Corporation Tax Calculator 2026/27
Enter your company's taxable profit to see the Corporation Tax due, your effective rate and how marginal relief tapers the bill between £50,000 and £250,000.
Last updated 4 July 2026 · Written and reviewed by Mustafa Bilgic
Corporation tax calculator
Corporation Tax on company profit, 2026/27.
Estimate for a standard company, no ring-fence profits. Confirm on GOV.UK.
Corporation Tax rates for 2026/27
Limited companies pay Corporation Tax on their profits. Since April 2023 there have been two rates: the small profits rate of 19% on profits up to £50,000, and the main rate of 25% on profits of £250,000 or more. Between those two figures, marginal relief tapers the bill so there's no sudden jump — the effective rate rises smoothly from 19% towards 25% as profits grow. Both rates and thresholds are unchanged for 2026/27.
A company with £100,000 profit pays 25% (£25,000) minus marginal relief of £2,250, giving £22,750 — an effective rate of 22.75%. A company with £40,000 profit pays a flat 19% (£7,600), and one with £300,000 pays a flat 25% (£75,000).
How marginal relief works
Marginal relief reduces the main-rate charge for profits between £50,000 and £250,000. The formula is: take 25% of the profit, then subtract (£250,000 − profit) × 3 ÷ 200. That standard fraction of 3/200 is what produces an effective 26.5% marginal rate on each pound earned inside the band — higher than the 25% headline, because the relief is being clawed back as profits rise. It's the tax quirk that makes profit-extraction timing and pension contributions worth planning around year end.
| Profit | Corporation Tax | Effective rate |
|---|---|---|
| £30,000 | £5,700 | 19.0% |
| £50,000 | £9,500 | 19.0% |
| £100,000 | £22,750 | 22.75% |
| £150,000 | £36,750 | 24.5% |
| £250,000 | £62,500 | 25.0% |
Associated companies split the thresholds
If your company has associated companies — broadly, other companies under common control — the £50,000 and £250,000 thresholds are divided between them. Two associated companies each get a £25,000 lower limit and £125,000 upper limit, so profits reach the main rate far sooner. This calculator divides the limits by the total number of companies (yours plus associates) so the estimate reflects your group.
Salary, dividends and the bigger picture
Corporation Tax is only the first layer for an owner-managed company. Profits are taxed in the company, then again when you extract them as salary (deductible for the company but subject to income tax and NI) or dividends (paid from post-tax profit and taxed personally). Getting the mix right is the heart of director tax planning — our dividend tax calculator and dividend tax guide handle the personal side, and a pension contribution from the company can reduce taxable profit altogether.
When Corporation Tax is due
For most small companies, Corporation Tax must be paid nine months and one day after the end of your accounting period, with the CT600 return filed within twelve months. Large companies (profits over £1.5m) pay in quarterly instalments. Interest runs on late payments, so set the money aside as profit accrues rather than facing it all at once. Full rules and the current rates are on GOV.UK.
Frequently asked questions
What is the Corporation Tax rate for 2026/27?
There are two rates: 19% (the small profits rate) on profits up to £50,000, and 25% (the main rate) on profits of £250,000 or more. Between £50,000 and £250,000, marginal relief tapers the effective rate up from 19% towards 25%.
How much Corporation Tax will I pay on £100,000 profit?
£22,750. That's 25% of £100,000 (£25,000) minus marginal relief of £2,250, giving an effective rate of 22.75%. Enter your own profit above to see the exact figure for your company.
What is marginal relief on Corporation Tax?
Marginal relief reduces the 25% main-rate charge for profits between £50,000 and £250,000. It's calculated as (£250,000 minus your profit) times 3/200, subtracted from the 25% charge. It produces an effective 26.5% marginal rate on profits inside that band.
How do associated companies affect Corporation Tax?
The £50,000 and £250,000 thresholds are shared between associated companies under common control. If you have one associate, each company's lower limit becomes £25,000 and upper limit £125,000, so the main rate applies at lower profits.
When do I have to pay Corporation Tax?
Small companies pay nine months and one day after the end of their accounting period, and file the CT600 return within twelve months. Companies with profits over £1.5 million pay in quarterly instalments. Late payment attracts interest.