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How Is Corporate Income Tax Calculated in the UK

Updated: Aug 22

What is Corporation Tax?

Corporate income tax in the United Kingdom is a complex subject that involves various rules and regulations. A UK resident company is taxed on its worldwide total profits, which include net income from different sources and net chargeable gains arising from the sale of capital assets. The main sources of income include profits from trade, property business, non-trading profits or losses from loan relationships, non-trading gains or losses on intangible fixed assets, and non-exempt dividends or other company distributions.

How Is Corporate Income Tax Calculated in the UK

Corporation Tax in the UK is a corporate tax levied on the annual profits made by UK resident companies and branches of overseas companies. The current rate is 25% for all limited companies, with a small profits rate (SPR) of 19% for companies with profits of £50,000 or below.

Income Determination

The determination of income is based on the company's accounts, with specific adjustments. The rules for measuring gross income differ for each category, and there are subtle differences in tax deductions and how gains are calculated. The basic rules for accounts-based sources include adjustments for non-trading receipts, non-deductible expenditure, depreciation for tax purposes (known as capital allowances), and other statutory adjustments.

Trading Profits

The main source of profits often comes from trading. A company's trading profits are based on its worldwide profit before tax in its accounts. Adjustments are made for non-trading receipts and non-deductible expenditure. Depreciation for tax purposes is calculated and substituted for the depreciation charged in the accounts. There are also specific rules for pension contributions, deferred pay, benefits in kind, and certain acquired intangibles.

Property Business Profits

Similar principles apply to the calculation of profits of a property business. Financial profits from a company's trading and non-trading loan relationships are usually based on the accounts, and the distinction between 'capital' and 'revenue' receipts and deductions is not relevant.

Income Losses

The UK tax system has detailed rules regarding the possible offset of income losses. Carryback and sideways reliefs are often allowed within limits, and carryforward is generally allowed. Losses can also be utilized by other group companies.

Capital Gains

Gains on capital assets are taxed at normal corporation tax rates. The chargeable gain is calculated by deducting costs of acquisition, subsequent improvements, and incidental costs of sale. Special rules apply to assets held at 31 March 1982, and for the disposal of UK immovable property by non-UK residents.

The calculation of corporate income tax in the UK involves understanding various sources of income, deductions, capital gains, and losses. The rules are intricate and require careful consideration of the company's accounts, trading activities, property business, and other financial relationships.

Who Pays and Who is Responsible?

All taxable UK limited companies must pay Corporation Tax, including unincorporated organizations like co-operatives, trade and housing associations, and members, clubs, or associations. The company director(s) are responsible for filing Corporation Tax returns with HMRC and ensuring all taxes are paid by the appropriate deadline.

How and When is Corporation Tax Paid?

Corporation Tax can be paid electronically, at a bank, or at a post office. Payment methods include CHAPS, BACS transfers, direct debits, and credit or debit card payments. The return deadline is usually 12 months after the end of the accounting period, and the payment deadline is usually 9 months and one day after the accounting period ends.

Penalties and Consequences

Penalties apply for missing the Corporation Tax return filing deadline, ranging from £100 to an additional 10% of any unpaid Corporation Tax. Penalties also apply for not paying Corporation Tax on time, including interest on the balance outstanding and potential legal actions.

Inaccurate Information and Fines

Submitting inaccurate information with a Corporation Tax return can result in fines ranging from 0-100% of the total Corporation Tax bill, depending on the severity of the inaccuracy and whether it was deliberate or accidental.

Trends and Thresholds

The Corporation Tax rate in the UK has been getting lower since 2010, reaching 19% from 2017 to April 2023, and then increasing to 25%. There is no Corporation Tax threshold, and all limited companies pay Corporation Tax on their profits.

Ring Fence Corporation Tax (RFCT)

RFCT is paid by companies involved in the production of oil and gas in the UK and the UK Continental Shelf. The main rate is 30%, and there is also a small profits rate of 19%.

Dividends and Sole Traders

Dividends are not subject to Corporation Tax, and sole traders do not pay Corporation Tax but are required to pay Income Tax on their business profits via self-assessment.

How to Pay Less Corporation Tax?

Companies can ensure tax efficiency through careful tax planning, including:

· Tax relief on property and equipment through capital allowance claims.

· Tax relief for innovative companies through R&D tax credits.

· Patent box tax relief.

Understanding Corporation Tax in the UK is essential for businesses, as it affects various aspects of operations, compliance, and financial planning. From rates and responsibilities to penalties and planning, this comprehensive guide provides valuable insights into everything you need to know about Corporation Tax in the UK for 2023.

