This guide is maintained as a current resource for September 2026 and covers only the laws of England and Wales. Information is for general guidance, not legal advice. Consult a qualified solicitor for advice specific to your situation.
Comprehensive guide to Corporation Tax registration after company incorporation in the UK. Explains when companies must register with HMRC, how to use the Unique Taxpayer Reference (UTR), key deadlines, online enrolment steps, and tax filing and payment obligations for new limited companies.
After a company is incorporated in England and Wales, it must consider its tax obligations promptly. Among these, registering for Corporation Tax with HM Revenue & Customs (HMRC) is a key legal requirement for companies that start trading or otherwise become active. Corporation Tax is the principal tax on a company's profits, and failing to register or file returns on time can lead to penalties and enforcement action. This article explains what Corporation Tax registration involves after incorporation, how liability arises, practical steps to register, deadlines, and related compliance requirements for directors and business owners. The aim is to make the process clear and actionable for non‑experts and solicitors alike, by drawing on authoritative current guidance.
What Is Corporation Tax and When Does It Apply?
Corporation Tax is a UK tax charged on the taxable profits of limited companies and certain organisations such as clubs and societies. It applies to all profits from:
- Trading activities (selling goods or services);
- Investment income (such as interest or property income);
- Chargeable gains (for example, gains arising on the sale of company assets).
A company becomes liable to Corporation Tax from the date it begins to trade or otherwise earns taxable income - this may be the date of incorporation or soon after, depending on when activities commence.
Initial Tax Setup After Incorporation
Notification From Companies House
When a company is incorporated with Companies House, the registrar normally passes the company's details to HMRC. Within a short period - typically within two weeks - HMRC will send a Unique Taxpayer Reference (UTR) for Corporation Tax to the company's registered office. This ten‑digit UTR is used to register for tax online and to file returns.
If the letter from HMRC (sometimes referred to as a CT41G form) does not arrive, directors should contact HMRC or use the online registration service without waiting.
Registering Company Activity
A company must register for Corporation Tax within three months of starting any business activity. “Business activity” is broadly defined and includes buying, selling, renting property, advertising, employing staff, or receiving significant income. If no activity is to be undertaken initially, HMRC should be informed so that the company may be recorded as dormant for Corporation Tax purposes until trading begins.
How to Register for Corporation Tax
Online Registration
The principal route for registration is through HMRC's online services. With the company's UTR, directors or authorised representatives can:
- Create or sign in to the company's Government Gateway account.
- Add the Corporation Tax service to the account.
- Provide key details including the date the company started business and the accounting period end date (the date up to which accounts will be prepared).
After enrolling, HMRC will send an activation code to the registered office address by post. This must be used to activate the Corporation Tax service in the online account.
Alternative Registration Methods
If online registration is not possible, companies can use a paper form (such as CT41G if issued by HMRC) or contact HMRC by letter with the company name, UTR, business start date and accounting period end date.
Key Information Required for Registration
When registering for Corporation Tax, HMRC generally asks for:
- Company name and registered number;
- Date the company became active and start of its accounting period;
- Company's registered office address;
- Nature of business activities (often through Standard Industrial Classification codes);
- Details of directors and contact information;
- Accounting period end date.
Accurate completion of these details ensures that HMRC records are correctly set up for future tax returns and payments.
Deadlines and Penalties
Registration Deadline
A company must register for Corporation Tax within three months of commencing business activity. Late registration can lead to penalties and interest, especially where tax ultimately remains unpaid or returns are filed late.
Filing and Payment Obligations After Registration
Once registered, a company must:
- Prepare and file annual Company Tax Returns (CT600) with HMRC even if it makes a loss or owes no tax. The return is typically due 12 months after the end of the accounting period.
- Pay Corporation Tax, normally due nine months and one day after the end of the accounting period.
- File statutory accounts with Companies House, which help determine taxable profits.
Failing to meet these obligations can attract a range of penalties, including financial charges and compliance notices.
Dormant Companies and Corporation Tax
If a company is not trading (no sales, purchases, interest, or other income), it may be classified as dormant for Corporation Tax purposes. In this case, companies should notify HMRC, after which HMRC will usually not require CT600 returns until the company becomes active. However, separate statutory accounts may still be required for Companies House.
Common Challenges and Practical Tips
Missing UTR or Activation Letters
If the UTR or activation code is not received within a reasonable time (typically 14–21 days after incorporation), it is advisable to contact HMRC promptly and register online using the GOV.UK service, rather than waiting for post.
Choosing an Accounting Period
Selecting an accounting period end date is important because it affects filing deadlines and tax due dates. Companies often choose a date that aligns with business cycles or matches the financial year, but this decision should be made with care, possibly with professional accounting advice.
Maintaining Accurate Records
Accurate bookkeeping from the outset makes tax return preparation and compliance easier and reduces the risk of penalties from HMRC. Directors are ultimately responsible for ensuring that the company meets its statutory tax obligations.
Summary
After incorporation, a company must register for Corporation Tax with HMRC if it begins trading or otherwise undertakes taxable activities. Directors should expect to receive a Unique Taxpayer Reference (UTR) soon after incorporation, which they need to use to register online or via alternative methods. Registration must be completed within three months of starting business activity. Once registered, a company must file annual tax returns, pay any tax due by statutory deadlines and maintain accurate records to support filings. Informing HMRC promptly whether the company is active or dormant helps prevent unnecessary tax returns and compliance issues. Directors should plan their accounting period, prepare for ongoing HMRC filings and consider professional tax support if needed.
