Original document : https://www.gov.uk/guidance/the-company-tax-return-guide

Change description : 2025-04-01 08:13:00: Guidance to complete boxes 541, 614, 658, 663, 886 and 943 has been added. Guidance to complete boxes 540, 545, 625, 650, 657, 659, 665 and 885 has been updated. [Guidance and regulation]

Showing diff : 2024-12-23 10:56:50.237934343 +00:00..2025-04-01 07:13:14.237130891 +00:00

Guidance

Completing your Company Tax Return

How to complete your CT600 Company Tax Return form for Corporation Tax and what information you need to include.

Update history

2025-04-01 08:13
Guidance to complete boxes 541, 614, 658, 663, 886 and 943 has been added. Guidance to complete boxes 540, 545, 625, 650, 657, 659, 665 and 885 has been updated.

2024-12-23 10:56
Information for box 625 has been updated. If your accounting period ends on or after 1 April 2023, you must complete box 326 instead. You must leave this box blank if your company has no related 51% group companies.

2024-12-19 10:38
A link has been updated in section 659 of the section ‘Research and Development (R&D) or creatives enhanced expenditure and tax reliefs’, to new guidance on what R&D costs you can claim.

2024-10-15 12:41
We have clarified how to calculate claims relating to Audio-Visual Expenditure Credit and Video Games Expenditure Credit in box 885 step 6.

2024-09-10 10:50
Information for boxes 326, 327 and 328, 625, 630 and 631 have been updated to confirm when you must complete the box and what you should enter in the box depending on how you pay your instalments and your business accounting periods.

2024-08-06 13:18
Guidance to complete box 540 has been updated to explain that it should be the total amount of any creatives tax credits that the company is claiming for the period. Information has been added covering what to include in this box for claims to the Audio-Visual Expenditure Credit and the Video Games Expenditure Credit.

2024-06-26 11:20
The information for boxes 630 and 631 has been updated to include what figure to enter if there is no previous accounting period.

2024-06-19 14:22
The listed conditions on the energy technology list website for designated environmentally friendly machinery and plant has been updated. Information has been added to the small profit rate or marginal relief entitlement to support completion of the tax return.

2024-06-18 15:54
The information for box 185 has been updated to show when you need to provide form NRL6.

2024-05-10 10:50
Information has been added covering who can claim Marginal Relief and to support the completion of the CT600.

2024-05-03 16:02
Guidance on how to complete box 4 ‘Type of company’ updated to include that you should enter 0, if the company is in the first year of liquidation, unless one of the other company types apply. Enter 3, if the company is in the second or later year of liquidation.

2024-04-06 00:15
The page has been updated to include changes for the tax year 2024 to 2025.

2024-03-15 15:13
Section 657 Additional information form has been updated to include that the form must be submitted by 11:59pm on the day the Company Tax Return is submitted.

2024-01-02 12:39
Added translation

2023-11-07 10:58
Section 657 Additional information form has been updated to include that the form must be submitted in advance of, or at the same time as, the Company Tax Return.

2023-10-09 15:56
Sections 275 and 280 have been updated to include that any missing information will delay the process or we may reject the claim.

2023-08-08 17:34
Information about the Research and Development claim notification form and the additional information form for boxes 656 and 657 has been updated.

2023-07-11 10:31
Guidance to complete boxes 326, 630 and 631 has been updated to include information about very large companies.

2023-04-14 13:37
Guidance to complete box 245 has been updated with reference to section 76 of the Finance Act 2012 and a link to the Life Assurance Manual LAM04000: Adjusted BLAGAB management expenses. Guidance to complete box 780 has been updated with reference to the BLAGAB (life insurance) losses which fall within section 78(5) of the Finance Act 2012.

2023-04-06 13:52
Guidance to complete box 230 has been updated to include the correct boxes in the calculation.

2023-04-06 12:01
Department for International Trade (DIT) has now changed to the Department for Business and Trade (DBT).

2023-04-01 00:15
Guidance to complete boxes 326, 327, 328, 329, 497, 501, 656, 657, 659 and 986 has been added. Guidance to complete boxes 435, 500, 510 and 625 has been updated.

2023-01-13 08:13
Guidance to complete box 620 has been updated to confirm new legislation s18L(3) will replace s279G(3) of the Corporation Tax Act 2010 for financial year 2023.

2022-11-10 15:55
Guidance to complete box 845 and 850 has been updated to include the word ‘excess’ andto remove information about qualifying charitable donations.

2022-11-02 13:11
Guidance to complete boxes 695 and 700, 705 and 710 has been updated to adviseyou that amounts from boxes 693 and 691 should not be included.

2022-10-28 15:33
Guidance to complete boxes 830, 835 and 850 has been updated with more information on how to claim non-trading losses on intangible fixed assets and excess amounts of management expenses.

2022-10-21 11:31
A link to the information about the ‘New tax regime for asset holding companies’ has been removed and replaced with a link to information about ‘Make a qualifying asset holding company notification to HMRC guidance’ in the ‘Qualifying Asset Holding Company’ section.

2022-09-30 10:18
First published.