Taxes on Corporate Income in the UK

General Corporation Tax Rates

The main rate of corporation tax in the UK is 25% for the financial year beginning 1 April 2023, previously 19% for the financial year beginning 1 April 2022. Additionally, from 1 April 2023, a 19% small profits rate of corporation tax was introduced for companies whose profits do not exceed GBP 50,000. Where taxable profits can be attributed to the exploitation of patents, a lower effective rate of 10% applies.

Special Corporation Tax Regimes

  1. Oil and Gas Company Regime: Profits from oil or gas extraction are subject to a full rate of 30%, with a supplementary charge of 10% on 'adjusted' ring-fence profits. Enhanced incentives include 100% capital allowances on most capital expenditures and extended loss carryback rules. A new 25% Energy Profits Levy (EPL) has been implemented, with changes announced in November 2022.

  2. Life Insurance Company Regime: Life insurance businesses are taxed under a special regime with different corporation tax rates and special rules for quantifying profits.

  3. Tonnage Tax Regime: Companies operating qualifying ships can elect to apply Tonnage Tax instead of corporation tax, calculating profits by reference to the net tonnage of operated ships.

  4. Banking Sector: A supplementary tax of 3% applies to companies in the banking sector on profits exceeding GBP 100 million from 1 April 2023.

  5. Real Estate Investment Trust (REIT) Regime: REITs are exempt from UK tax on rental income and gains relating to qualifying property rental business.

  6. Qualifying Asset Holding Company (QAHC) Regime: Introduced in April 2022, QAHCs must be at least 70% owned by diversely owned funds or certain institutional investors and are allowed tax exemptions/benefits in specific areas.

  7. Residential Property Developer Tax (RPDT): Introduced from 1 April 2022, RPDT applies at a rate of 4% to annual profits exceeding GBP 25 million from residential property development activity.

  8. Diverted Profits Tax (DPT): DPT was increased from 25% to 31% from 1 April 2023, targeting transactions or entities that lack economic substance or where foreign companies avoid a UK Permanent Establishment (PE).

Other Notable Taxes and Regulations

  • Income Tax for Non-Resident Companies: Non-resident companies are subject to UK corporation tax on trading profits of a UK PE, trading profits attributable to dealing in or developing UK land, and profits from a UK property rental business.

  • Local Income Taxes: There are no local or provincial taxes on income in the UK, although legislative powers exist to introduce a reduced rate of corporation tax in Northern Ireland.

The UK's corporate income tax system is multifaceted, with various rates and special regimes applicable to different sectors and types of businesses. Understanding these nuances is essential for companies operating in the UK, as it directly impacts their tax liabilities and compliance requirements.

Corporation Tax Rates, Allowances, and Reliefs in the UK

Corporation Tax Rates, Allowances, and Reliefs in the UK

Current Corporation Tax Rates

The Corporation Tax rate for company profits in the UK is 25%. The rate that applies to a company depends on its profit levels:

  • Main Rate: If a company made more than £250,000 profit, it pays the main rate of Corporation Tax, which is 25%.

  • Small Profits Rate: If a company made a profit of £50,000 or less, it pays the 'small profits rate,' which is 19%.

  • Marginal Relief: Companies with profits between £50,000 and £250,000 may be entitled to 'Marginal Relief.' All businesses that report profits between £50,001 and £250,000 will be eligible for a 26.5 percent marginal relief. This relief is designed to gradually increase the corporation tax rates for companies whose profits fall within these limits.


  • A company with a taxable profit of £85,000 will pay a 19 per cent tax on the first £50,000, and then a 26.5 per cent tax on the remaining amount up to £250,000. The total tax liability in this case would be £18,775.

  • If the profit were to rise to £250,000, the same calculation would be applied, resulting in a corporation tax liability of £62,500.

The £50,000 and £250,000 profit thresholds are proportionately reduced for short accounting periods and by the total number of 'associated companies' a company has. Different rates apply to 'ring fence' profits of companies involved in oil rights or extraction in the UK or UK continental shelf.

Previous Rates

From 1 April 2015 to 31 March 2023, a single rate of Corporation Tax applied to all companies. The rate of profits from before 1 April 2015 depends on the size of the profits.

Calculating Tax for Multiple Rates in an Accounting Period

If more than one rate applies in an accounting period, companies must work out how many days each rate is applied and then calculate the tax due for each. For example, if the accounting period is from 1 January 2023 to 31 December 2023:

  • The rate for the financial year starting 1 April 2022 applies for 90 days (1 January 2023 to 31 March 2023).

