Corporation Tax Calculator UK 2026/27
Estimate your UK limited company’s Corporation Tax, marginal relief, effective tax rate and profit after tax. The calculation adjusts the £50,000 and £250,000 thresholds for associated companies and short accounting periods.
Enter your company figures
Use figures for one Corporation Tax accounting period.
The standard rates and thresholds are the same in both years.
Use taxable profit after allowable expenses, capital allowances and reliefs, but before Corporation Tax.
Usually qualifying exempt distributions from companies outside a 51% group. These increase augmented profits.
Do not include the company being calculated. Enter 0 if there are no others.
Accounting period and eligibility
Short periods reduce the marginal-relief thresholds. A CT accounting period cannot exceed 12 months.
Used to estimate the normal payment deadline of 9 months and 1 day.
Non-UK resident companies and close investment-holding companies cannot claim marginal relief. Specialist ring-fence regimes are not modelled.
Planning estimate only. Your CT600 computation may include losses, group relief, R&D relief, capital allowances, tax credits or specialist rules not modelled here.
Your estimated Corporation Tax
Based on the figures entered.
Estimated Corporation Tax
£16,125.00
Marginal relief applies
| Taxable total profits | £75,000.00 |
|---|---|
| Relevant exempt distributions | £0.00 |
| Augmented profits | £75,000.00 |
| Tax at 25% before relief | £18,750.00 |
| Less marginal relief | − £2,625.00 |
| Estimated Corporation Tax | £16,125.00 |
Marginal relief reduces tax charged at the 25% main rate. The calculation uses (3/200 × (upper limit − augmented profits)) × (taxable profits ÷ augmented profits).
Quick answer
UK Corporation Tax rates for 2026/27
For the financial year beginning 1 April 2026, a qualifying company generally pays 19% where augmented profits do not exceed the lower limit, 25% where they exceed the upper limit, and 25% less marginal relief between the limits. The limits are adjusted for short periods and associated companies.
Normally applies where augmented profits are no more than £50,000 for a full 12-month period with no associated companies.
The company is charged at 25%, then marginal relief reduces the bill. The effective rate rises gradually across the range.
Normally applies where augmented profits exceed £250,000, or when the company is not eligible for the small-profits regime.
Methodology
How this Corporation Tax calculator works
The tool follows HMRC’s current non-ring-fence rate structure. It asks for taxable total profits separately from relevant exempt distributions because marginal relief uses augmented profits, not accounting profit alone.
Taxable profit is not turnover
Turnover is the company’s sales before costs. Taxable total profits are broadly the profits and chargeable gains left after allowable business expenses, capital allowances and relevant reliefs. Use the taxable figure from a tax computation where possible. If you only have bookkeeping profit, the result is a rough budget rather than a filing figure.
What are augmented profits?
For this calculation, augmented profits are taxable total profits plus relevant exempt distributions. Those distributions can move a company into the marginal-relief range or main rate even though they are not themselves included in taxable total profits.
Why associated companies matter
The standard £50,000 and £250,000 limits are divided by the total number of associated companies, including the company being calculated. If there are three other associated companies, both limits are divided by four. Control, connected parties and commercial interdependence can make this more complex than simply counting companies with the same director.
Calculation steps
| Financial year | Small-profits rate | Lower limit | Upper limit | Main rate | Marginal fraction |
|---|---|---|---|---|---|
| 2026/27 — current | 19% | £50,000 | £250,000 | 25% | 3/200 |
| 2025/26 — previous | 19% | £50,000 | £250,000 | 25% | 3/200 |
Worked example: £75,000 taxable profit
A standard UK trading company with a 12-month period, no associated companies and no relevant exempt distributions is charged £18,750 at 25%. Marginal relief of £2,625 reduces the estimated Corporation Tax to £16,125.
Use the estimate correctly
What the calculator includes—and what needs a tax computation
A reliable estimate should be transparent about its limits. This calculator works from taxable total profits; it does not try to turn raw turnover and expenses into a complete CT600 calculation.
Included in this estimate
- 2025/26 and 2026/27 non-ring-fence rates.
