The Corporation Tax Calculator is an essential tool for UK businesses to calculate their corporation tax liability, including marginal relief for profits between £50,000 and £250,000. Companies of all sizes need this tool to ensure accurate tax planning and compliance with HMRC regulations.
How Corporation Tax Calculator works in 2026
In 2026, the corporation tax rate in the UK is set at 25% for profits over £250,000. However, businesses with profits between £50,000 and £250,000 can benefit from marginal relief, which reduces their tax rate progressively. This relief is calculated based on a sliding scale, effectively lowering the tax rate from 25% to 19% as profits decrease within this range. HMRC provides detailed guidelines on calculating marginal relief to ensure businesses receive the correct tax benefits.
To calculate corporation tax with marginal relief, one must first determine their taxable profits. This involves deducting allowable expenses from total revenue, as per HMRC guidelines. Once the taxable profits are known, the Corporation Tax Calculator applies the appropriate rate and marginal relief to compute the tax due. Companies House requires businesses to report these figures accurately in their annual returns.
When to use Corporation Tax Calculator
This tool is particularly useful in the following scenarios:
- Scenario 1: A small business with profits of £75,000 looking to calculate their marginal relief.
- Scenario 2: A medium enterprise with fluctuating profits needing to plan for tax liabilities within the £50,000 to £250,000 range.
- Scenario 3: An accountant preparing tax returns for multiple clients with varying profit levels.
- Scenario 4: A new company estimating their first-year tax obligations based on projected profits.
Key UK rates / thresholds for 2026
These are the corporation tax rates and thresholds for 2026:
| What | Rate / threshold | Notes |
|---|---|---|
| Corporation Tax Rate | 25% | Applicable to profits over £250,000 |
| Marginal Relief Start | £50,000 | Start of marginal relief |
| Marginal Relief End | £250,000 | Threshold for full 25% rate |
| Small Profits Rate | 19% | For profits up to £50,000 |
Worked example
Consider a UK business, Widget Ltd, with a taxable profit of £150,000 in 2026. First, calculate the full corporation tax at 25%: £150,000 x 25% = £37,500. Next, compute the marginal relief. The formula for marginal relief is £(250,000 - profit) x (tax rate difference) / 200,000. For Widget Ltd, this is £(250,000 - 150,000) x (25% - 19%) / 200,000 = £6,000. Therefore, the final corporation tax payable is £37,500 - £6,000 = £31,500.
Common mistakes
- Incorrectly calculating taxable profits. Ensure all allowable expenses are deducted as per HMRC guidelines.
- Not applying marginal relief correctly. Use the calculator to ensure accurate relief is applied.
- Missing deadlines for tax returns. Submit corporation tax returns to Companies House on time to avoid penalties.
- Failing to update profit projections. Regularly review and adjust profit estimates to accurately plan tax payments.
Related calculations
Businesses often need to calculate VAT liabilities alongside corporation tax. Additionally, calculating PAYE for employees and self-assessment tax returns for directors can be necessary. These calculations help provide a complete picture of a business's tax obligations.
What HMRC checks
HMRC requires businesses to retain financial records for at least six years. This includes all income, expenses, and calculations pertaining to corporation tax. Ensure records are detailed and accessible, as discrepancies can trigger investigations. Regular audits and reconciliations help maintain compliance.
Bottom line
The Corporation Tax Calculator is a vital tool for UK businesses to accurately determine their tax obligations, particularly with marginal relief in play. By following HMRC guidelines and using this tool, businesses can ensure compliance and avoid costly errors. Regular use of the calculator aids in effective financial planning and management.