UK Corporation Tax Calculator (2025/26)
Estimate your Corporation Tax bill, including the marginal relief that applies between £50,000 and £250,000 of profit. UK-specific, current for the 2025/26 financial year.
UK Corporation Tax for the 2025/26 financial year is 19% on profits up to £50,000 (the small profits rate), 25% on profits of £250,000 or more, and a tapered effective rate in between via marginal relief. The thresholds are divided by the number of associated companies.
Marginal relief band. Profit is between £50,000 and £250,000.
How the calculation works
The UK Corporation Tax system since April 2023 uses two headline rates and marginal relief between them:
- Small profits rate (19%) — applies if augmented profits are at or below £50,000.
- Main rate (25%) — applies if augmented profits are at or above £250,000.
- Marginal relief — between £50,000 and £250,000, the main rate of 25% is reduced by a sliding amount, producing an effective rate that climbs from 19% to 25% as profits rise.
The marginal relief formula
Marginal relief = (Upper limit − Augmented profits) × (Augmented profits ÷ Taxable profits) × 3 ÷ 200.
Tax payable = (Taxable profits × 25%) − Marginal relief.
In simple cases (no associated companies, no overseas profits) augmented profits equal taxable profits, so the second fraction is 1.
Associated companies
If you control multiple UK limited companies, the £50,000 and £250,000 thresholds are divided by the total number of associated companies. Two associated companies share thresholds of £25,000 and £125,000 — so the marginal band kicks in earlier.
This calculator assumes no associated overseas profits, no R&D claim, no patent box, no group relief and no losses brought forward. For anything more complex, work with a UK chartered accountant.
Frequently asked questions
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Information on this page is general guidance for UK small businesses and is not financial, tax or legal advice. Tax rules, allowances and product terms change. Always check current information with HMRC, Companies House or a qualified professional before making decisions.