Number of associated companies (excluding this one). This reduces the upper and lower profit thresholds proportionally.
Reg. 07380272 · England & Wales · Est. 2010
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Taxable Profits
£100,000.00
Corporation Tax
£22,750.00
Effective Rate
22.8%
Rate Band
Profit After Tax
£77,250.00
Profit Breakdown
Everything you need to know about UK corporation tax
How is corporation tax calculated?
Corporation tax is a tax on the profits of UK limited companies and some other organisations including clubs, societies, and unincorporated associations. From April 2023, the UK moved to a two-rate system with a small profits rate of 19% for companies with profits up to £50,000.00 and a main rate of 25% for profits above £250,000.00.
What is marginal relief?
Companies with profits between £50,000.00 and £250,000.00 fall into the marginal relief band. They pay the main rate of 25% but receive marginal relief, which gradually tapers the effective rate from 19% up to 25% as profits increase. This ensures there is no sudden jump in the tax bill when crossing the £50,000.00 threshold.
What are associated companies?
Associated companies are companies under common control. If you control multiple companies, the upper and lower profit thresholds are divided equally among them. For example, if you have one associated company (two companies total), the lower limit becomes £25,000 and the upper limit becomes £125,000. Dormant companies are generally excluded from the count.
Filing deadlines & penalties
Your company must register for corporation tax within 3 months of starting to trade. The CT600 return must be filed within 12 months of the accounting period end. Payment is due 9 months and 1 day after period end. Late filing incurs automatic penalties starting at £100.
HMRC-Aligned: Tax calculations use official HMRC rates and thresholds for the 2025/26 tax year (6 April 2025 – 5 April 2026). Results are indicative — for complex situations, consult a qualified accountant.
This calculator uses official rates and thresholds from:
Last verified: February 2026 · Tax year 2025/26. Results are indicative — consult a qualified accountant for personalised advice.
Reviewed by M. Samiuddin Quadri, ACCA — Chartered Certified Accountant at Gladstone & Co. · Updated for the 2025/26 tax year.
Disclaimer: This calculator provides estimates based on current HMRC rates and thresholds for the 2025/26 tax year. It does not constitute professional tax, financial, or legal advice. Your actual liability may differ depending on your individual circumstances. Always consult a qualified accountant or tax adviser before making financial decisions. Read our terms