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What is a CT600 Form?

Updated: Nov 25, 2023

A corporate tax return is a vital aspect of running a business in the UK. It involves calculating the profits or losses of a business and paying the required tax to HM Revenue and Customs (HMRC). To do this, companies must complete a CT600 form, which is a self-assessment tax return form for corporation tax purposes. In this article, we will discuss the CT600 form for corporate tax returns in the UK, its requirements, and how to fill it out.


What is a CT600 form?

What is a CT600 form?

A CT600 form is a document used by companies to declare their taxable profits or losses for a specific accounting period. It is a self-assessment tax return form that companies must complete and file with HMRC within 12 months of the end of the accounting period. The accounting period is usually 12 months long and is set by the company. Companies must also keep records of their income, expenses, and other financial transactions during this period.


The CT600 form is part of a corporate tax return. The form and other supporting documents are the corporate tax return, which must be submitted to the HMRC when a company receives a "Tax Return Notice". Limited Liability Companies use the information in the CT600 form to calculate the corporate tax payable to them.



A limited liability company uses the CT600 form to file its tax return with the HMRC.


CT600 Form

Why Do I Have to Fill in the CT600 Form?

Some organizations, such as limited liability companies, pay corporation tax on the profits they get from trading and investment income. This also applies to other organizations such as corporations, clubs, clubs, and charities. Submit a CT600 and supporting documents so the HMRC knows how much corporation tax is due.



Who Needs to Complete CT600 in the UK?

In the UK, limited companies, as well as other corporate bodies that are subject to corporation tax, are required to complete a CT600 form for corporate tax return purposes. This includes UK-registered companies, such as private limited companies, public limited companies, and foreign companies that operate in the UK. Other entities that are required to file a CT600 form include clubs, societies, associations, and other non-profit organizations that are subject to corporation tax. It is important to note that if a company or organization is dormant and has no taxable income or gains during the accounting period, they are still required to submit a CT600 form to HMRC to notify them of their dormant status.





Should I Include My Overseas Profit in My CT600 Tax Return?

If the company is based in the UK, it pays corporation tax on all profits it makes, regardless of where it comes from. If the company is based overseas but operates through a UK branch or office, only UK-taxable profits will be taxed in the UK. Capital gains are also subject to corporation tax but are called taxable capital gains.


What are the Requirements for Corporate Tax?

There are three requirements that a company or any other organization must meet in relation to corporation tax:


● Inform HMRC that the corporation is a corporation tax.

● Pay the fee on time.

● Submit your tax return and any other documents before the deadline.


What are the Requirements for Filling Out A CT600 Form

To fill out a CT600 form for corporate tax returns in the UK, companies must meet certain requirements. Firstly, they must have a unique taxpayer reference (UTR) number, which is a 10-digit number assigned to them by HMRC. They must also have a Companies House registration number, which is a unique identification number assigned to them when they register with Companies House.


In addition to these requirements, companies must also have accurate financial records and information about their profits, losses, expenses, and other financial transactions for the accounting period. This information should be prepared in accordance with accounting standards, such as Generally Accepted Accounting Principles (GAAP), and should be verified by an independent auditor or accountant.


How to Fill out a CT600 Form

Filling out a CT600 form for corporate tax returns in the UK can be a complex and time-consuming process. It requires a thorough understanding of tax laws and regulations, as well as accounting principles and practices. Here are the steps involved in filling out a CT600 form:


Step 1: Gather Financial Records and Information

The first step in filling out a CT600 form is to gather all the financial records and information for the accounting period. This includes records of income, expenses, assets, liabilities, and other financial transactions. Companies must ensure that this information is accurate, complete, and prepared in accordance with accounting standards.


Step 2: Calculate Taxable Profits or Losses

The next step is to calculate the taxable profits or losses for the accounting period. To do this, companies must deduct allowable expenses from their income, such as salaries, rent, and other business expenses. They must also add any non-taxable income, such as dividends or interest, and make any necessary adjustments for capital allowances or losses.


Step 3: Complete the CT600 Form

Once the taxable profits or losses have been calculated, companies can begin filling out the CT600 form. The form consists of several sections, including details of the company, accounting periods, profits or losses, tax calculations, and other relevant information. Companies must ensure that all sections are completed accurately and in accordance with HMRC guidelines.


