Estimate UK Corporation Tax using the small profits rate, main rate and marginal relief band. Enter taxable profits to see the effective corporation tax rate and the tax due. This …
Corporation Tax
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Effective rate
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Marginal relief
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About this calculator
Estimate UK Corporation Tax using the small profits rate, main rate and marginal relief band. Enter taxable profits to see the effective corporation tax rate and the tax due. This is useful for owner‑managed companies where profits may sit inside the marginal relief range and the effective rate changes as profits rise.
How the calculation works
We apply the small profits rate below the lower threshold, the main rate above the upper threshold, and marginal relief in the band between. The result is shown as tax due and an effective rate.
FAQ
What is marginal relief?
A mechanism that gradually increases the effective corporation tax rate between the small profits and main rates.
Does associated companies affect thresholds?
Yes. Thresholds can be divided by the number of associated companies.
Is this for financial years?
Corporation Tax is based on accounting periods; rate changes can require pro‑rating.
Does it include reliefs?
No. This is a profit‑to‑tax estimate before specific reliefs and adjustments.
This tool estimates UK corporation tax on annual taxable profits using a simplified banded model. It’s useful for planning profit extraction and comparing scenarios across the suite.
Taxable profit is the starting point (after allowable deductions).
A simplified band structure is applied (planning estimate).
Results are deterministic and intended for scenario comparison.
Next steps
If you extract profits, pair this with Salary vs Dividend to see the end-to-end impact.
Is this calculator “exact”? It’s deterministic using stated assumptions, but it won’t cover every edge case (e.g., special reliefs). Use it for planning and compare with official guidance for edge cases.
Why do results change sharply at thresholds? Most UK taxes/charges are banded. Crossing a band can change the marginal rate applied to the next slice, which can look like a step-change in totals.