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Register for Corporation Tax

When and how to register your company for Corporation Tax with HMRC.

Registering your company for Corporation Tax is a key responsibility after incorporation. Ensuring this is done correctly and on time will help you avoid penalties and keep your business compliant.

When to Register for Corporation Tax

You must register your company for Corporation Tax with HMRC within 3 months of starting business activities.

“Starting business activities” can include:

  • Trading or selling goods/services

  • Buying or selling assets

  • Earning interest

  • Hiring employees

  • Advertising or promoting your business

Even if your company is not yet making a profit, you may still need to register once business activity begins. 

What If Your Company Is Dormant?

If your company is not trading and has no significant accounting transactions, it may be considered dormant. In this case, you should inform HMRC that your company is dormant, and you may not need to register for Corporation Tax until trading begins. This can be done online here.

How to Register for Corporation Tax

You can register online via HMRC. Before you begin, make sure you have the following information ready:

  • Your company’s Unique Taxpayer Reference (UTR)

  • Company registration number (find this by searching your company name here)

  • Date your company started trading

  • Your accounting period dates

  • Details of your business activities

Once registered, HMRC will confirm your Corporation Tax obligations and deadlines.

After You Register

Once your company is registered for Corporation Tax, you will need to:

  • Keep accurate accounting records

  • File a Company Tax Return (CT600) each year

  • Pay any Corporation Tax due on time

Key Deadlines to Remember

  • Registration deadline: Within 3 months of starting business activity

  • Corporation Tax payment: 9 months and 1 day after your accounting period ends

  • Tax return filing: 12 months after your accounting period ends

Need Help?

Registering for Corporation Tax can be straightforward, but it’s important to get it right. If you’re unsure about your obligations or need assistance, professional support from an accountant can help ensure everything is completed accurately and on time.