Corporation tax calculator: the 2026/27 bill, done properly
Corporation tax for 2026/27 is 19% on profits up to £50,000 and 25% above £250,000, with marginal relief in between; rates are unchanged at the Autumn Budget 2025. The trap sits in the middle: every pound of profit between the limits is taxed at an effective 26.5%, higher than the headline rate anyone quotes. Enter your expected profit below and this page works out the bill, the relief and the rate you are really paying.
- corporation tax due for the year
- effective rate on your whole profit
- marginal relief deducted
- tax on your next £1 of profit
Now ring-fence it. The bill lands nine months and one day after year end, and the reserve does not have to sit at 0% while it waits:business savings accounts pay up to 3.91% easy access.
What the 2026/27 bill looks like
| Taxable profit | Corporation tax | Marginal relief | Effective rate |
|---|---|---|---|
| £30,000 | £5,700 | None | 19% |
| £60,000 | £12,150 | £2,850 | 20.25% |
| £100,000 | £22,750 | £2,250 | 22.75% |
| £150,000 | £36,000 | £1,500 | 24% |
| £250,000 | £62,500 | None | 25% |
The 26.5% band nobody quotes
Between £50,000 and £250,000 of profit, each additional pound is taxed at 26.5p, not the 19p or 25p in the headlines. The arithmetic: the 25% main rate applies to the whole profit, and the relief that softens it shrinks by 1.5p for every extra pound you earn, so the marginal cost is 25p plus 1.5p. This is why timing matters in the band. A £10,000 expense brought forward into this year, or a pension contribution made before year end, saves £2,650 rather than the £1,900 or £2,500 a director might expect, and profit pushed just past £50,000 by one good invoice starts costing 26.5% immediately.
How the calculation works
- Up to £50,000: the small profits rate. Tax is simply 19% of taxable profit.
- £50,000 to £250,000: start from 25% of profit, then subtract marginal relief of 3/200 of the distance from your profit up to £250,000. At £100,000: £25,000 minus £2,250 relief is £22,750, an effective 22.75%.
- Above £250,000: the main rate. Tax is 25% of the whole profit, no relief.
- Associated companies divide the limits. One associate halves them to £25,000 and £125,000; three associates quarter them. Common control is the test, so sister companies under the same owner count.
What this calculator assumes
A 12-month accounting period, no dividends received from other companies, and profits that equal augmented profits, which holds for most trading companies. Short periods scale the limits down proportionately, and distributions received push augmented profits up, which can pull relief away. Figures follow the HMRC rates table for the 2026 financial year; this page is a planning tool, not tax advice, so confirm the final computation with your accountant or HMRC's own calculator before filing.
Questions people actually ask
What is the corporation tax rate for 2026/27?
19% on profits up to £50,000 and 25% on profits above £250,000, unchanged since 2023. Between those limits the 25% rate applies with marginal relief, which works out as an effective 26.5% rate on each pound of profit inside the band.
How does corporation tax marginal relief work?
Companies with profits between £50,000 and £250,000 pay the 25% main rate minus a relief of 3/200 of the gap between £250,000 and their profit. The result: total tax lands between 19% and 25% of profit, but each extra pound earned inside the band suffers 26.5p of tax.
What are associated companies and why do they change the calculation?
Companies under common control count as associated, and the £50,000 and £250,000 limits are divided by one plus the number of associates. Two associated companies each get limits of £25,000 and £125,000, which drags marginal relief and the 25% rate down to much smaller profits.
When is corporation tax due?
Nine months and one day after the end of the accounting period for companies with profits up to £1.5 million. The company tax return itself is due twelve months after the period ends, so the money is owed before the paperwork.
Is corporation tax paid on turnover or profit?
Profit. Corporation tax is charged on taxable profits: trading income minus allowable expenses, plus chargeable gains. A company with £300,000 of turnover and £40,000 of profit pays tax on the £40,000, at 19%.