Enter your company's taxable total profits and the length of the accounting period. The calculator applies the small profits rate of 19%, the main rate of 25% or Marginal Relief between the two, at the rates and limits HMRC publishes for the financial years starting on 1 April 2023, 2024, 2025 and 2026. You get the tax, the effective rate and the profit after tax, with the workings. The rates are the same for companies in England, Scotland, Wales and Northern Ireland.
Enter the taxable total profits
These are the profits chargeable to Corporation Tax for the accounting period: trading profits, investment income and chargeable gains, after allowances, reliefs and losses. Exempt distributions, such as dividends from companies outside your group, are not taxed, but they are added to the profits to decide which rate applies. HMRC calls the total 'augmented profits'.
Which rate applies
If augmented profits are £50,000 or less, the profits are taxed at the small profits rate of 19%. Above £250,000, they are taxed at the main rate of 25%. In between, the main rate applies and Marginal Relief reduces the tax, so that each extra pound of profit between the two limits is taxed at 26.5%.
Associated companies and short periods
The £50,000 and £250,000 limits are divided by one plus the number of associated companies: with three, they become £12,500 and £62,500. They are also reduced in proportion for an accounting period shorter than 12 months, such as a first period. HMRC strictly reduces them by the number of days in the period; this calculator works in months, as HMRC's own example does, so for a short period check the exact figure with HMRC's Marginal Relief calculator.
What the calculator does not cover
Close investment-holding companies and non-UK resident companies pay the main rate on all their profits: tick the box to see that. A non-resident company that a tax treaty's non-discrimination article entitles to the small profits rate or Marginal Relief leaves it unticked. Ring fence profits from oil and gas, the Bank Surcharge and unit trusts are taxed under other rules and are not covered. Amounts are rounded to the nearest penny, with halves rounded up.
Augmented profits (A) = taxable total profits (N) + exempt distributions.
A up to the lower limit: Corporation Tax = N × 19%.
A above the upper limit: Corporation Tax = N × 25%.
In between: Corporation Tax = N × 25% − 3/200 × (upper limit − A) × N ÷ A.
The limits, £50,000 and £250,000 for 12 months, are divided by one plus the number of associated companies and reduced in proportion for a shorter period.
Example: HMRC's company with £90,000 of profits
HMRC's manual works through a company with £90,000 of profits for the period to 30 September 2026, no associated companies and £8,000 of exempt distributions. Its augmented profits are £98,000, between the limits. Tax at the main rate is £22,500.00, and Marginal Relief is 3/200 × (£250,000.00 − £98,000.00) × £90,000.00 ÷ £98,000.00 = £2,093.88, so Corporation Tax is £20,406.12 (HMRC rounds to £2,094 and £20,406). That is an effective rate of 22.67%.
