UK Corporation Tax Calculator
Estimate Corporation Tax and Marginal Relief for an ordinary UK-resident company using its taxable total profits.
LedgerKit provides estimates based on the information entered and the configured rates. Results do not constitute accounting, tax or legal advice. Check the latest official guidance or consult a qualified professional before acting on a calculation.
How this calculator works
Enter taxable total profits after the relevant tax adjustments, expenses, capital allowances, losses and reliefs. This is not turnover and may differ from the profit shown in the company accounts.
Relevant exempt distributions are added to taxable total profits to produce augmented profits. Augmented profits decide which rate treatment applies, but Corporation Tax is charged only on taxable total profits.
For 2026/27, the small profits rate is 19%, the main rate is 25%, and Marginal Relief applies between the adjusted £50,000 and £250,000 limits. A short accounting period and associated companies reduce both limits.
This estimator is for an ordinary UK-resident company with non-ring-fence profits. It does not cover close investment-holding companies, non-UK resident companies, special regimes, tax credits, surcharges or quarterly instalment payments.
Worked example
For a full 12-month period, £100,000 taxable total profits, no relevant distributions and no other associated companies gives £25,000 tax at the main rate less £2,250 Marginal Relief. Estimated Corporation Tax is £22,750, an effective rate of 22.75%.
Frequently asked questions
Is Corporation Tax based on turnover?
No. It is based on taxable total profits, which can differ from both turnover and accounting profit. Enter the figure after the relevant tax adjustments and reliefs.
Why is my result not exactly 19% or 25%?
Companies with augmented profits between the adjusted limits normally pay 25% less Marginal Relief. This produces an effective rate between the small profits rate and the main rate.
What is an associated company?
Broadly, companies are associated where one controls the other or both are under common control. Some dormant or passive companies are disregarded. The rules can be complex, especially for family-owned companies, so ask an adviser if unsure.
Do dividends received affect the result?
Some exempt distributions from non-group, unassociated companies increase augmented profits and can change the rate treatment, even though tax is not charged on that distribution itself. Do not enter dividends paid by the company.
What if the accounting period is shorter than 12 months?
The £50,000 and £250,000 limits are reduced in proportion to the exact number of days. A Corporation Tax accounting period cannot be longer than 12 months.
Does this file the Company Tax Return?
No. It provides an estimate only. It does not prepare or submit the CT600, accounts or tax computation, and it does not send anything to HMRC.