Step 4: Submit the CT600 Form

After completing the CT600 form, companies must submit it to HMRC along with any necessary supporting documents, such as financial statements, tax calculations, and other relevant information. Companies can submit the form online using HMRC's online service or by post. They must also pay any tax due by the deadline specified by HMRC.


Requirements for Filling Out A CT600 Form


How to Answer Different Questions in the Form CT600 (2023)


The questions in the CT600 form are not in a symmetrical order because they are organized according to the logical flow of tax computation and reporting requirements, rather than numerical symmetry. This structure reflects the complexities of corporate tax affairs, where different sections address varied aspects of a company's financial activities, such as income, deductions, reliefs, and specific tax calculations. The form is designed to guide companies through the sequential process of declaring their financial status, calculating tax liabilities, and providing necessary company details, aligning with the UK's tax regulations and accounting principles. This approach aids in accurate and comprehensive tax reporting.


Section: Company Information


Question 1: Company name

  • Answer: Enter the full legal name of the company as registered with Companies House.

Question 2: Company registration number

  • Answer: Provide the unique company registration number assigned by Companies House.

Question 3: Tax reference

  • Answer: Input the Unique Taxpayer Reference (UTR) number provided by HMRC.

Question 4: Type of company

  • Answer: Indicate the type of company, such as Northern Ireland (NI), SME, etc., by marking the appropriate box.

Question 5: NI trading activity

  • Answer: If the company has trading activities in Northern Ireland, mark 'Yes' in the corresponding box.

Question 6: SME

  • Answer: If the company qualifies as a Small and Medium-sized Enterprise (SME), mark 'Yes' in the corresponding box.

Question 7: NI employer

  • Answer: Indicate if the company is an employer in Northern Ireland by marking the appropriate box.

Question 8: Special circumstances

  • Answer: If any special circumstances apply, such as the company being part of a group, involved in avoidance schemes, etc., mark the relevant boxes.


Section: About this Return


Question 30: Accounting Period Start Date

  • Answer: Enter the start date of the accounting period for which this return is being filed (DD MM YYYY format).

Question 35: Accounting Period End Date

  • Answer: Enter the end date of the accounting period for this return (DD MM YYYY format).

Question 40: A repayment is due for this return period

  • Answer: Mark 'Yes' if a repayment from HMRC is expected for this period.

Question 45: Claim or relief affecting an earlier period

  • Answer: If any claim or relief affects an earlier period than the one reported, mark 'Yes' in the corresponding box.

Question 50: Making more than one return for this company now

  • Answer: Indicate if multiple returns for different periods are being filed concurrently for this company.

Question 55: This return contains estimated figures

  • Answer: If the return includes any estimated figures, mark 'Yes' in the corresponding box.

Question 60: Company part of a group that is not small

  • Answer: If the company is part of a non-small group, mark the relevant box.

Question 65: Notice of disclosable avoidance schemes

  • Answer: Indicate if there is any disclosable tax avoidance scheme to report.

Question 70: Compensating adjustment claimed

  • Answer: Mark 'Yes' if there are any compensating adjustments in transfer pricing.

Question 75: Company qualifies for SME exemption

  • Answer: Indicate if the company is eligible for any exemptions available to SMEs.



Section: About this Return


Question 80: I attach accounts and computations for the period to which this return relates

  • Answer: Mark 'Yes' if accounts and computations for the period of this return are attached.

Question 85: I attach accounts and computations for a different period

  • Answer: Indicate 'Yes' if the accounts and computations attached relate to a different period than this return.

Question 90: If you are not attaching the accounts and computations explain why

  • Answer: Provide a reason if accounts and computations are not attached.

Question 95 to 150: Supplementary pages enclosed

  • Answer: Mark the appropriate boxes to indicate which supplementary forms (e.g., CT600A, CT600B, etc.) are included with the return.


Section: Tax Calculation – Turnover


Question 145: Total turnover from trade £

  • Answer: Enter the total turnover amount from trade activities.

Question 150: Banks, building societies, insurance companies, and other financial concerns

  • Answer: Mark this box if applicable, especially when there is no recognized turnover to report.


