Guidance overview: How to complete a Company Tax Return

Use this guide to help you complete form CT600 (2021) version 3.

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How to complete a Company Tax Return

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Details

This guide will help you complete the Company Tax Return CT600 (2021) version 3.

You should read all the general notes and use the box-by-box advice when you’re completing the form.

Published 7 April 2015
Last updated 15 November 2021 + show all updates
  1. Section '155 Trading profits' has been updated with information on what to do if you received a taxable coronavirus support grant.

  2. The guide to help you complete form CT600 (2021) version 3 has been updated.

  3. New CT600 guide (2021) version 3 has been added.

  4. Updated for 2021.

  5. The guidance has been updated with information about Capital Allowances and the Non-Resident Landlords scheme to make things clearer for software developers and their customers.

  6. New CT600 guide (2020) version 3 has been added.

  7. Guide changed to link to the new Finance Act where needed.

  8. New CT600 guide (2019) version 3 added.

  9. The guidance has been updated with information about restitution tax for boxes 170 and K20.

  10. The guidance for Loss Reform and Corporate Interest Restriction (CIR) to help companies file their Company Tax Return has been updated.

  11. The guidance has been updated with information relating to the number of 51% companies and clarification of the supplementary charge rate.

  12. The PDF has been updated to correct parts of the CT600 guide (2018).

  13. The guide has been updated to clarify parts of the CT600 form.

  14. New CT600 guide (2018) version 3 added.

  15. CT600 guide (2017) has been updated to include the new loss reform rules that apply for periods ending on or after 1 April 2017.

  16. New CT600 guide (2017) version 3 added.

  17. CT600_Guide_V3. replaced by CT600_Guide _V0.1

  18. First published.