Tax calculators
UK Corporation Tax Calculator
Work out your company's Corporation Tax, including the small profits rate, the main rate and Marginal Relief, with adjustments for associated companies and short accounting periods.
Estimated Corporation Tax
£22,750
on £100,000 of taxable profit
Effective rate: 22.75%
Summary
- Taxable profit
- £100,000
- Corporation Tax before relief
- £25,000.00
- Marginal Relief
- -£2,250.00
- Estimated Corporation Tax
- £22,750.00
- Effective tax rate
- 22.75%
- Profit after Corporation Tax
- £77,250.00
- Days in accounting period
- 365
Financial year apportionment
| Financial year | Days | Profit | Tax |
|---|---|---|---|
| FY2026main rate with Marginal Relief · limits £50,000–£250,000 | 365 | £100,000 | £22,750.00 |
These calculations are estimates based on the information entered and the tax rates and assumptions shown. They are intended as a general guide and do not constitute tax advice. Your actual tax position may differ depending on your circumstances, reliefs, other income and applicable tax rules.
About this tool
What the Corporation Tax calculator does
Since April 2023 Corporation Tax has not been a single percentage. Companies with small profits pay the small profits rate, companies with large profits pay the main rate, and companies in between pay the main rate reduced by Marginal Relief. This calculator handles all three cases properly rather than applying one rate to everything.
It also deals with the situations that catch companies out: an accounting period that straddles 1 April, a short first or final period, and the effect of associated companies on the Marginal Relief limits.
Method
How the calculation works
The accounting period is split into slices by financial year. Profits are apportioned across those slices by the number of days, and each slice is taxed under that financial year's rates.
For financial year 2026, the small profits rate is 19% up to £50,000 of augmented profits, the main rate is 25% above £250,000, and Marginal Relief applies in between using the standard fraction of 3/200.
Marginal Relief is calculated as F × (U − A) × (N ÷ A), where F is the standard fraction, U is the upper limit, A is augmented profits — taxable profits plus exempt distributions from unassociated companies — and N is taxable total profits.
Both limits are reduced pro rata for a short accounting period, and divided by the number of associated companies plus one.
Worked example
£100,000 of profit in a 12-month period
A company with taxable profits of £100,000, no associated companies and no distributions received falls between the £50,000 lower limit and the £250,000 upper limit, so the main rate applies with Marginal Relief.
Tax at the main rate of 25% is £25,000. Marginal Relief is 3/200 × (£250,000 − £100,000) × (£100,000 ÷ £100,000) = £2,250.
Corporation Tax is therefore £22,750, an effective rate of 22.75%, leaving £77,250 of post-tax profit available for reinvestment or distribution.
Assumptions
What this calculator assumes
It assumes the figure you enter is taxable total profits, that the company is not a close investment holding company (which pays the main rate regardless of profit), and that no reliefs such as R&D, group relief, losses brought forward or the Patent Box apply. It does not calculate quarterly instalment payments for large companies.
Once you know the tax, the next question is usually what to do with the profit. Our director salary and dividend calculator covers extraction, and our Corporation Tax and tax planning services cover the rest.
Rates and assumptions
What this calculator uses
- Tax year shown
- 2026/27
- Geographical scope
- England, Wales and Northern Ireland
- Rates last reviewed
- 19 September 2026
- Source of rates
- HMRC / GOV.UK
Official guidance
- Corporation Tax rates and allowances (GOV.UK)
- Marginal Relief for Corporation Tax (GOV.UK)
- Associated companies (GOV.UK)
- Pay your Corporation Tax bill (GOV.UK)
These calculations are estimates based on the information entered and the tax rates and assumptions shown. They are intended as a general guide and do not constitute tax advice. Your actual tax position may differ depending on your circumstances, reliefs, other income and applicable tax rules.
Questions
Common questions
Marginal Relief smooths the jump between the small profits rate and the main rate. Between the lower and upper limits, tax is charged at the main rate and then reduced by a formula, which produces an effective marginal rate of 26.5% on profits in that band.
Need help reducing or planning your Corporation Tax?
From capital allowances and timing to how profits are extracted, we help limited companies in Scunthorpe plan their tax rather than just report it.
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Services that work alongside this
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- Explore tax planning
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