This corporation tax calculator works out the tax your limited company pays on its profits. It applies the 19% small profits rate, the 25% main rate and marginal relief between the two, and adjusts the limits for associated companies and short accounting periods.
Your Corporation Tax
- Corporation Tax
- –
- Effective rate
- –
- Marginal relief
- –
- Profit after tax
- –
In the example, a company with £120,000 of taxable profit pays £28,050.00 of Corporation Tax after £1,950.00 of marginal relief, an effective rate of 23.38%.
How to use the corporation tax calculator
- Enter your taxable profits: profit after allowable expenses and capital allowances, before dividends.
- Enter the number of associated companies, if any. The £50,000 and £250,000 limits are split between them.
- Enter the length of the accounting period if it is shorter than 12 months. The limits are reduced in proportion.
Corporation Tax rates
| Taxable profits | Rate |
|---|---|
| Up to £50,000 | 19% (small profits rate) |
| £50,001 to £250,000 | 25% less marginal relief |
| Over £250,000 | 25% (main rate) |
Marginal relief is worked out as 3/200 × (£250,000 − profits). It smooths the step between 19% and 25%, but it means profits between £50,000 and £250,000 are effectively taxed at 26.5% at the margin. See the GOV.UK marginal relief guidance.
Corporation tax calculator UK examples
| Profits | Marginal relief | Corporation Tax | Effective rate |
|---|---|---|---|
| £25,000 | £0 | £4,750 | 19.00% |
| £50,000 | £0 | £9,500 | 19.00% |
| £75,000 | £2,625 | £16,125 | 21.50% |
| £100,000 | £2,250 | £22,750 | 22.75% |
| £150,000 | £1,500 | £36,000 | 24.00% |
| £200,000 | £750 | £49,250 | 24.62% |
| £250,000 | £0 | £62,500 | 25.00% |
| £400,000 | £0 | £100,000 | 25.00% |
Associated companies and short periods
If one person or group controls two or more companies, they are associated, and the limits are divided between them. With one associated company, the lower limit becomes £25,000, so a company with £40,000 of profit pays £8,725.00 instead of £7,600. Dormant companies do not count.
For an accounting period shorter than 12 months, the limits are reduced in line with the number of days or months, which the calculator does for you.
How marginal relief works: a worked example
Take a company with £120,000 of profit. At the main rate, tax would be £30,000. Marginal relief is 3/200 × (£250,000 − £120,000) = £1,950.00. So the tax is £30,000 − £1,950.00 = £28,050.00. The corporation tax calculator does this sum for you and also checks whether your profits are below the lower limit or above the upper limit.
Each extra £1 of profit between £50,000 and £250,000 adds 26.5p of tax. That is worth knowing when deciding on the timing of large expenses or employer pension contributions, which reduce taxable profit.
When to pay and file
- Pay Corporation Tax 9 months and 1 day after the end of your accounting period, unless your profits are over £1.5 million, when you pay in quarterly instalments.
- File your Company Tax Return (CT600) within 12 months of the end of the period.
- Register for Corporation Tax within 3 months of starting to trade.
Paying yourself from a limited company
After Corporation Tax, profits can be paid out as dividends, which are taxed again on the shareholder. Use the dividend tax calculator to see the personal tax, or compare with being a sole trader using the self employed tax calculator.
Frequently asked questions
How much Corporation Tax do I pay on £100,000 profit?
£22,750.00, after £2,250.00 of marginal relief, for a 12-month period with no associated companies.
Is this a limited company tax calculator?
It calculates the tax the company pays on its profits. Directors also pay personal tax on salary and dividends, which you can work out with our other calculators.
Can I reduce Corporation Tax?
Claim all allowable expenses and capital allowances, including the Annual Investment Allowance on equipment, consider employer pension contributions, which are usually deductible, and check if you qualify for R&D relief.
Do I pay Corporation Tax on dividends received?
Most dividends a UK company receives from other companies are exempt. Enter only taxable trading and investment profits.
About this calculator
This corporation tax calculator uses the rates for the financial year starting 1 April 2026, checked against GOV.UK on 9 November 2026. It does not cover ring-fenced oil and gas profits or periods that span a rate change. Results are estimates; your accountant will confirm the figure on your CT600.