Corporation Tax Calculator UK 2026/27
For limited companies — calculate your Corporation Tax bill including marginal relief
Corporation Tax rates 2026/27
| Profit band | Rate |
|---|---|
| Up to £50,000 | 19% (Small Profits Rate) |
| £50,001 – £250,000 | Marginal Relief (effective 19%–25%) |
| Over £250,000 | 25% (Main Rate) |
Worked example
A company with £100,000 taxable profit falls in the marginal relief band:
| Taxable profit | £100,000.00 |
| Tax at main rate (25%) | £25,000.00 |
| Marginal Relief deduction | −£5,625.00 |
| Corporation Tax due | £19,375.00 |
| Effective tax rate | 19.4% |
How marginal relief is calculated
Marginal Relief smooths the jump from 19% to 25% for profits between £50,000 and £250,000, using this formula:
- Calculate tax at the main rate (25%) on the full profit
- Calculate Marginal Relief using the standard fraction (3/200)
- Subtract the relief from the main rate tax to get your final bill
- If you have associated companies, the £50,000 and £250,000 thresholds are divided by the number of associated companies
Frequently asked questions
The Small Profits Rate is 19% for profits up to £50,000. The Main Rate is 25% for profits over £250,000. Profits between these thresholds benefit from Marginal Relief, giving an effective rate between 19% and 25%.
Marginal Relief reduces the Corporation Tax bill for companies with profits between £50,000 and £250,000, smoothing the transition from the 19% Small Profits Rate to the 25% Main Rate rather than a sudden jump.
Yes. If you have associated companies (companies under common control), the £50,000 and £250,000 thresholds are divided by the total number of associated companies, which can push you into a higher effective rate sooner.
Corporation Tax is due 9 months and 1 day after the end of your accounting period. Companies with profits over £1.5 million pay in quarterly instalments instead.
📄 HMRC sources
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Results are estimates based on 2026/27 HMRC rates and are intended as a guide only. They do not constitute financial or tax advice. Always verify with HMRC or a qualified accountant for your specific circumstances.