Section: Income


Question 155 to 205: Various Income Related Entries

  • Answer: Fill in the relevant boxes with the amounts for trading profits, losses, interest, dividends, etc., as applicable to the company's financials.


Section: Chargeable Gains


Question 210 to 220: Gross Chargeable Gains and Allowable Losses

  • Answer: Enter the amounts for gross chargeable gains and any allowable losses, including losses brought forward.


Section: Profits Before Deductions and Reliefs


Question 225 to 235: Profits and Losses

  • Answer: Calculate and enter the net sum of profits before other deductions and reliefs, considering losses brought forward and non-trade deficits.


Section: Deductions and Reliefs


Question 240 to 295: Various Deductions and Reliefs

  • Answer: Enter relevant figures for losses on unquoted shares, management expenses, UK property business losses, capital allowances, etc.


Section: Profits Chargeable to Corporation Tax


Question 300 to 312: Calculating Profits Chargeable to Corporation Tax

  • Answer: Deduct qualifying donations, group relief, and other applicable amounts from the profits before tax to arrive at the profits chargeable to Corporation Tax.


Section: Tax Calculation - Continued


Question 320: Ring fence profits included

  • Answer: Enter the amount of ring fence profits included, if applicable.

Question 325: Northern Ireland profits included

  • Answer: Specify the amount of profits included from Northern Ireland operations.

Question 326 to 329: Associated Companies and Small Profit Rate

  • Answer: Provide the number of associated companies and indicate if the small profit rate or marginal relief applies.

Question 330 to 425: Corporation Tax Calculation

  • Answer: Calculate the amount of Corporation Tax due, considering the various rates and profits of the financial years.


Section: Tax Calculation – Reliefs and Deductions


Question 445 to 470: Tax Reliefs and Deductions

  • Answer: Enter the amounts for Community Investment Tax Relief, Double Taxation Relief, and Advance Corporation Tax if applicable.


Section: Coronavirus Support Schemes and Overpayments


Question 471 to 474: Coronavirus Job Retention Scheme (CJRS)

  • Answer: Declare any amounts received, entitled to, or overpaid under the CJRS and other coronavirus overpayments.



Section: Energy Profits Levy


Question 986: Energy (Oil and Gas) Profits Levy (EOGPL) amounts liable

  • Answer: Declare any amounts liable under the Energy Profits Levy, if applicable.


Section: Calculation of Tax Outstanding or Overpaid


Question 475 to 495: Net Corporation Tax Liability and Other Taxes Payable

  • Answer: Calculate the net Corporation Tax liability and declare any taxes payable on loans, controlled foreign companies, bank levy, etc.


Section: Tax Reconciliation


Question 530 to 570: Research and Development Credits

  • Answer: Enter any Research and Development credits and calculate any surplus credits payable.

Question 575: Land Remediation or Life Assurance Company Tax Credit Payable

  • Answer: Declare any payable land remediation or life assurance company tax credit.


Section: Exporter Information


Question 616 to 618: Export of Goods and/or Services

  • Answer: Indicate if the company exported goods and/or services outside the UK.


Section: Indicators and Information


Question 620 to 647: Various Indicators

  • Answer: Fill in relevant information regarding franked investment income, number of 51% group companies, instalment payments, intangible assets, cross-border royalty payments, etc.


Section: Information about Enhanced Expenditure


Question 650 to 670: Research and Development Expenditure

  • Answer: Provide information about R&D expenditure qualifying for SME R&D relief, creative enhanced expenditure, etc.


Section: Capital Allowances and Balancing Charges


Question 690 to 755: Capital Allowances and Charges

  • Answer: Declare the amounts for capital allowances and balancing charges, including super-deduction, special rate allowance, etc.


Section: Northern Ireland Information


Question 856 to 858: Group Relief Claims Related to Northern Ireland

  • Answer: Declare amounts of group relief claimed related to Northern Ireland trading losses and mainstream profits.


Section: Overpayments and Repayments


Question 860 to 895: Repayment Information

  • Answer: Provide details of any repayments of Corporation Tax, Income Tax, R&D tax credit, etc., if applicable.


Section: Bank Details


Question 920 to 940: Bank Details for Repayments

  • Answer: Fill in the bank or building society details where any repayments are to be made.


