What is a Company Tax Return?

If your company or organisation is liable for Corporation Tax you'll have to file a Company Tax Return for each accounting period. Generally, you must file a return even if your company or organisation hasn't made any taxable profits. This guide explains what a Company Tax Return is, how you will be required to provide your return information to HMRC and provides links to more detailed guidance, should you need it.

On this page:

What's included in a Company Tax Return
Attaching accounts and computations to your online return
More useful links

What's included in a Company Tax Return

A complete Company Tax Return is typically made up of a number of items:

An online return form CT600 and your declaration at the end of it.
Company accounts (sometimes known as statutory accounts) - these are the accounts your limited company must prepare for its members under the Companies Act - including director’s reports and auditor’s reports. If your company chooses to file abbreviated accounts at Companies House, you must still file full statutory accounts as part of your Company Tax Return. If your organisation is not incorporated at Companies House the accounts required are those your organisation must prepare under its constitution.
Separate computations and/or calculations - for example, if you fill in Boxes 3, 16, 17, 43 to 62, 64, 105 to 121 or 131 of the CT600, you need to include a computation as part of your online return showing how you worked out those figures.

You may also need to submit additional items as part of your return. These will depend on the particular circumstances of your company or organisation. These include:

Supplementary pages, for example:
- Loans to Participators by Close Companies - directors' loans (form CT600A)
- Charities and Community Amateur Sports Clubs (CASCs) (form CT600E)
- Tonnage Tax (form CT600F)
Any other relevant claims, elections, reports or statements, for example:
- A claim to carry back loss relief under S37 CTA 2010
- An election for short-life asset treatment under S83 CAA 2001

Top

Attaching accounts and computations to your return

With some exceptions, the accounts and computations attached to a return must be in a set format - Inline eXtensible Business Reporting Language (iXBRL). iXBRL is an IT standard designed specifically for business financial reporting - not just tax filing. But don't worry, you don't have to be an IT expert to file online, your software will do most of the work for you.

Companies

All companies that are required to file a return form CT600 online must file their accounts and computations in iXBRL.

Unincorporated charities, clubs and societies

All unincorporated charities, clubs and societies that are required to file a return form CT600 must file their computations iXBRL. However, they can choose to file their accounts in either iXBRL or Portable Document Format (PDF).

Additional enclosures or attachments to your online return

You can only include one iXBRL accounts file as part of your online Company Tax Return. Any additional accounts forming part of the return must be attached as PDF files.

If you have any other information that you need to include as part of your Company Tax Return - for example, claims or elections, reports or statements - you can attach these to your online return as a PDF.

The maximum combined size for attachments when using the free HMRC software is 5MB.

If you're using commercial software and will be attaching files, please check with your supplier that the product is compatible with the Corporation Tax online service.

More about filiing accounts in iXBRL or PDF format (PDF 33K)

Top