Corporation Tax Calculator
UK 2025/26
Calculate your UK corporation tax bill for 2025/26 in seconds. This free corporation tax calculator includes automatic marginal relief for profits between £50,000 and £250,000. Enter your taxable profit below — instant results, no sign-up required.
| Taxable profit | — |
| Corporation tax rate | — |
| Corporation tax due | — |
| After-tax profit | — |
UK Corporation Tax Calculator — 2025/26 Rates & Rules
Our free corporation tax calculator is the most accurate UK tool for 2025/26, applying the exact HMRC rates including automatic marginal relief. Whether you are checking your liability before filing, planning your salary and dividend strategy, or comparing structures — this UK corporation tax calculator gives you instant answers. Below you will find a full explanation of how the rates work and how to use your results.
UK Corporation Tax Rates 2025/26
The corporation tax calculator above applies the correct 2025/26 rates automatically. UK limited companies currently pay corporation tax at two main rates, with a marginal relief band between them.
| Taxable Profit | Rate | Name |
|---|---|---|
| Up to £50,000 | 19% | Small Profits Rate |
| £50,001 – £249,999 | 19%–25% | Marginal relief band |
| £250,000 and above | 25% | Main Rate |
What is corporation tax marginal relief?
Marginal relief prevents companies earning just over £50,000 from suddenly paying 25% on all profit. Instead, the rate increases gradually from 19% to 25% as profits rise through the £50,000–£250,000 band. The HMRC formula is: Relief = (3/200) × (Upper Limit − Augmented Profits). Our marginal relief calculator handles this automatically.
How to Use This Corporation Tax Calculator
Step 1 — Calculate taxable profit
Your taxable profit is your net profit after deducting all allowable business expenses, capital allowances, and available reliefs. This is what you enter into our corporation tax calculator UK tool above.
Step 2 — Apply the correct 2025/26 rate
If your profit is £50,000 or below: 19% applies (Small Profits Rate). If your profit is £250,000 or above: 25% applies (Main Rate). For profits between these thresholds, enter your profit in the corporation tax calculator above — it applies marginal relief automatically. You can also use our dedicated marginal relief calculator for a detailed breakdown.
Step 3 — Account for associated companies
If your company has associated companies under common control, the £50,000 and £250,000 thresholds are divided by the number of associated companies plus one. For example, with one associated company, the thresholds become £25,000 and £125,000. Select the correct number in the calculator above.
Step 4 — Know your payment deadline
Corporation tax is due 9 months and 1 day after the end of your accounting period. For a 31 March year-end, payment is due by 1 January. Your CT600 company tax return must be filed within 12 months of your accounting period end.
⚠ This calculator gives estimates only
Real corporation tax calculations can include capital allowances, R&D credits, group relief, loss carry-forward, and other complex factors. Always have your CT600 prepared by a qualified accountant before submission to HMRC.
📊 Using this corporation tax calculator effectively
This corporation tax calculator UK tool works best when you enter your net taxable profit — after allowable expenses but before tax. If your company has associated companies, select the correct number from the dropdown to get accurate threshold adjustments. The corporation tax calculator will show you whether marginal relief applies and calculate it automatically.
How to Reduce Your Corporation Tax Bill Legally
There are several HMRC-approved ways to reduce how much corporation tax your company pays:
Employer pension contributions
Employer contributions to a director's pension scheme are a fully deductible business expense, reducing your taxable profit pound for pound. This is one of the most tax-efficient ways to extract money from a company.
Capital allowances
The Annual Investment Allowance lets you deduct 100% of qualifying plant and machinery costs (up to £1 million) in the year of purchase — reducing your taxable profit immediately rather than spreading the deduction over several years.
R&D tax credits
If your company develops new products, processes, or software, HMRC's R&D tax relief scheme can significantly reduce your corporation tax bill or generate a cash credit from HMRC.
Director salary and dividends
As a director, optimising your salary and dividend split affects your company's taxable profit. Salary is a deductible business expense — dividends are not. Use our dividend tax calculator to model the most efficient extraction strategy.
For a complete view of all taxes your limited company pays, including corporation tax, dividend tax, and salary costs, use our limited company tax calculator.