Section: Declaration


Question 975 to 985: Declaration of Accuracy

  • Answer: The person completing the return must declare that the information provided is correct and complete to the best of their knowledge.

(Note: The responses suggested are generic and should be tailored based on the specific circumstances and financial details of the company in question.)



Introduction to Corporation Tax for Company Tax Return Form CT600 (2023) Version 3

Corporation Tax is a tax levied on the profits of companies operating in the UK. The Company Tax Return Form CT600 (2023) Version 3 is used to report details related to the company's income, deductions, reliefs, and other financial information for accounting periods starting on or after 1 April 2015.


Company Information

The form begins with essential company details such as the company name, registration number, tax reference, and type of company. It also includes information about the accounting period, Northern Ireland trading activity, and special circumstances.


About the Return

This section explains the obligations of the company to comply with the filing date and provides information about penalties for non-compliance. It also outlines the components of a return, including supplementary pages, accounts, computations, and relevant information.


Income Tax Calculation

The form requires details about the company's turnover, trading profits and losses, interest, and other financial concerns. It includes specific boxes for banks, building societies, insurance companies, and other financial entities.


Deductions and Reliefs

This part of the form covers various deductions and reliefs, including losses on unquoted shares, management expenses, capital allowances, non-trade deficits, and more. It helps in calculating the net profits chargeable to Corporation Tax.


Chargeable Gains and Tax Calculation

The form includes sections for calculating gross chargeable gains, allowable losses, net chargeable gains, and the final tax calculation. It also includes provisions for marginal relief and the calculation of tax outstanding or overpaid.


Reliefs and Deductions in Terms of Tax

This section covers specific reliefs and deductions like Community Investment Tax Relief, Double Taxation Relief, Advance Corporation Tax, and Coronavirus support schemes.


Capital Allowances and Balancing Charges

The form provides detailed sections for capital allowances and balancing charges related to machinery, plant, buildings, electric charge-points, zero emissions vehicles, and more.


Losses, Deficits, and Excess Amounts

This part of the form deals with various losses, deficits, and excess amounts, including those related to trades, non-trade deficits, property business losses, capital losses, and more.


Overpayments and Repayments

The form includes provisions for handling small repayments, repayments for the period covered by the return, surrender of tax refund within the group, and Northern Ireland information.


Bank Details and Declaration

Finally, the form concludes with sections for providing bank details for repayments and a declaration that the information provided is correct and complete.


Filling out the CT600 (2023) Version 3 form is a comprehensive process that requires careful attention to detail. Understanding each section and the associated requirements is crucial for accurate reporting and compliance with UK tax laws. It's advisable to consult with a tax professional or refer to the detailed guidance provided by HMRC to ensure that the form is completed correctly.



What Should You Do If You Have Made a Mistake in Filling the Form CT600?

If you have made a mistake in filling out Form CT600 in the UK, it is important to rectify the error as soon as possible. Here are the steps you should follow:


  1. Identify the mistake: Carefully review your submitted CT600 form and identify the error(s) that need to be corrected.

  2. Amend the CT600 form: Prepare an amended CT600 form, which includes the corrected information. Make sure to double-check the amended form for accuracy before submitting it. You may also need to amend the accompanying documents, such as the company's financial statements or computations if they are affected by the changes made in the CT600.

  3. Submit the amended form: You can submit the amended CT600 form online through the HMRC's Corporation Tax online service, or by using commercial software that supports CT600 submission. If you are using the online service, you will need to sign in with your Government Gateway user ID and password. Once signed in, follow the steps to submit an amended return.

  4. Provide an explanation for the changes: When submitting the amended CT600, it is a good idea to provide an explanation for the changes made. This can help clarify the situation and prevent any potential confusion or queries from HMRC.

  5. Keep records: Retain copies of both the original and amended CT600 forms, along with any supporting documentation, for your records. You may need to refer to these documents in the future or provide them to HMRC if requested.

  6. Monitor the situation: After submitting the amended CT600, monitor your communication with HMRC to ensure that they have accepted the changes and updated your company's tax records accordingly. If you receive any correspondence from HMRC regarding the amended return, respond promptly and provide any additional information they may require.

