Corporation tax calculator
Profit up to £50,000 is taxed at 19% and profit of £250,000 or more at 25%. In between, marginal relief applies, and the working below shows it line by line.
Rates for the 2026/27 tax year. Checked 6 November 2026.
| Taxable profit | £100,000.00 |
|---|---|
| Tax at 25% | £25,000.00 |
| Marginal relief, 3/200 of £150,000.00 | − £2,250.00 |
| Corporation tax | £22,750.00 |
| Effective rate | 22.8% |
| Left after tax | £77,250.00 |
Every £1 of profit between £50,000 and £250,000 is taxed at 26.5% at the margin, above the 25% main rate, because relief is being withdrawn.
Worked example: £100,000 profit
On £100,000 of profit the company pays £22,750, an effective 22.75%. Tax at 25% would be £25,000, and marginal relief is 3/200 of the gap to £250,000, so 3/200 of £150,000, or £2,250. Each extra pound in this range is taxed at 26.5% because relief is withdrawn as profit rises. That makes a pound of pension contribution or allowable expense worth more here than below £50,000.
Associated companies and short periods
The limits are shared between associated companies and scaled down for accounting periods under 12 months. For one company with a 12-month period, the figures here apply as they are.
When this calculator is wrong for you
- You have associated companies, including one your spouse controls.
- Your accounting period is not 12 months.
- Your profit includes exempt dividends received; they affect the limits, not the tax.
Questions people ask
When is corporation tax due?
Nine months and one day after the end of the accounting period. The return is due twelve months after.
Is salary deducted before corporation tax?
Yes. Salary, employer NI, pension contributions and allowable expenses all reduce taxable profit.
Why is my marginal corporation tax rate 26.5%?
Because marginal relief falls by 1.5p for every extra pound of profit, on top of the 25% rate.
Does the £50,000 limit change each year?
It has not changed since April 2023. The changelog records any change each April.
How this is worked out
Profit up to £50,000 is taxed at 19%. Profit of £250,000 or more at 25%. Between the limits, tax is 25% of profit less marginal relief of 3/200 multiplied by (£250,000 minus profit). Rounded to the penny.
Full formulas, rounding rules and test cases are on the methodology page. Every rate update is listed in the changelog.