Corporation Tax Calculator

UK Business Tax Estimate

UK Corporation Tax Calculator 2026

Estimate the Corporation Tax payable by a UK limited company using the 19% small profits rate, the 25% main rate and Marginal Relief where applicable.

Small profits rate 19%

Normally applies when augmented profits do not exceed the adjusted lower limit.

Marginal Relief £50k–£250k

A tapered tax calculation may apply between the adjusted profit limits.

Main Corporation Tax rate 25%

Normally applies when augmented profits exceed the adjusted upper limit.

Enter the Company’s Details

The profit limits are automatically adjusted for associated companies and accounting periods shorter than 12 months.

Enter taxable profits after allowable business expenses and tax adjustments.
Include relevant exempt distributions used to calculate augmented profits.
Exclude the company being calculated. Enter zero when there are none.
Enter the number of days, up to 365, in the Corporation Tax accounting period.
An indicative monthly amount that could be reserved for the estimated bill.
Marginal Relief

Estimated Corporation Tax

£22,750

This estimate uses the Marginal Relief calculation because augmented profits fall between the adjusted lower and upper limits.

Effective tax rate 22.75%
Profit after Corporation Tax £77,250
Marginal Relief deducted £2,250
Suggested monthly reserve £1,896
Adjusted lower limit £50,000
Adjusted upper limit £250,000
Effective rate 22.75% of taxable profits

Your Corporation Tax Answer

On taxable profits of £100,000, the estimated Corporation Tax liability is £22,750. This leaves approximately £77,250 after Corporation Tax.

How Is UK Corporation Tax Calculated in 2026?

A company with augmented profits at or below the adjusted lower limit will normally pay Corporation Tax at the 19% small profits rate.

The 25% main rate normally applies when augmented profits exceed the adjusted upper limit. Marginal Relief may reduce the tax bill when augmented profits fall between the two limits.

Marginal Relief = (Upper limit − augmented profits) × (taxable profits ÷ augmented profits) × 3 ÷ 200

What Are Augmented Profits?

Augmented profits generally include taxable total profits plus certain exempt distributions received by the company.

Augmented profits help determine which Corporation Tax rate applies. The tax itself is calculated on taxable total profits rather than on the exempt distributions.

Augmented profits = taxable total profits + relevant exempt distributions

How Do Associated Companies Affect the Limits?

The standard £50,000 and £250,000 limits are divided by the total number of associated companies, including the company being calculated.

For example, where a company has one associated company, the standard limits are normally divided by two.

  • No associated companies: £50,000 and £250,000 limits
  • One associated company: £25,000 and £125,000 limits
  • Three associated companies: £12,500 and £62,500 limits

What Is Not Included in This Estimate?

The calculator provides a simplified estimate for an ordinary UK company. It does not calculate every relief, allowance, surcharge or specialist Corporation Tax rule.

  • Capital allowances and Annual Investment Allowance claims
  • Trading losses carried forward or carried back
  • Research and development tax relief
  • Patent Box relief
  • Banking company surcharges
  • Ring Fence Corporation Tax
  • Quarterly instalment payment rules for large companies
Disclaimer: This Corporation Tax calculator provides an illustrative estimate based on the figures entered and the standard UK Corporation Tax framework. It is not accounting, tax, legal or financial advice. Actual liability may differ because of allowances, losses, reliefs, associated-company rules, distributions and other tax adjustments. A qualified accountant or tax adviser should review the company’s specific circumstances before a Corporation Tax return is submitted.

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