  • The rate for the financial year starting 1 April 2023 applies for 275 days (1 April 2023 to 31 December 2023).

Allowances and Reliefs

Companies may be able to get deductions or claim tax credits on their Corporation Tax. These are known as allowances and reliefs, and they can significantly impact the final tax liability.

Understanding the Corporation Tax rates, how they apply to different profit levels, and the allowances and reliefs available are essential for UK companies. The rates and rules can be complex, especially when multiple rates apply within an accounting period, and companies must be diligent in their calculations to ensure compliance with the law.

Exceptions, Provisions, and Specific Rules for UK Corporation Tax in 2023

New 2023 Corporation Tax Rates for UK Companies

The basic rate of 25% will be applied from 1 April 2023, with smaller entities retaining the previous 19% rate. Marginal relief will be implemented for businesses with profits between £50,001 and £250,000, resulting in a gradual increase in corporation tax rates.

Exceptions and Provisions for Introducing New Corporation Tax Rates

  1. Companies with Short Tax Years: Thresholds for the full 25% tax rate or the lower small profits rate will be reduced proportionally based on the number of trading months within the reduced reporting period.

  2. Reporting Periods Straddling 1 April 2023: Companies with corporation tax reporting periods that finish at any time other than 31 March will have their corporation tax obligations time apportioned.

  3. Rules for Associated Companies: New associated company rules will replace the previous group company test. The thresholds relevant to corporation tax are divided by the count of associate companies, reducing the £50,000 small profits rate and £250,000 standard corporation tax threshold depending on how many associate companies are involved within the same control structure or subsidiary structure.

  4. Substantial Commercial Interdependence: Companies need to assess whether they are associated by way of financial, economic, or organizational dependence on each other.

Corporation Tax for Ring Fence Companies

Ring fence companies profit from oil or extraction rights in the UK, and corporation tax rates vary. Effective corporation tax rates differ from other company structures, with specific rates for companies with profits less than £50,000, less than £300,000, over £250,000, and over £1.5 million.

UK Corporation Tax for Global Companies

Corporation tax is levied on all residential companies in the UK against their worldwide profits. Non-resident companies pay UK corporation tax only on the trading profits derived from trade within the UK or that deal with or involve developing British land.

Considerations for Specific Business Types

The change to corporation tax rates should be unambiguous for most UK-only businesses, but other considerations apply if they are:

  • Associate businesses with any other company or companies.

  • A UK branch or hub of an international company.

  • A ring fence company.

  • Trading within a short accounting period.

  • Dormant or passive companies.

  • Filing accounts that fall into both the 2022/23 and 2023/24 tax years.

Professional guidance may be necessary for complex scenarios.

The changes to UK corporation tax rates from 1 April 2023 introduce new complexities, especially for associated companies, global businesses with UK offices, and other commercial entities that fall outside standard terms and definitions. Understanding these exceptions, provisions, and specific rules is crucial for compliance and strategic planning.

Step-by-Step Guide to Calculating Corporate Income Tax in the UK

Step-by-Step Guide to Calculating Corporate Income Tax in the UK

Calculating corporate income tax in the UK involves several steps, taking into account various factors such as profits, allowances, reliefs, and specific tax rates. Here's a step-by-step guide to help you understand the process:

Step 1: Determine Taxable Profits

Identify Gross Profits: Start by identifying the company's gross profits from all sources, including trading profits, investments, and capital gains.

Deduct Allowable Expenses: Subtract all allowable business expenses, such as salaries, rent, utilities, and interest on loans.

Apply Capital Allowances: Deduct capital allowances for assets like machinery, equipment, and vehicles.

Consider Losses: If the company has any carried-forward losses, these can be deducted from the profits.

Step 2: Apply the Relevant Tax Rate

Identify Appropriate Rate: Determine the applicable corporation tax rate based on the company's profits. For 2023, the main rate is 25%, and the small profits rate is 19% for profits up to £50,000.

Consider Marginal Relief: If profits are between £50,000 and £250,000, calculate marginal relief to determine the effective tax rate.

Step 3: Calculate Preliminary Tax Liability

Multiply Taxable Profits by Rate: Multiply the taxable profits by the applicable corporation tax rate (or effective rate if marginal relief applies) to calculate the preliminary tax liability.

Step 4: Apply Reliefs and Credits

Research Available Reliefs: Identify any available reliefs and credits, such as Research & Development (R&D) tax credits or Patent Box relief.

Deduct Reliefs and Credits: Deduct the value of these reliefs and credits from the preliminary tax liability to arrive at the final tax liability.

