What is a CT600 return?

A CT600 is the official Company Tax Return form that UK limited companies must file with HM Revenue & Customs (HMRC). It is a legal requirement used to report your company's income, calculate Corporation Tax owed, and detail any capital allowances or reliefs you are claiming.

Who needs to file it?

Every active UK limited company must file a CT600 annually, even if they have not made a profit or have no Corporation Tax to pay. If HMRC has issued a notice to deliver a Company Tax Return, you are legally obligated to complete and submit it.

CT600 vs. Annual Accounts

While both are required annually, they serve different purposes. Annual accounts are filed with Companies House to make your financial performance public. The CT600 is filed with HMRC specifically to calculate your tax liability. Both are typically prepared at the same time and require similar financial data.

Filing Timeline

There are two crucial deadlines to remember: you must pay your Corporation Tax within 9 months and 1 day after your accounting period ends. However, you have 12 months from the end of your accounting period to actually file the CT600 return. Filing early gives you clarity on exactly how much you need to pay.

What happens if you don't file?

Failing to file your CT600 on time will result in automatic penalties starting at £100. If you are more than 3 months late, another £100 is added. If you consistently fail to file, HMRC will estimate your tax bill (a 'determination') which cannot be appealed, and Companies House may begin steps to strike your company off the register.

Common Misconceptions

A common mistake is believing that if your company didn't trade or didn't make a profit, you don't need to file. Unless HMRC has explicitly agreed to treat your company as dormant for tax purposes, you must still file a 'nil' return.

How WeFile helps

WeFile simplifies this process by providing an intuitive, wizard-driven interface. We automatically calculate your Corporation Tax based on your profit and loss inputs, eliminating the need for complex manual calculations and ensuring accurate submissions directly to HMRC.