Corporation Tax calculator

An estimate. It takes the profits chargeable to Corporation Tax that you enter, and applies the rates for the financial years the period falls in. Nothing you enter is stored or sent: the sum is worked out in the page.

It does not work out the profit. The profit chargeable to Corporation Tax is the company's accounts profit after the adjustments in its tax computation, and the calculator takes it as you give it.

• From 1 April 2023 the main rate is 25%. A company with profits of £50,000 or less pays the small profits rate of 19%. Between £50,000 and £250,000 it pays the main rate less marginal relief.
• Marginal relief is worked out the way HMRC's own checks on a return work it out, to the penny. For profits between the limits it is 3/200 of the amount by which profit falls short of the upper limit.
• From 1 April 2017 to 31 March 2023 one rate of 19% applied to every company, and 20% in the two financial years before that. The calculator starts at 1 April 2015.
• A period that falls in two financial years is split by days, and each part is taxed at its own year's rate.
• A close investment-holding company pays the main rate on all its profits, with no small profits rate and no marginal relief.

Rates for a financial year later than the last one checked are taken to be unchanged, and the estimate says so when that happens.

Each limit is divided by one plus the number of associated companies, and reduced in proportion for an accounting period shorter than twelve months. Enter the number of other companies, not counting this one.

Whether companies are associated depends on who controls them. This software asks the owner for the number as a declaration for each period; it does not work it out.

• The profit itself: capital allowances, losses and other reliefs are not worked out here.
• Dividends received from other companies. Most are not taxed, but they count towards the limits, so a company that has received some may pay more than this shows.
• Tax on loans to directors and other participators (section 455), which is a separate charge.
• Payment by instalments, which a company with large profits makes on other dates.

Corporation Tax is due nine months and one day after the period ends. The filing deadlines page has that date and the others.

This page describes how the software works. It is not tax or legal advice, and a qualified accountant has not reviewed the calculations. Check the figure against the company's own computation before relying on it.

This software builds a company's books from its bank statements and works out the profit and the Corporation Tax for each period from them, so the figure is not typed in. See how it works.