everything is done correctly.
Unsure which formation agent to use? Read our comparison of the Top 11 UK company formation agents 2025 to make an informed decision.
How do I complete the Form IN01?
There are a few ways to complete Form IN01 electronically. As mentioned earlier, the simplest way is through a company formation agent. As you start your business journey, you’ll find that many company formation agents have user-friendly websites and use step-by-step forms to gather the information, making it a smooth and stress-free experience. Plus, the formation agent uses your information to complete and submit your Form IN01, so you don’t have to interpret all 38+ pages of legal documents yourself.
A company formation agent will also handle supporting documents, submit everything directly to Companies House, and offer helpful add-ons like address services and other compliance services, which you’ll most likely need.
If you’re filing Form IN01 by post, you’ll need to download it from Companies House, fill out the PDF, print it, and then post it to Companies House with any required supporting documents and a cheque with the £124 fee.
What information do I need to enter on the Form IN01?
In line with Part 2 of the Companies Act 2006, you need to provide some key company information on the Form IN01. Here’s what you’ll need to include:
- The company name – what you will call your business
- The type of company – for instance, a private company limited by shares
- The registered office address – the official UK address of the company
- The registered email address – the email address used for receiving government reminders and notices
- Whether the company will use the model articles of association
- Details of each director – these are the people who run the company. Their details include their full name, date of birth, home address, and service address
- Details of each company secretary (optional)
- Details of each shareholder – these are the owners of the company. Details required include their name, address, and how many shares they will each hold
- Details of the share capital – things like classes, the nominal value, and the rights attached to the shares
- Details of the people with significant control
- Statement of compliance – this confirms the application complies with the law
- Lawful purpose statement – this confirms the company is being formed for lawful purposes.
Do I need to provide any other documents with the Form IN01?
If you’re setting up with a formation agent, they’ll usually handle all the supporting paperwork. If you’re registering independently, you must provide a memorandum of association (unless you’re applying online – Companies House generates this automatically).
Unless you choose to use the model articles, you’ll also need to include your articles of association (the main part of the company’s constitution).
What happens after I send the Form IN01 to Companies House?
Once your Form IN01 and supporting documents are submitted, Companies House will review and process your application. If everything’s in place, you’ll receive your official Certificate of Incorporation. This proves that your company legally exists and is ready to start trading.
What happens if I make a mistake on the Form IN01?
Mistakes happen – even on formal documents like the IN0 Form. This is where using a formation agent helps reduce this risk of error, as they guide you through the process and ensure all required information is submitted correctly.
Resolving an error depends on its type. Simple admin mistakes, like missing a field, usually lead to rejection – this just needs to be corrected and resubmitted. Bigger errors, such as allocating shares or incorrectly naming the company, may require more complex procedures to fix.
Below are some of the most common IN01 mistakes and how to correct them after registration.
| Mistake | How to correct |
| Wrong registered office address | Decide on the correct address, then file Form AD01 with Companies House to update the official record. |
| A person not being appointed as a director | The person will need to be formally appointed. Usually, this means the individual providing written consent, the board approving, and then notifying Companies House. |
| Spelling mistake in the company name | For most companies, the shareholders must pass a special resolution approving the new name, then file Form NM01 with Companies House to update it. |
| Not enough shares given to the shareholder(s) | This normally requires an issue of shares to add more shares to the company and the relevant shareholder(s). This requires shareholder application, board/shareholder approval, and updates to records and Companies House. |
| Too many shares given to the shareholder(s) | This is a little more complicated. Usually, a reduction of capital, share buyback, transfer, or share consolidation will be required (depending on the situation). |
Curious to find out why company formations are rejected? Discover the top 15 reasons for rejections.
Get your company application right the first time
Form IN01 plays a key role in the company formation process in the UK. It captures essential details about your business, from its name and structure to its directors and registered office address. Companies House can’t approve your application without a completed Form IN01.
That’s why it’s strongly recommended that you use a professional formation agent to complete and submit the IN01 on your behalf. This not only saves time and reduces errors, but it also gives you peace of mind that your company has been set up properly from day one. Plus, you can rest assured that extra services help keep your company safe and compliant while also protecting your privacy.
Thinking about setting up your company? If you’d rather skip the paperwork and focus on getting started, 1st Formations can help. We’ll make sure your details are submitted accurately, including for Form IN01, so your company can be registered quickly and correctly, often within one working day.
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