Corporation Tax Calculator UK 2026/27

For limited companies — calculate your Corporation Tax bill including marginal relief

✓ Updated 2026/27✓ No signup✓ No data stored✓ Runs in your browser
£
CORPORATION TAX DUE
£0
for the year
Effective Rate
0%
Marginal Relief
£0
Profit After Tax
£0
Which Band

Corporation Tax rates 2026/27

Profit bandRate
Up to £50,00019% (Small Profits Rate)
£50,001 – £250,000Marginal Relief (effective 19%–25%)
Over £250,00025% (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 rate19.4%

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:

Marginal Relief = (£250,000 − Profit) × (Profit ÷ Profit) × 3/200
  1. Calculate tax at the main rate (25%) on the full profit
  2. Calculate Marginal Relief using the standard fraction (3/200)
  3. Subtract the relief from the main rate tax to get your final bill
  4. If you have associated companies, the £50,000 and £250,000 thresholds are divided by the number of associated companies

Frequently asked questions

What is the Corporation Tax rate for 2026/27?

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%.

What is Marginal Relief?

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.

Do associated companies affect my Corporation Tax?

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.

When is Corporation Tax due?

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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🔒 Privacy & disclaimer

All calculations run entirely in your browser. No data is sent to our servers, stored, or shared with any third party.

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.