Corporation Tax Calculator – 2025/26 tax year for limited companies

Quickly find out how much tax your limited company will pay on its profits during the 2025/26 tax year.

What are the current Corporation Tax rates?

From 1 April 2023, UK companies are taxed on their annual profits as follows:

• Profits up to £50,000 – taxed at 19%, known as the Small Profits Rate.
• Profits over £250,000 – taxed at 25%, the Main Rate.
• Profits between £50,001 and £250,000 – subject to a tapered rate (effective rate up to 26.5%) through Marginal Relief.

You can read more about the April 2023 CT tax rise in our background article.

Some Corporation Tax insights

• Marginal Relief is not automatic – it requires a specific calculation based on your profit level and the number of associated companies.
• Dividends aren’t deductible – only business-related expenses reduce your taxable profits.
• Accounting periods matter – Corporation Tax is calculated per accounting period, not per tax year.
• Tax is due nine months and one day after the end of your accounting period – don’t miss the deadline!

Corporation Tax Notes and Tips

• Associated Companies Rule: If you own or control multiple companies, your tax thresholds are divided between them, meaning you’ll hit the higher tax bands sooner. Find out more here.
• Investment and R&D Reliefs – These can significantly reduce your CT bill. Consider R&D tax credits, the Annual Investment Allowance, or the Patent Box scheme.
• Losses can be carried forward – If you make a loss during your current company tax year, it may reduce your future Corporation Tax bills.
• Remember to file your CT600. This is your official Corporation Tax return, and HMRC can issue penalties if it’s late. Your accountant should carry out this fundamental task.

This calculator is provided for illustrative purposes only. Please get in touch with your accountant if you have questions about your limited company’s tax situation.