UK companies · standard non-ring-fence profits
Corporation Tax Calculator
Estimate Corporation Tax at the small profits rate, main rate or marginal-relief rate after adjusting the profit limits for the accounting period and associated companies.
Use taxable total profits after tax adjustments—not turnover or accounting profit before the tax computation. Add relevant exempt distributions separately because they can affect marginal relief.
Company tax estimate
Calculate the Corporation Tax liability
The company count must include the company being calculated. Use months only where the accounting period is shorter than twelve months.
- Taxable total profits
- £100,000.00
- Augmented profits
- £100,000.00
- Adjusted lower limit
- £50,000.00
- Adjusted upper limit
- £250,000.00
- Tax at main rate before relief
- £25,000.00
- Marginal relief
- £2,250.00
- Effective Corporation Tax rate
- 22.75%
- Profit after Corporation Tax
- £77,250.00
The effective rate rises gradually between the adjusted lower and upper limits.
Estimate only. A company tax computation can change for losses, capital allowances, group relief, loan relationships, chargeable gains and other adjustments.
Direct answer
Which Corporation Tax rate applies?
A company with augmented profits no higher than its adjusted lower limit normally uses the small profits rate. Above the adjusted upper limit it uses the main rate. Between the limits, tax at the main rate is reduced by marginal relief.
The £50,000 and £250,000 headline limits are reduced for short accounting periods and divided by the number of associated companies, so two companies under common control can reach marginal relief sooner than one standalone company.
Check Corporation Tax rates on GOV.UK →Calculation method
How marginal relief is calculated
The calculator follows the standard non-ring-fence computation and keeps taxable total profits separate from augmented profits.
Adjust the limits
Multiply each headline limit by accounting-period months divided by twelve, then divide by the associated-company count.
Establish augmented profits
Add relevant exempt distributions to taxable total profits for the rate-limit test.
Calculate main-rate tax
Taxable total profits are multiplied by the main Corporation Tax rate.
Deduct marginal relief
The relief uses the upper-limit gap, the standard fraction and the taxable-to-augmented profit fraction.
| Item | Unadjusted amount |
|---|---|
| Small profits rate | 19% |
| Main rate | 25% |
| Marginal-relief lower limit | £50,000 |
| Marginal-relief upper limit | £250,000 |
| Standard fraction | 3/200 |
Sources: Corporation Tax rates and allowances and HMRC marginal-relief guidance.
Before relying on the result
Taxable profit needs a company tax computation
Accounts profit is the starting point, not necessarily the taxable figure. Depreciation, capital allowances, entertaining, private expenditure, losses and connected-party transactions can all change the amount.
Included here
- small profits and main rates;
- marginal relief;
- short-period limit adjustment;
- associated-company limit adjustment;
- augmented profits.
Requires separate work
- straddling rate-change periods;
- ring-fence profits;
- R&D and patent box claims;
- loss and group-relief claims;
- close-company and loan charges.
Common questions
Corporation Tax calculator questions
What is an associated company?
Broadly, companies can be associated where one controls the other or both are under the control of the same person or persons. Commercial interdependence and attribution rules can matter, so the count should be checked rather than inferred from company names.
Why do exempt dividends affect marginal relief?
Relevant distributions can increase augmented profits used to test the limits and calculate relief even though they are not included in taxable total profits.
Does a loss-making company pay Corporation Tax?
A company with no taxable profit will not have Corporation Tax on ordinary profits for the period, but filing, loss claims and other charges may still need attention.
Does this calculate the payment deadline?
No. Most small companies pay nine months and one day after the accounting period ends, while large companies can fall within quarterly instalment rules.
Confidential enquiry
Need the Corporation Tax figure checked?
Tell us the accounting period, taxable-profit estimate and associated companies. Do not include authentication codes, bank details or a company UTR.