Free tool · UK · 2026/27 rates
Corporation Tax Calculator
Work out your UK company's corporation tax for 2026/27 — including the small profits rate, the main rate, and marginal relief in between. Enter your taxable profit to see the bill instantly.
How UK corporation tax works
Since April 2023 the UK has had a two-rate corporation tax system. Companies with taxable profits up to £50,000 pay the small profits rate of 19%. Companies with profits above £250,000 pay the main rate of 25%. Profits between those two thresholds qualify for marginal relief, which tapers the effective rate smoothly from 19% up to 25%.
In practice, a company in the marginal band is charged at the full 25% rate and then marginal relief reduces the bill, using a 3/200 fraction. The effective rate on profit within that band is 26.5%. These rates are confirmed for 2026/27 and the main rate is capped at 25% for the duration of the current parliament.
The rate bands
Thresholds are shared equally between associated companies and reduced proportionally for accounting periods shorter than 12 months.
Common questions
What is the UK corporation tax rate for 2026/27?
Two rates apply. A small profits rate of 19% on taxable profits up to £50,000, and a main rate of 25% on profits above £250,000. Profits in between get marginal relief, for an effective rate between 19% and 25%.
How does marginal relief work?
Your company is charged at 25% and then marginal relief reduces the bill. It uses a 3/200 fraction, and the effective rate on profit in the £50k–£250k band works out at 26.5%.
What are associated companies?
Companies controlled by the same person or group. The £50,000 and £250,000 thresholds are split equally between them, so running several companies lowers each one’s thresholds and can raise your rate.
When is corporation tax due?
For most companies, 9 months and 1 day after the end of the accounting period. Large companies pay in quarterly instalments.
Stay on top of every company deadline
AdminShield tracks corporation tax, Companies House and VAT deadlines, sends reminders before they fall due, and keeps your filings organised — built for UK limited companies and their accountants.
Start freeThis calculator gives an estimate based on published 2026/27 corporation tax rates and the standard marginal relief formula, assuming augmented profits equal taxable trading profits. It is not tax advice. Reliefs, associated company rules and non-group dividend income can affect your actual liability — confirm with HMRC or a qualified accountant.