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UK Corporation Tax: A Comprehensive Guide for Small Business Owners

Michael Bush

Navigating the fiscal landscape of the UK can be a daunting task for many small business owners. One of the main pillars of this landscape is Corporation Tax – the tax payable on company profits. This guide is tailored to provide a comprehensive overview of UK Corporation Tax, helping small business owners understand their obligations and how to optimise their tax position.

1. What is Corporation Tax?

Corporation Tax is a tax on the profit of companies and certain other business entities, such as unincorporated associations. Profits for this purpose include both income and capital gains.

2. Who Pays Corporation Tax?

In the UK, if you run your business as a limited company or a foreign company with a UK branch or office, you’ll need to pay Corporation Tax. Sole traders and partnerships don’t pay Corporation Tax but are instead subject to Income Tax on their profits.

3. How is Corporation Tax Calculated?

The taxable profit for Corporation Tax is not the same as the total profit shown in your financial statements. Taxable profit is essentially:

Total Profit (from your P&L) - Allowable Business Expenses - Capital Allowances + Adjustments for Previous Losses

4. Corporation Tax Rates

The Corporation Tax rate can change annually. As of my last update in 2022, the main rate of Corporation Tax was 19%. However, business owners should always consult the HMRC website or their accountants to confirm the current rate.

5. Paying Corporation Tax

It’s important to note that there’s no invoicing or billing for Corporation Tax. Businesses are responsible for calculating, reporting, and paying this tax to HMRC. This process is typically managed through your Corporation Tax Self Assessment, which must be filed online.

6. Corporation Tax Payment Deadlines

Your Corporation Tax bill must be paid nine months and one day after the end of your accounting period, which usually coincides with the financial year end. For example, if your accounting period ended on 31st March, your Corporation Tax would be due on 1st January of the following year.

7. Reliefs and Allowances

To support businesses, there are a number of reliefs and allowances available:

  • Capital Allowances: Deductions you can claim for the cost of assets used in the business.
  • Research and Development (R&D) Relief: If your business is involved in innovation or improving existing processes, products, or services, you might qualify for R&D relief.
  • Terminal, Capital and Property Income Losses: If your company makes a loss, you might be able to offset this against profits.

8. Corporation Tax and Dividends

Dividends are not a business expense and hence are not deductible for Corporation Tax purposes. They’re taken out from post-tax profit. However, individuals receiving dividends have their own tax to consider, namely the Dividend Tax.

9. Avoiding Common Mistakes

Several common pitfalls can catch out small business owners:

  • Late Payment: Make sure to pay your tax bill on time to avoid penalties.
  • Inaccurate Records: Maintain diligent financial records and ensure that all allowable expenses and reliefs are claimed.
  • Not Using Professional Help: Engaging with an accountant can save time, provide clarity, and often save more than their fee in reduced tax liability or avoided penalties.

10. Changes in Legislation

Tax rules and regulations evolve. It’s essential to stay updated, either by regularly checking the HMRC website, subscribing to financial news, or through regular consultations with your accountant.


Managing Corporation Tax effectively is crucial for the financial health of your small business and ensures compliance with UK laws. By understanding its basics, staying updated with legislative changes, and possibly seeking the assistance of professionals, you can navigate this aspect of the fiscal landscape confidently.

Remember, while this guide provides a comprehensive overview, Corporation Tax intricacies can vary based on specific business situations. Always seek personalised advice and consultation with a qualified accountant to ensure full compliance and optimisation.

Note: While this guide aims to provide an overview of VAT for UK small businesses, it’s crucial to consult the latest regulations from HMRC or seek advice from a professional accountant for specific and up-to-date information.

Last Updated on October 16, 2023 by Michael Bush

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