Step 5: Consider Special Regimes (If Applicable)

Identify Special Regimes: Determine if the company falls under any special tax regimes, such as oil and gas companies or Real Estate Investment Trusts (REITs), and apply the relevant rules.

Step 6: File Corporation Tax Return

Prepare CT600 Form: Complete the Corporation Tax Return (CT600) form, including all necessary schedules and supporting documents.

Submit to HMRC: File the return with HM Revenue and Customs (HMRC) within 12 months after the end of the accounting period.

Step 7: Pay the Corporation Tax

Determine Payment Deadline: The payment deadline is usually 9 months and one day after the end of the accounting period.

Choose Payment Method: Pay the tax using an accepted payment method, such as online banking or direct debit.

Calculating corporate income tax in the UK is a detailed process that requires careful consideration of profits, expenses, allowances, reliefs, and specific tax rates. Following this step-by-step guide can help businesses accurately determine their tax liability and ensure compliance with UK tax laws.

Real-Life Example of Calculating Corporate Income Tax in the UK

Let's consider a real-life example of a UK-based company, "Tech Innovators Ltd.," to illustrate the step-by-step process of calculating corporate income tax for the financial year 2023/24.

Company Profile:

  • Gross Profits: £400,000

  • Allowable Expenses: £150,000

  • Capital Allowances: £50,000

  • Carried-Forward Losses: £10,000

  • R&D Tax Credits: £5,000

Step 1: Determine Taxable Profits

Gross Profits: £400,000

Minus Allowable Expenses: £150,000

Minus Capital Allowances: £50,000

Minus Carried-Forward Losses: £10,000

Taxable Profits: £400,000 - £150,000 - £50,000 - £10,000 = £190,000

Step 2: Apply Relevant Tax Rate

Since the taxable profits are £190,000, the small profits rate of 19% applies.

Tax Rate: 19%

Step 3: Calculate Preliminary Tax Liability

£190,000 * 19% = £36,100

Step 4: Apply Reliefs and Credits

Minus R&D Tax Credits: £5,000

Final Tax Liability: £36,100 - £5,000 = £31,100

Step 5: Consider Special Regimes (If Applicable)

Tech Innovators Ltd. does not fall under any special tax regimes.

Step 6: File Corporation Tax Return

Complete and submit the CT600 form to HMRC, including all necessary details and supporting documents.

Step 7: Pay the Corporation Tax

Pay the final tax liability of £31,100 by the appropriate deadline using an accepted payment method.

In this example, Tech Innovators Ltd. calculated its corporate income tax liability by considering various factors such as gross profits, allowable expenses, capital allowances, carried-forward losses, and R&D tax credits. The final tax liability amounted to £31,100, reflecting a comprehensive understanding of the UK's corporate income tax rules and regulations.

Corporate Income Tax Calculator

The Importance of Tax Software in Corporate Tax Management

In the complex world of corporate taxation, managing and complying with tax obligations can be a daunting task. This is particularly true in the UK, where corporate income tax laws are multifaceted and subject to frequent changes. Utilizing tax software can significantly ease this burden, providing businesses with a streamlined approach to tax calculation, filing, and planning. Here's how tax software can assist with corporate income tax in the UK.

Accurate Calculations: Eliminating Human Error

Automated Calculations

Tax software automates the calculation process, ensuring that all relevant factors such as gross profits, allowable expenses, capital allowances, and tax credits are accurately considered. This minimizes the risk of human error, which can lead to incorrect tax liabilities and potential penalties.

Real-Time Updates

Tax laws and rates often change, and keeping up with these changes can be challenging. Tax software provides real-time updates, ensuring that the latest tax rates and regulations are applied to the calculations.

Compliance: Meeting Legal Obligations

Timely Filing

Corporate income tax returns must be filed within specific deadlines. Tax software offers reminders and scheduling features, helping businesses to file their returns on time and avoid late filing penalties.

Adherence to Regulations

Understanding and adhering to all relevant tax regulations can be complex. Tax software guides businesses through the compliance process, ensuring that all legal obligations are met, including special tax regimes and reliefs that may apply.

Planning and Strategy: Maximizing Tax Efficiency

Scenario Analysis

Tax software allows businesses to run various tax scenarios, analyzing the potential impact of different business decisions on their tax liabilities. This enables strategic planning and helps companies make informed decisions that align with their financial goals.

Utilizing Tax Reliefs and Credits

The UK offers various tax reliefs and credits to encourage business investment and innovation. Tax software helps identify and apply these benefits, ensuring that companies take full advantage of available incentives.

