UK Corporation Tax Calculator

Calculate your company’s corporation tax liability for 2025/26

Include your company in this count (minimum 1 if you have associated companies)

Total Corporation Tax Due

£0

Tax Calculation Breakdown

What This Means

How Corporation Tax Works in the UK

Corporation tax is levied on the taxable profits of UK companies. All limited companies must pay corporation tax on their annual profits, regardless of where those profits were generated globally.

Current Corporation Tax Rates (2025/26)

Profit Band Tax Rate Description
£0 – £50,000 19% Small profits rate
£50,001 – £250,000 19% – 25% Marginal relief applies
Over £250,000 25% Main rate

Marginal Relief

Companies with profits between £50,000 and £250,000 may qualify for marginal relief, which provides a gradual transition between the 19% and 25% rates. The effective rate gradually increases from 19% to 25% as profits increase within this band.

Associated Companies

If your company has associated companies, the profit thresholds are divided by the total number of associated companies (including your own company). This can significantly affect your tax rate if you have multiple companies.

When to Pay

Corporation tax is typically due 9 months and 1 day after the end of your accounting period. Large companies (those with profits over £1.5 million) must pay quarterly instalments.

Step-by-Step Guide to Calculate Corporation Tax

Step 1: Determine Your Accounting Period

Your accounting period is usually the same as your company’s financial year. Most companies have a 12-month accounting period ending on 31 March.

Step 2: Calculate Taxable Profit

Start with your company’s net profit and make these adjustments:

  • Add back: Depreciation, entertaining costs, and other non-allowable expenses
  • Deduct: Capital allowances and other allowable deductions
  • Result: Your taxable profit for corporation tax purposes

Step 3: Apply the Correct Tax Rate

Use the profit bands and rates shown in the table above. Remember to adjust thresholds if you have associated companies.

Step 4: File Your Return

Complete and submit your Company Tax Return (CT600) along with your annual accounts to HMRC within 12 months of your accounting period end.

Frequently Asked Questions

What counts as taxable profit?
Taxable profit is your company’s net profit adjusted for tax purposes. This includes adding back depreciation and entertainment costs, then deducting capital allowances and other tax-allowable expenses.
How do I know if I have associated companies?
Companies are associated if one controls the other, or both are controlled by the same person or group of people. This includes companies controlled by the same director, shareholder, or family members.
When is corporation tax due?
Corporation tax is due 9 months and 1 day after the end of your accounting period. For example, if your accounting period ends on 31 March 2025, your tax is due by 1 January 2026.
What happens if I pay late?
HMRC charges interest on late payments and may impose penalties. The interest rate is set by HMRC and changes periodically. It’s important to pay on time to avoid additional costs.
Can I reduce my corporation tax bill?
Yes, through legitimate means such as claiming all allowable expenses, capital allowances, R&D tax credits, and pension contributions. Consider speaking with a qualified accountant for advice.

References

  • HM Revenue & Customs. (2025). Corporation Tax rates and reliefs. Available at: https://www.gov.uk/corporation-tax-rates
  • HM Revenue & Customs. (2025). Corporation Tax rates and allowances. Available at: https://www.gov.uk/government/publications/rates-and-allowances-corporation-tax
  • HM Revenue & Customs. (2025). Work out your Corporation Tax. Available at: https://www.gov.uk/corporation-tax
  • Companies House. (2025). Corporation Tax for limited companies. Available at: https://www.gov.uk/corporation-tax
  • Institute of Chartered Accountants in England and Wales. (2025). Corporation Tax Guide. London: ICAEW.

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