Corporation Tax calculator
Estimate your limited company’s Corporation Tax on its profit, including marginal relief between £50,000 and £250,000. 2025/26.
Assumes a single company with no associated companies and a 12-month accounting period. Associated companies and a short period change the thresholds — we’ll handle that for you.
In plain English
The terms, explained
New to this? Here’s what the words on this page actually mean.
- Corporation Tax
- The tax a limited company pays on its profits.
- Taxable profit
- Your profit after allowable business expenses — the figure the tax is based on.
- Marginal relief
- A sliding scale between £50,000 and £250,000 of profit, so the rate eases up gradually instead of jumping straight to 25%.
- Effective rate
- The actual percentage of your profit that goes in tax, once the rates and relief are applied.
FAQ
Corporation Tax calculator — your questions answered
How do I calculate Corporation Tax?
Apply the rate to your taxable profit: 19% up to £50,000, 25% over £250,000, and a tapered “marginal relief” rate in between. So most small companies pay somewhere between 19% and 25%. Our calculator works the taper out for you.
How much Corporation Tax will I pay on £100,000 profit?
For 2025/26, around £22,750 — that’s the 25% main rate reduced by marginal relief, giving an effective rate of roughly 22.75%. Enter your own profit above for an instant estimate.
Is Corporation Tax 25% now?
Only on profits above £250,000. Below £50,000 the rate is 19%, and between the two a sliding marginal-relief rate applies — so the headline 25% only affects larger companies.
Is Corporation Tax based on turnover or profit?
On profit — your income after allowable business expenses — not turnover. The simplest way to reduce it is to make sure every allowable cost is claimed.
How can I reduce my Corporation Tax?
Claim all allowable expenses, capital allowances on equipment, employer pension contributions, and reliefs such as R&D tax credits where you qualify. Planning these properly is exactly what we do for our limited-company clients.
When is Corporation Tax due?
Payment is due nine months and one day after your accounting period ends — earlier than the return itself, which is due 12 months after the period end. We track both deadlines for you.
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