Collaboration and Integration: Streamlining Processes

Multi-User Collaboration

Tax software often supports multi-user collaboration, allowing different departments within a company to work together seamlessly. This fosters efficient communication and ensures that all relevant information is considered in the tax calculation process.

Integration with Accounting Systems

Many tax software solutions integrate with existing accounting systems, allowing for a smooth flow of financial data. This integration ensures that all financial records are consistent and up-to-date, further enhancing accuracy and efficiency.

A Vital Tool for Modern Businesses

Tax software has become a vital tool for modern businesses in the UK, offering a comprehensive solution to corporate income tax management. From accurate calculations and legal compliance to strategic planning and seamless integration, tax software provides a range of benefits that simplify the complex world of corporate taxation.

By leveraging technology, businesses can navigate the intricate landscape of UK corporate income tax with confidence, ensuring accuracy, compliance, and efficiency. Whether a small business or a large corporation, investing in tax software is a strategic move that can lead to significant time and cost savings, allowing companies to focus on growth and success.

The Role of a Tax Accountant in Corporate Taxation

The Role of a Tax Accountant in Corporate Taxation

Corporate income tax in the UK is a complex and multifaceted area that requires careful navigation. With various rates, reliefs, allowances, and compliance requirements, managing corporate taxes can be a challenging task for businesses. A tax accountant, specialized in understanding and applying tax laws, can play a crucial role in assisting companies with their corporate income tax obligations. Here's how a tax accountant can help.

Expertise in Tax Laws: Navigating Complexity

In-Depth Understanding

Tax accountants possess an in-depth understanding of UK tax laws, regulations, and policies. Their expertise enables them to interpret complex tax codes, ensuring that businesses comply with all legal requirements.

Staying Up-to-Date

Tax laws frequently change, and staying abreast of these changes is vital. Tax accountants continuously update their knowledge, ensuring that they apply the most current laws and regulations to a company's tax situation.

Accurate Calculations: Minimizing Errors

Precision in Numbers

Calculating corporate income tax involves various factors, including profits, expenses, allowances, and credits. Tax accountants ensure that these calculations are precise, minimizing errors that could lead to penalties or additional tax liabilities.

Tailored Solutions

Every business is unique, and a tax accountant can provide tailored solutions that consider a company's specific circumstances. This personalized approach ensures that the tax calculations accurately reflect the business's financial situation.

Strategic Tax Planning: Maximizing Efficiency

Long-Term Planning

Tax accountants assist in long-term tax planning, helping businesses align their tax strategies with overall business goals. This includes optimizing tax reliefs, credits, and allowances to minimize tax liabilities.

Scenario Analysis

By analyzing different tax scenarios, tax accountants can help businesses make informed decisions. Whether considering expansion, investment, or restructuring, a tax accountant can provide insights into the potential tax implications.

Compliance and Reporting: Meeting Legal Obligations

Timely Filing

Filing corporate income tax returns on time is essential to avoid penalties. Tax accountants manage the filing process, ensuring that all documents are submitted within the required deadlines.

Comprehensive Reporting

Tax accountants prepare comprehensive tax reports that meet the standards set by HM Revenue and Customs (HMRC). These reports include all necessary details, schedules, and supporting documents, ensuring full compliance with legal requirements.

Representation and Negotiation: Advocacy and Support

Dealing with HMRC

Should any issues arise with HMRC, such as audits or disputes, a tax accountant can represent the company. Their expertise in tax laws enables them to advocate on behalf of the business, ensuring that its interests are protected.

Negotiating Settlements

In cases of disputes or disagreements with tax authorities, tax accountants can negotiate settlements. Their understanding of legal procedures and negotiation skills can lead to favorable resolutions for the company.

Collaboration and Communication: Building Strong Relationships

Collaborative Approach

Tax accountants often work closely with other departments within a company, such as finance and legal teams. This collaborative approach ensures that all relevant information is considered in the tax process.

Clear Communication

Tax accountants communicate complex tax matters in clear and understandable terms. They act as a bridge between the technical world of taxation and the practical needs of the business, ensuring that all stakeholders understand the tax implications of various decisions.

A Valuable Partner in Corporate Taxation

A tax accountant is a valuable partner for businesses navigating the intricate landscape of corporate income tax in the UK. From expertise in tax laws and accurate calculations to strategic planning and compliance, a tax accountant offers comprehensive support.

By leveraging the skills and knowledge of a tax accountant, businesses can ensure that they meet their legal obligations while optimizing their tax position. Whether a small start-up or a multinational corporation, engaging a tax accountant is a strategic investment that can lead to significant benefits, both in the short term and in the long run.

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