- Small-profits rate and 25% main rate.
- HMRC marginal-relief formula using augmented profits.
- Associated-company and short-period threshold adjustments.
- Estimated normal payment date when a period end is supplied.
Not calculated automatically
- Trading losses, group relief and carried-forward losses.
- Capital allowances, R&D relief, Patent Box and tax credits.
- Close-company loans, quarterly instalments and interest.
- Ring-fence, non-resident and close investment-holding company rules.
- Whether accounting profit is correctly adjusted to taxable profit.
Next step
Turn the estimate into a company-tax decision
The bill is only one part of the decision. Use the relevant route below to check profit extraction, director loans, reliefs or year-end filing.
Corporation Tax questions
Answers for UK limited companies
What is the UK Corporation Tax rate for 2026/27?
For non-ring-fence profits in the financial year from 1 April 2026 to 31 March 2027, the main Corporation Tax rate is 25% and the small-profits rate is 19%. Marginal relief may reduce the bill where a qualifying company’s augmented profits fall between the adjusted lower and upper limits.
How much Corporation Tax is due on £50,000 profit?
A qualifying UK trading company with a full 12-month period, no associated companies and no relevant exempt distributions would normally pay £9,500, which is 19% of £50,000. A short period, associated companies, exempt distributions or ineligibility for the small-profits rate can change the result.
How much Corporation Tax is due on £100,000 profit?
Under the same standard assumptions—12 months, no associated companies or relevant exempt distributions, and eligibility for marginal relief—Corporation Tax on £100,000 is approximately £22,750. This is £25,000 at the main rate less £2,250 marginal relief, giving an effective rate of 22.75%.
How is Corporation Tax marginal relief calculated?
The current formula is (3/200 × (upper limit − augmented profits)) × (taxable total profits ÷ augmented profits). The relief is deducted from tax charged at the 25% main rate. The upper limit must first be adjusted for the period length and number of associated companies.
What counts as an associated company?
Broadly, companies are associated when one controls the other or both are under common control. Connected-person rights and substantial commercial interdependence can affect the test, while some passive companies may be excluded. Because the answer changes the tax thresholds, obtain advice where ownership or control is shared.
Does a short accounting period change the Corporation Tax thresholds?
Yes. The £50,000 and £250,000 limits are proportionately reduced when the Corporation Tax accounting period is shorter than 12 months. They are then divided by the number of associated companies including the company being calculated. Enter the period days and other associated companies above to model both adjustments.
When is Corporation Tax due?
For a company with taxable profits up to £1.5 million, Corporation Tax is normally due nine months and one day after the end of the accounting period. The Company Tax Return is normally due 12 months after the period ends. Larger companies may have to pay by instalments earlier.
Is Corporation Tax calculated on turnover or profit?
Corporation Tax is charged on taxable profits, not turnover. Taxable profits can include trading profits, investment income and chargeable gains after allowable deductions and reliefs. Accounting profit may need tax adjustments, so do not enter sales revenue unless it is also the correctly calculated taxable-profit figure.
Does this calculator include R&D relief or capital allowances?
Not as separate inputs. Both can affect taxable total profits, so include their effect before entering the final taxable-profit figure. R&D rules depend on the accounting period, claim conditions and applicable scheme; a simple percentage field can produce a misleading filing estimate. See our R&D tax relief guide.
Do sole traders pay Corporation Tax?
No. Sole traders generally pay Income Tax and National Insurance on self-employed profits rather than Corporation Tax. A limited company is a separate legal entity and may pay Corporation Tax on its taxable profits. Compare the structures in our sole trader vs limited company guide.
- HMRC Corporation Tax rates and allowances
- HMRC marginal relief guidance
- HMRC Company Tax Return deadlines
Rates and content checked 4 August 2026. Review again after a fiscal statement affecting Corporation Tax and before 1 April 2027.
Need the filing figure, not just an estimate?
Path Accountants can review the taxable-profit adjustments, associated-company position, reliefs and deadline. We support London businesses online and through our Wembley office.