By
August 8, 2026
Learn how to register your UK company for Corporation Tax, meet HMRC requirements, understand key deadlines, and stay compliant after company formation.
Have you recently registered a company in the UK? One of the next important steps is understanding whether and when you need to register your business for UK Corporation Tax.
Forming a limited company with Companies House is only the beginning. Once your company starts doing business, you will normally need to notify HM Revenue & Customs (HMRC) and ensure that your company is correctly set up for Corporation Tax.
In this guide, we explain how UK Corporation Tax registration works, when you need to register, what information you need and the key deadlines new UK company owners should know.
Corporation Tax is a tax that UK companies may pay on their taxable profits.
These profits can come from activities including:
If you have recently established a UK limited company and intend to start trading, Corporation Tax should be an important part of your post-company-formation checklist.
Most UK limited companies need to deal with Corporation Tax once they become active and start doing business.
However, there is an important distinction between forming a company and starting to trade.
Your company may be registered at Companies House but remain dormant if it has not started conducting business.
Once the company becomes active, you generally need to notify HMRC that it is liable for Corporation Tax.
A company generally needs to tell HMRC that it is liable for Corporation Tax within three months of starting to do business.
This makes the date your company becomes active particularly important.
For example, you might incorporate your UK company on 1 January but only start doing business on 1 March. These dates should not automatically be treated as the same.
Keeping accurate records from the beginning can help you establish when your company's business activities started.
Corporation Tax registration can generally be handled online through HMRC.
Before starting, make sure you have your company details available.
You may need information including:
Once HMRC has the necessary information, your company can be recognised as active for Corporation Tax purposes.
After setting up a UK company, HMRC normally issues the company with a 10-digit Unique Taxpayer Reference, commonly known as a UTR.
Your UTR is different from your Companies House registration number.
It is an important tax reference and may be required when:
Keep your UTR and other company documents securely stored.
Corporation Tax is only one consideration when getting a new UK company operational.
New business owners should typically consider:
Taking care of these requirements early can make running your UK company significantly easier.
New company owners should understand that there can be different deadlines for paying Corporation Tax and submitting a Company Tax Return.
For many companies, Corporation Tax is generally due 9 months and 1 day after the end of the relevant accounting period.
The Company Tax Return is generally due 12 months after the end of the accounting period it covers.
Companies House accounts can have a different deadline again.
Do not assume that all three deadlines fall on the same date.
You may have formed a company but decided not to start trading immediately.
In this situation, your company may be considered dormant for Corporation Tax purposes.
You may need to tell HMRC that the company is dormant. When the business eventually starts trading, you should ensure that HMRC is informed and that the appropriate Corporation Tax requirements are followed.
This is particularly relevant for entrepreneurs who register a company several months before launching their business.
UK companies can have directors and shareholders who live outside the United Kingdom.
If you are an international entrepreneur who has established a UK company, however, you should not assume that living overseas removes the company's UK tax obligations.
Your UK company may still have Corporation Tax, accounting and reporting requirements.
You may also have tax obligations in the country where you live or operate your business.
For international company owners, obtaining appropriate professional tax advice can help determine how UK and overseas tax rules apply to the business.
Many new UK companies operate entirely online.
For example, your company might run:
Operating online or receiving payments from overseas customers does not automatically remove UK company tax responsibilities.
Businesses operating internationally should maintain clear records of their transactions and seek professional advice where cross-border tax issues arise.
Once your company is ready to trade, separating company transactions from personal finances can make bookkeeping and financial management much easier.
Depending on the business and provider, a company may be able to open a business account that allows it to receive, convert and send payments in currencies such as GBP, EUR and USD.
This can be particularly useful for UK companies working with international customers, suppliers or online platforms.
When comparing business account providers, consider:
The right solution will depend on your company's business model, location, ownership structure and expected transaction activity.
One of the biggest mistakes new business owners make is assuming that registering a company means everything is automatically set up.
After incorporation, remember to consider your company's tax, accounting, banking and regulatory responsibilities.
Common mistakes include:
If you have just formed a UK company, your next steps should include:
✓ Confirm your company's trading status
Determine whether the company is active or dormant.
✓ Locate your company UTR
Keep the HMRC-issued reference securely stored.
✓ Register for Corporation Tax when required
Make sure HMRC is informed when your company becomes active.
✓ Set up business banking
Arrange a suitable account for receiving and making company payments.
✓ Start bookkeeping immediately
Keep records of all company income, expenses and transactions.
✓ Check VAT requirements
Determine whether VAT registration applies to your business.
✓ Review PAYE requirements
Consider whether payroll registration is necessary.
✓ Record important deadlines
Track Corporation Tax, Companies House and other filing dates.
Setting up a UK limited company can provide a professional structure for doing business in the UK and internationally, but incorporation is only the first step.
Once your company starts doing business, you should make sure that Corporation Tax registration, accounting, banking and ongoing compliance requirements are properly addressed.
Getting these foundations in place early allows you to concentrate on what matters most: building, operating and growing your business.
