UK Corporation Tax calculator 2026/27
Estimate Corporation Tax at 19% to 25%, including marginal relief and associated-company thresholds.
How the Corporation Tax estimate works
The estimate applies the small-profits rate, main rate or HMRC marginal-relief formula to taxable total profits. It adjusts the profit limits for associated companies and accounting periods shorter than 12 months.
Rules checked
Read the checking method
What the result includes
- 19% and 25% Corporation Tax regimes
- Marginal relief using augmented profits
- Adjusted limits for associated companies and short periods
What to have ready
- Taxable total profit for the accounting period
- Qualifying exempt distributions used in augmented profits
- Associated companies and exact accounting-period length
Questions about Corporation Tax
Is accounting profit the same as taxable profit?
Not necessarily. Capital allowances, disallowable expenses, losses and other tax adjustments can move the figure away from the profit in the accounts.
Why do associated companies matter?
The lower and upper profit limits are divided by the number of associated companies, including the company being calculated.
About this estimate
The calculator models accounting-period length, qualifying exempt distributions in augmented profits and associated-company limits. Ring-fence activity, losses and other reliefs remain outside the estimate.