  7. Seek professional advice: If you are unsure about how to correct the mistake or have concerns about the implications of the error, it is advisable to consult a professional accountant or tax adviser. They can help guide you through the process and ensure that your amended CT600 form is accurate and compliant with tax laws and regulations.


Remember that it is better to correct any mistakes as soon as possible, as this can help avoid potential penalties or interest charges related to the incorrect information.


What Happens If You Fail in Timely Filling the Form CT600 in The UK?

If you fail to file your Form CT600 (Corporation Tax Return) on time in the UK, you may face penalties and interest charges from HM Revenue and Customs (HMRC). The consequences of late filing can include:


Late filing penalties: HMRC imposes automatic penalties for late submission of the CT600 form, based on the length of the delay:


1. £100 penalty for filing up to 3 months late.

2. An additional £100 penalty if the CT600 is filed more than 3 months late (a total of £200).

If your company files late returns for three consecutive accounting periods, the £100 penalties are doubled to £200 each, meaning the total penalties could be £400.


  1. Tax-geared penalties: If the CT600 form is more than 6 months late, HMRC will charge an additional tax-geared penalty. This penalty is calculated as 10% of the unpaid Corporation Tax for the accounting period. If the form is more than 12 months late, another 10% penalty will be added, bringing the total tax-geared penalty to 20% of the unpaid Corporation Tax.

  2. Interest on unpaid tax: If you fail to pay the Corporation Tax by the due date, HMRC will charge interest on the unpaid tax, starting from the day after the payment was due until the date the tax is paid.

  3. Reputation risk: Late filing of your CT600 form can damage your company's reputation, as it may indicate poor financial management or non-compliance with tax laws and regulations.

  4. Potential HMRC scrutiny: Late or non-compliant filings can increase the risk of HMRC inquiries or investigations into your company's tax affairs.


To avoid these consequences, it is important to file your Form CT600 and pay any Corporation Tax due on time. It is advisable to consult a professional accountant or tax adviser to ensure that your company's tax affairs are managed accurately and in compliance with all applicable regulations.



How Can a Professional Accountant Help In The Form CT600 Processing?

A professional accountant can help in Form CT600 processing in the UK in several ways. Form CT600 is the Corporation Tax Return form that limited companies in the UK must file with HM Revenue and Customs (HMRC) to report their income, deductions, and tax liabilities for a given accounting period. Here are some ways a professional accountant can help with Form CT600 processing:


  • Compliance with Tax Laws and Regulations: A professional accountant is well-versed in the UK's tax laws and regulations, which can help ensure that your company's CT600 form is completed accurately and in compliance with all relevant rules.

  • Timely Submissions: An accountant can help you keep track of important deadlines and ensure that your CT600 is submitted on time, avoiding any penalties for late submissions.

  • Accurate Calculations: A professional accountant can help calculate your company's taxable profits, deductions, and allowances, ensuring that the right amount of Corporation Tax is paid.

  • Expert Advice: An accountant can provide expert advice on tax planning and strategies to help minimize your company's tax liabilities and maximize the available reliefs and allowances.

  • Record-keeping: Good record-keeping is essential for accurate tax returns. An accountant can help you maintain accurate financial records, which will make completing the CT600 form easier and more efficient.

  • Error Checking: An accountant can help review your CT600 form for errors or inconsistencies, reducing the likelihood of an HMRC enquiry or investigation.

  • Liaising With HMRC: If there are any queries or issues with your CT600 form, a professional accountant can liaise with HMRC on your behalf, helping to resolve any problems as quickly and efficiently as possible.

  • Ongoing Support: A professional accountant can provide ongoing support and guidance throughout the year, helping you stay informed about changes in tax laws and regulations that may affect your business.



In summary, a professional accountant can play a crucial role in Form CT600 processing in the UK by ensuring accuracy, compliance, and timely submissions, while providing valuable advice and support to help optimize your company's tax situation.



20 FAQs about CT600 Form


Q: Is there a specific software required to file the CT600 form electronically?

A: Yes, HMRC requires that the CT600 form be filed using compatible software that supports the HMRC's online filing system. This software should be able to generate and submit the form in the correct format.


Q: Can a CT600 form be amended after submission, and if so, how?

