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Corporation Tax Calculator

Enter your company's annual profit to see your 2025/26 UK corporation tax, effective rate, and profit after tax, with marginal relief applied automatically.

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Corporation tax
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Effective rate
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Profit after tax
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How UK corporation tax is calculated for 2025/26

Corporation tax has three tiers. Small profits pay 19%, large profits pay 25%, and profits in between get marginal relief that tapers the effective rate up from 19% towards 25%.

Worked example. A company with £100,000 profit pays £100,000 x 25% = £25,000, less marginal relief of 3/200 x (£250,000 - £100,000) = £2,250. Corporation tax is £22,750, an effective rate of 22.75%.

The thresholds

This calculator assumes no associated companies and a full 12-month accounting period. Both thresholds are divided if you have associated companies or a short period.

Source: gov.uk corporation tax rates. This is an estimate, not tax advice.

Frequently asked questions

What are the UK corporation tax rates for 2025/26?

Profits up to £50,000 are taxed at the 19% small profits rate. Profits of £250,000 or more are taxed at the 25% main rate. Between the two, marginal relief tapers the effective rate, so a company on £100,000 profit pays an effective 22.75%.

How does marginal relief work?

Between £50,000 and £250,000 the tax is the main rate (25%) less a reduction of 3/200 of the difference between £250,000 and your profit. This calculator assumes no associated companies and a 12-month accounting period.