Use our corporation tax calculator to estimate your tax liability based on your limited company’s taxable profit. Get a clear view of how much Corporation Tax your company may owe for the 2025/26 or 2026/27 tax year.
Prefer working offline? Download our free Excel version of this calculator and run your calculations anytime.
Estimate Corporation Tax due, marginal relief, adjusted thresholds, payment timing and a sensible monthly tax reserve for your limited company. 2025/26 is included for prior-year planning because the core non-ring fence rates remain the same.
Taxable Profit: £0
Tax Year: 2026/27
Augmented Profits Used: £0
Adjusted Small Profits Limit: £50,000
Adjusted Main Rate Limit: £250,000
Tax Band: -
Corporation Tax Before Relief: £0
Marginal Relief Reduction: £0
Corporation Tax Due: £0
Profit After Corporation Tax: £0
Effective Corporation Tax Rate: 0%
Estimated Payment Due Date: Not entered
Payment Basis: Standard
Suggested Monthly Tax Reserve: £0
These assumptions explain how this Corporation Tax estimate has been calculated.
The calculator uses the standard UK Corporation Tax small profits rate of 19% and main rate of 25%.
The standard limits are £50,000 for the small profits rate and £250,000 for the main rate. These limits may be reduced where the company has associated companies or a short accounting period.
The associated-company field is treated as the total number of companies sharing the Corporation Tax limits, including the company being calculated.
Where profits fall between the adjusted lower and upper limits, the calculator applies marginal relief using the standard 3/200ths fraction.
Where non-group dividend income is entered, it is used for marginal relief and threshold testing. Corporation Tax itself is still estimated on taxable profits.
If an accounting period end date is entered, the estimated payment date is calculated as 9 months and 1 day after the end of the accounting period.
The monthly reserve figure is a planning estimate only. It spreads the estimated tax due across the available months until the expected payment deadline.
This estimate does not include R&D relief, losses, capital allowance adjustments, group relief, ring fence profits, overseas tax, specialist reliefs, or accountant-specific year-end adjustments.
Corporation Tax is a tax placed on the profits of a company. If you operate a limited company, whether in IT contracting or another industry, you are required to pay tax on your company’s taxable profits. The amount of Corporation Tax you owe depends on how much profit your company makes in a given accounting period.
For most businesses, the standard Corporation Tax rules apply. However, the UK tax system includes a small profits rate, a main rate and marginal relief for companies with profits between the lower and upper limits. This is where our Corporation Tax Calculator helps — it allows you to estimate your Corporation Tax quickly and understand how much your company may need to pay.
Corporation Tax in the UK is based on the taxable profits your company earns. For the 2025/26 and 2026/27 tax years, the following rates apply:
This calculator gives a reliable estimate based on current UK Corporation Tax rates, including marginal relief. It is ideal for planning and decision-making, but your final liability may differ depending on allowances, timing, losses, reliefs, investment income, associated companies and your accountant’s adjustments.
Yes. If your profits fall between the relevant lower and upper limits, marginal relief is automatically applied. The calculator can also adjust the limits for associated companies and short accounting periods where you enter the relevant details.
You should deduct allowable business expenses first. This may include software, subscriptions, equipment, insurance, accountancy fees, travel, training and relevant home office costs. Entering taxable profit after expenses gives a more accurate tax estimate.
Leaving profits in your company can delay personal tax such as dividend tax if you do not need the funds immediately. However, this should be considered alongside cashflow, pension planning, future income needs and your wider tax position.
You may be able to reduce Corporation Tax by claiming all allowable expenses, making employer pension contributions, using capital allowances, planning the timing of income and purchases, and reviewing available reliefs with your accountant.
Corporation Tax is typically due nine months and one day after the end of your company’s accounting period. If your company is large or very large for Corporation Tax purposes, instalment payment rules may apply instead.