Corporation Tax calculator 2026/27
Work out your company's Corporation Tax, including marginal relief, associated companies and shorter accounting periods, with the dates it must be paid and filed. Every step of the working is shown.
More info
Your company's profit after allowable expenses and capital allowances, the figure Corporation Tax is charged on. If you are not sure, your accounts' profit before tax is a reasonable starting point.
More info
Companies are usually "associated" if one controls the other, or both are controlled by the same person or group of people. The £50,000 and £250,000 profit limits are shared between associated companies, so each one reaches the higher rates sooner. Count a company even if it was only associated for part of the period: HMRC treats it as associated for the whole period. Dormant companies, and some holding companies that only hold shares, do not count.
More info
An accounting period for Corporation Tax can be up to 12 months long. For a shorter period, such as a company's first period or after changing its year end, the £50,000 and £250,000 limits are reduced in proportion to the number of days, measured against the days in each financial year (366 in a year containing 29 February), as HMRC does.
Tailor it to you: dividends from other companies
More info
Dividends your company receives are usually not taxed, but those from companies that are not in the same group are added to your profits when deciding which rate applies. This can push you into marginal relief or the main rate sooner.
- Rates for the financial years from 1 April 2023: 19% small profits rate up to £50,000, 25% main rate from £250,000, and marginal relief in between, with a fraction of 3/200. The Autumn Budget 2026 kept these rates, so the same rates are used for periods ending after 31 March 2027.
- Linked companies share the limits. If your company is associated with other companies (for example, the same person controls them), the £50,000 and £250,000 limits are split between them. Divide each limit by the total number of companies: with one associated company, that is 2 companies, so the limits become £50,000 ÷ 2 = £25,000 and £250,000 ÷ 2 = £125,000.
- Shorter periods get smaller limits. If your accounting period is shorter than 12 months, the limits shrink in line with the number of days. For a 183-day period: £50,000 × 183 ÷ 365 = £25,068.49. A year that includes 29 February has 366 days.
- When to pay. Corporation Tax is due 9 months and 1 day after your accounting period ends: for a year ending 31 March 2027, that is 1 January 2028. The tax return is due later, 12 months after the period ends (31 March 2028 in that example). Companies with profits over £1.5 million pay in four instalments instead.
- Worked to the penny. Each amount is rounded to the nearest penny as it is worked out, and every later figure uses those rounded amounts, so the workings always add up.
Show the workings
Check it with HMRC
These calculations follow HMRC's rules. To read them in full, or to check a figure:
- Rates and limits: Corporation Tax rates and reliefs (GOV.UK)
- How marginal relief works: Marginal Relief for Corporation Tax, and HMRC's own Marginal Relief calculator (GOV.UK)
- Associated companies and shorter periods: HMRC's Company Taxation Manual, CTM03900
- When to pay: Pay your Corporation Tax bill: deadlines (GOV.UK)
For a plain-English walk-through with examples, read Corporation Tax marginal relief explained.
Calculated at sjecapital.co.uk/corporation-tax-calculator. Illustrative, not advice. SJE Capital Limited, company no. 15837169.
Spotted something that looks wrong? Tell us and we will check it straight away.