How to Register for Corporation Tax in the UK

/Published:13th March 2025/Updated:2nd May 2025/inRunning a business, Tax
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If you’ve recently set up a limited company in the UK, one of your key responsibilities is registering for Corporation Tax with HMRC. Failure to do so on time can result in fines, so it’s essential to understand the process and deadlines.

In this guide, we’ll cover:

  • What Corporation Tax is and who needs to register
  • The steps to register your business for Corporation Tax
  • Important deadlines and penalties to avoid
  • How to file your Corporation Tax return

What is Corporation Tax and Who Needs to Register?

Corporation Tax is a tax on the profits of limited companies and certain organisations in the UK. Unlike income tax, which individuals pay, businesses must calculate and pay Corporation Tax on their own.

You must register for Corporation Tax if:

  • You’ve formed a limited company (whether trading or not)
  • Your company is making a profit (or expects to)
  • Your company is based in the UK or operates in the UK

Key Fact: Unlike VAT, there is no minimum profit threshold for Corporation Tax. If your company makes a profit, it must pay Corporation Tax.

More info: HMRC: Corporation Tax Overview

When Do You Need to Register for Corporation Tax?

You must register for Corporation Tax within three months of starting trading. “Trading” can include:

  • Selling goods or services
  • Renting out property
  • Advertising or taking on business contracts

If you miss the deadline: HMRC may issue a fine, even if your company hasn’t made a profit yet.

How to Register for Corporation Tax: Step-by-Step

Step 1: Get Your Company’s UTR (Unique Taxpayer Reference)

After forming your company with Companies House, HMRC will send a Unique Taxpayer Reference (UTR) to your registered office address.

  • This 10-digit UTR number is essential for tax registration and filings.
  • If you haven’t received it within a few weeks, contact HMRC.

Find your UTR: Request Your Corporation Tax UTR

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Step 2: Register for Corporation Tax with HMRC

Once you have your UTR, you can register for Corporation Tax online.

  1. Go to HMRC’s registration page: Register for Corporation Tax
  2. Sign in with your Government Gateway account (or create one).
  3. Enter your company details, including:
  • Company name and registration number (from Companies House)
  • UTR (Unique Taxpayer Reference)
  • Business start date (when you began trading)
  • Main business activities
  • Company’s accounting period (usually the same as your financial year)
  • Submit your registration and wait for confirmation from HMRC.

Need help? Contact HMRC at 0300 200 3410.

Step 3: Keep Records and Prepare for Tax Returns

Once registered, your company must:

  • Keep accurate financial records, including income, expenses, and invoices.
  • File an annual Company Tax Return (CT600) and pay Corporation Tax on time.
  • Submit annual accounts to Companies House, even if your company is dormant.

Read more: Guide to Company Tax Returns

How Much Corporation Tax Do You Need to Pay?

The corporation tax year operates from 1st April

Rate2023/242024/252025/262026/272027/28
Main rate25%25%25%25%25%
Small profit rate19%19%19%19%19%
Marginal rate26.5%26.5%26.5%26.5%26.5%

Corporation Tax Thresholds

2023/242024/252025/262026/272027/28
Main rate on profits over£250,000£250,000£250,000£250,000£250,000
Small profits rate up to£50,000£50,000£50,000£50,000£50,000

Penalties for Late Registration or Payment

Failing to register or pay Corporation Tax on time can result in fines.

  • Late registration: HMRC may issue a penalty if you don’t register within 3 months of trading.
  • Late filing of tax returns: You’ll face fines starting at £100 for a one-day delay, increasing if the delay continues.
  • Late payment of Corporation Tax: Interest charges apply on overdue tax payments.

Avoid penalties by filing on time: HMRC Late Filing Penalties

How to Pay Corporation Tax

Once you’ve submitted your Company Tax Return, you must pay Corporation Tax before the deadline.

Payment Methods:

  • Online banking / BACS / CHAPS (usually processed the same day)
  • Direct Debit (takes up to 3 working days)
  • Debit/Credit Card Payments via HMRC’s website

Pay your Corporation Tax here: HMRC Corporation Tax Payment

Final Checklist: Registering for Corporation Tax

Receive your Unique Taxpayer Reference (UTR) from HMRC

  • Register for Corporation Tax within 3 months of trading
  • Keep detailed financial records for tax returns
  • Submit your Company Tax Return (CT600) annually
  • Pay Corporation Tax before the deadline to avoid fines

Need help with tax registration or filing? Contact Accounting Wise for expert small business accounting services.

Conclusion: How to Register for Corporation Tax in the UK

Registering for Corporation Tax is a key responsibility for UK businesses. By completing your registration on time, maintaining accurate records, and filing your tax returns correctly, you can stay compliant with HMRC and avoid costly penalties.

Next Steps:

  1. Ensure your company is registered with Companies House
  2. Register for Corporation Tax within 3 months of trading
  3. Plan ahead for Corporation Tax payments and consider early corporation tax repayments.

Need professional support? Contact Accounting Wise for expert guidance on Corporation Tax, company accounts, and tax planning.

Need help understanding your business finances? Get started today for expert advice on improving your profits.

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