Corporation Tax Calculator — 2026/27
What is the Corporation Tax Calculator?
UK Corporation Tax is the tax limited companies pay on taxable profits. From 1 April 2023, the small profits rate is 19% (profits up to £50,000) and the main rate is 25% (profits above £250,000). Profits between £50,000 and £250,000 receive marginal relief, giving an effective rate that tapers from 19% to 25%.
Last reviewed: against HMRC rates for 2024/25 & 2025/26.
Corporation Tax — financial year 2026
Worked example
Company profit £150,000: main rate 25% × £150k = £37,500, less marginal relief of (£250,000 − £150,000) × 3/200 = £1,500 → £36,000 CT due.
Frequently asked questions
+What is the corporation tax rate for small companies?
19% on profits up to £50,000. Companies with profits between £50,000 and £250,000 pay the 25% main rate but receive marginal relief — equivalent to an effective rate that tapers from 19% to 25%.
+How does marginal relief work?
Marginal relief = (£250,000 − augmented profits) × 3/200, deducted from the main-rate calculation. It produces a smooth taper between the small-profits rate and the main rate.
+Are the £50k and £250k thresholds reduced for groups?
Yes — both thresholds are divided equally between associated companies. Two associated companies have £25,000 small-profits and £125,000 main-rate thresholds each.
+When do I pay corporation tax?
Nine months and one day after the end of the company's accounting period. Large companies (profits over £1.5m) pay in quarterly instalments.