A: Yes, amendments can be made to the CT600 form after submission. This is typically done by filing an amended return using the same software used for the original submission. The process and rules for amendments may vary, so it's advisable to consult the software's guidance or HMRC's guidelines.


Q: Are there any specific guidelines for reporting Research and Development expenses on the CT600 form?

A: Yes, R&D expenses must be reported in specific sections of the CT600 form, and the company must ensure they meet the criteria for R&D tax credits. Detailed guidance on these requirements can be found in HMRC's R&D tax relief manual.


Q: What are the implications of incorrectly reporting the ring fence profits on the CT600 form?

A: Incorrect reporting of ring fence profits, which are profits from oil extraction or oil rights in the UK and UK continental shelf, can lead to inaccuracies in tax calculations and potentially result in penalties and interest for underpaid tax.


Q: How should a company with multiple branches report its profits on the CT600 form?

A: A company with multiple branches should consolidate the profits from all branches and report the total figure. If there are international branches, specific rules for foreign profits apply.


Q: What documentation is required to support the claims made on the CT600 form?A: Supporting documentation can include financial statements, detailed accounts, computations, and records of transactions and expenses. These documents should be retained for a period as specified by HMRC in case of an audit.


Q: How does a company report capital allowances on the CT600 form?

A: Capital allowances are reported in the capital allowances section of the CT600 form. Companies must calculate and claim these allowances based on eligible assets and expenditures.


Q: What are the specific requirements for reporting overseas income on the CT600 form?

A: Overseas income should be reported along with UK income, and companies must follow specific rules for foreign income, including relief for double taxation where applicable.


Q: How should a company report dividends received from other companies on the CT600 form?

A: Dividends received from other companies should be reported as part of the company's income. Specific rules apply to the taxation of dividends, depending on the source and type of dividend.


Q: Are there any special considerations for reporting losses carried forward on the CT600 form?

A: Yes, losses carried forward can be used to offset profits, but specific rules apply, including limitations on the use of losses from previous periods. Detailed rules can be found in HMRC guidelines.


Q: How does a company claim Double Taxation Relief on the CT600 form?A: To claim Double Taxation Relief, the company must report foreign tax paid on income that is also subject to UK tax. Specific sections in the CT600 form allow for this claim, and precise calculations must follow HMRC's guidelines.


Q: What is the process for reporting a change in accounting period on the CT600 form?

A: A change in the accounting period must be reported to HMRC and may require the filing of additional or amended CT600 forms. The process depends on whether the accounting period is being lengthened or shortened.


Q: How does a company declare its dormant status on the CT600 form?

A: A dormant company should file a CT600 form stating its dormant status. There are specific HMRC guidelines on how a company can declare itself dormant and the implications for tax filing.


Q: Are there any specific sections in the CT600 form for reporting government grants or subsidies?

A: Government grants or subsidies should be reported as part of the company's income or financial activities. Specific sections of the CT600 form may apply, depending on the nature of the grant or subsidy.


Q: How should a company handle the reporting of inter-company transactions on the CT600 form?

A: Inter-company transactions must be reported following transfer pricing rules and other relevant regulations. These transactions should be disclosed in the appropriate sections of the CT600 form.


Q: What are the guidelines for reporting the use of previous year’s losses on the CT600 form?

A: Previous year’s losses can be carried forward and offset against profits. The CT600 form includes sections where these losses can be reported, subject to HMRC's rules on loss relief.


Q: How to report income from intellectual property on the CT600 form?

A: Income from intellectual property should be reported as part of the company’s income. Specific rules may apply to the taxation of this income, and it should be declared in the relevant sections of the form.


Q: What are the reporting requirements for related party transactions on the CT600 form?

A: Related party transactions must be reported in compliance with transfer pricing rules. Detailed disclosure of these transactions is required to ensure they are conducted at arm's length.


Q: How does a company indicate its eligibility for SME exemptions on the CT600 form?

A: Companies eligible for SME exemptions should indicate this on the CT600 form, specifically in sections related to SME-specific tax reliefs or deductions.


Q: Are there specific sections in the CT600 form for environmental tax credits or deductions?

A: Yes, if a company is eligible for environmental tax credits or deductions, these should be reported in the relevant sections of the CT600 form, adhering to specific rules for such claims.









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