Free tax tool — 2026/27 tax year
Corporation Tax Calculator UK 2026/27
UK corporation tax is no longer a flat rate. Since April 2023, companies with profits between £50,000 and £250,000 pay an effective rate between 19% and 25% due to marginal relief. This calculator shows your exact corporation tax liability, your marginal relief deduction, and your effective tax rate for the 2026/27 tax year.
How to use: Enter your company's taxable profit for the accounting period. The calculator will show your tax at the small profits rate, main rate, or marginal relief band — whichever applies.
Understanding your results
If your taxable profits are £50,000 or below, you pay the small profits rate of 19%. If they are £250,000 or above, you pay the main rate of 25%. Between those thresholds, marginal relief applies — which means your effective rate gradually increases from 19% to 25%. At the margins, the effective rate on each additional pound of profit can be as high as 26.5%, which is why careful profit planning matters in the £50,000–£250,000 band.
If your company has associated companies (companies controlled by the same people), the £50,000 and £250,000 thresholds are divided between them. This can push a company into a higher effective rate. Dormant companies are excluded from this calculation.
Frequently asked questions
What is the corporation tax rate for small companies in 2026/27?
19% on taxable profits up to £50,000. This is called the small profits rate. Above £50,000, marginal relief applies until the full 25% main rate kicks in at £250,000.
When is corporation tax due?
Corporation tax is due 9 months and 1 day after the end of your accounting period. For example, if your year-end is 31 March 2027, payment is due by 1 January 2028. Your corporation tax return must be filed within 12 months of the year-end. Note that from 2026/27, late filing penalties have doubled.
How does marginal relief work?
Marginal relief reduces the amount of corporation tax for companies with profits between £50,000 and £250,000. It is calculated using a formula that tapers the effective rate from 19% up to 25%. The result is that companies in this band pay an effective rate somewhere between the two — for instance, a company with £100,000 profit pays approximately 21.5% overall.
Can I reduce my corporation tax bill?
Yes. Legitimate strategies include making pension contributions through the company (which are a deductible expense), claiming capital allowances on equipment, ensuring all allowable business expenses are captured, and timing major purchases to fall within the right accounting period. Research and development tax credits may also apply if your company innovates.
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Want help reducing your corporation tax bill?
A qualified accountant can identify deductions and reliefs that a calculator cannot. Book a free discovery call — no obligation.
Book a free discovery call →Provided by Grosvenor.Solutions. HMRC rates for 2026/27. For guidance only — does not constitute tax advice.