Corporation Tax Calculator
Estimate Corporation Tax before it becomes a cash flow surprise.
Use this calculator to estimate Corporation Tax on company profits using the small profits rate, main rate and Marginal Relief approach for non-ring fence companies.
19% small profits rate
25% main rate
Marginal Relief estimate
Guidance before action
What this tool helps with
Use it to estimate company tax pressure.
This calculator helps limited company owners get an early estimate of Corporation Tax before year-end or payment deadlines.
Corporation Tax calculator
Estimate your company’s Corporation Tax.
Enter taxable profit, associated companies and whether you want to apply Marginal Relief where relevant.
Your calculation
This calculator is for simple non-ring fence company profit estimates. It does not replace a full CT600, tax computation or professional Corporation Tax review.
Your result
Based on taxable company profit of £100,000.
Estimated Corporation Tax
£22,250.00
Taxable profit
£100,000.00
Effective tax rate
22.25%
Base tax before relief
£25,000.00
Marginal Relief
£2,750.00
Adjusted lower limit
£50,000.00
Adjusted upper limit
£250,000.00
This is a general estimate only. Associated companies, accounting periods, reliefs, losses, deductions and company circumstances can affect the final Corporation Tax position.
Important Corporation Tax guidance
This calculator uses the 2026 non-ring fence Corporation Tax bands: 19% small profits rate, 25% main rate, lower limit £50,000, upper limit £250,000 and standard Marginal Relief fraction 3/200. The limits may need adjusting for associated companies and shorter accounting periods. This is a planning estimate, not Corporation Tax advice.
If profits are below the lower limit
Companies with profits at or below the adjusted lower limit are generally estimated using the small profits rate. For a standard 12-month period with one company, the lower limit is £50,000.
If profits fall between the limits
Companies between the adjusted lower and upper limits may pay tax at the main rate reduced by Marginal Relief. This creates a gradual increase in the effective Corporation Tax rate.
Related tools
Useful company tax tools to try next.
Want a Corporation Tax planning checklist?
Use the calculator for a quick estimate, then use a checklist to think through tax planning, payment timing, bookkeeping, profit extraction and year-end preparation.
Corporation Tax is a cash flow issue too.
Estimating tax early helps company owners plan cash flow, dividends, drawings and year-end decisions more calmly.
Corporation Tax Calculator FAQs
Quick questions before using the calculator.
No. This is a simple estimator. A proper Corporation Tax computation may include allowances, losses, disallowable costs, capital allowances, associated companies and other adjustments.
Associated companies can affect the Corporation Tax limits. If your company is connected with other companies, the thresholds may need to be divided between them.
No. You should enter the taxable profit figure after relevant adjustments. The calculator does not work out capital allowances, losses or disallowed expenses.
Yes. BondEsq can review your company profit, bookkeeping, tax planning, year-end position and Corporation Tax filing requirements.
Need help planning around Corporation Tax?
The calculator gives a useful estimate. A proper conversation helps you understand how tax connects to profit, cash flow, dividends, bookkeeping, year-end planning and business decisions.
Use the calculator wisely
Estimate the tax, then understand what it means for the business.
Corporation Tax affects cash flow, director pay planning, profit extraction and year-end decisions. Use this as a starting point before acting.