Corporation Tax Calculator UK 2026
Use our UK Corporation Tax Calculator to estimate how much Corporation Tax your limited company may owe based on taxable profits. The calculator uses the current 19% small profits rate, 25% main rate and Marginal Relief rules for profits between the relevant thresholds.
Based on HMRC’s official rules for Corporation Tax rates and Marginal Relief. See GOV.UK guidance on Corporation Tax rates and Marginal Relief for further details.
Calculate Your UK Corporation Tax
Important: This calculator provides an indicative estimate only. It assumes a 12-month accounting period, no associated companies and no relevant distributions affecting augmented profits. Different rules may apply to short accounting periods, associated companies, close investment holding companies and ring fence profits.
If you need help understanding your calculation, Marginal Relief, allowable expenses or wider Corporation Tax position, our Corporation Tax accountants can provide practical support.
Corporation Tax: What It Is, Why Compliance Matters, and How a Corporation Tax Calculator Helps
Corporation tax is the tax that UK limited companies and certain organisations pay on their taxable profits. It covers trading income, investment returns, and chargeable gains, after deducting allowable expenses, capital allowances, and any reliefs. Companies file returns on a CT600 for each accounting period.
Staying compliant matters because timely, accurate returns and payments protect your business from HMRC penalties and interest. Good compliance also reduces the risk of intrusive enquiries and preserves access to valuable reliefs such as loss offsets, R&D, and capital allowances. It strengthens cash-flow forecasting and dividend planning, and it signals reliability to lenders, investors, suppliers, and customers.
Strong tax processes improve management information and board decision-making. They encourage disciplined reviews of revenue recognition, director remuneration, intercompany recharges, and balance-sheet provisions.
In practice, using a corporation tax calculator alongside robust bookkeeping helps you estimate liabilities early. You can model scenarios rate changes, marginal relief thresholds, asset purchases, or loss carry-backs so you set aside the right cash and avoid year-end surprises. Tie those estimates to your finance calendar to ensure payments are made on time, including quarterly instalments for large companies, and support the return with clear working papers.
Ultimately, corporation tax compliance is not just a statutory obligation; it is a foundation for sustainable growth. If you need help reviewing your calculation, marginal relief position, associated companies or available Corporation Tax reliefs, speak to our Corporation Tax accountants. It supports better valuations and smoother due diligence. It enables owners to reinvest with confidence, reward teams responsibly, and demonstrate sound governance. Combined with proactive advice from qualified accountants and the regular use of a corporation tax calculator, it turns tax from a once-a-year scramble into a predictable, well-managed business process.
Important note: Our calculators provide indicative estimates only and may not be 100% accurate. Before making any financial or tax decisions, please consult a qualified, certified accountant, online calculators do not constitute advice.