UK Corporation Tax Rates 2026/27: 19% Small Profits to 25% Main Rate
UK Corporation Tax rates for 2026/27, including the 19% Small Profits Rate, 25% Main Rate, Marginal Relief between £50,000 and £250,000, associated-company rules and filing and payment deadlines.
Key Statutory Takeaways
Statutory Rules & Core Thresholds
Small Profits Rate: 19% on taxable profits up to £50,000. Main Rate: 25% on profits over £250,000. Marginal Relief fraction: 3/200 between £50,000 and £250,000.
In-Depth Legal Framework & Analysis
For the financial year 2026/27, UK Corporation Tax operates a tiered rate structure. Companies with taxable profits of £50,000 or less pay the Small Profits Rate of 19%. Companies with taxable profits exceeding £250,000 pay the Main Rate of 25%. Between £50,000 and £250,000, Marginal Relief applies using a statutory fraction of 3/200, effectively smoothing the transition between 19% and 25%. The £50,000 and £250,000 limits are reduced proportionately for accounting periods shorter than 12 months and are divided by the total number of associated companies (1 + N). CT600 tax returns are due within 12 months of the period end, while tax payment is generally due 9 months and 1 day after the period end, except for large companies (£1.5m+) which must pay via quarterly instalment payments (QIPs).
Company Tax Return (CT600) due 12 months after accounting period end. Corporation Tax payment due 9 months and 1 day after accounting period end (or quarterly instalments for large companies over £1.5m).
Late CT600 filing: £200 initial penalty (1 day late), another £200 at 3 months, 10% unpaid tax at 6 months, and another 10% at 12 months. £1,000 each if late 3 consecutive times.
Corporation Tax Rates 2026/27
Corporation Tax Marginal Relief
£50,000 to £250,000 taxable profitsMarginal Relief provides a gradual increase in the effective Corporation Tax rate between the 19% Small Profits Rate and the 25% Main Rate.
Marginal Relief is calculated using the statutory formula and the 3/200 standard fraction, taking account of augmented profits and relevant distributions where required.
Associated Companies
The £50,000 Small Profits Rate limit and £250,000 Marginal Relief upper limit are divided by the number of associated companies.
Corporation Tax Deadlines
Filing Deadline: Usually 12 months after the end of the accounting period.
Deadline: 9 months and 1 day after the end of the accounting period.
Companies with taxable profits of £1.5 million or less, subject to the payment rules.
Corporation Tax is generally paid in quarterly instalments.
Late CT600 Penalties
| Delay Past Deadline | Statutory HMRC Penalty |
|---|---|
| 1 day late | £200 |
| 3 months late | Another £200 |
| 6 months late | 10% of the unpaid Corporation Tax |
| 12 months late | Another 10% of the unpaid Corporation Tax |
Note: Late filing penalties can apply even where the company has no Corporation Tax to pay.
Companies With Special Corporation Tax Rates
Marginal Relief: Available between the relevant £50,000 and £250,000 limits using the ring-fence fraction of 11/400.
Scope: Ring-fence rates apply to qualifying profits from oil extraction or oil rights in the UK and UK Continental Shelf.
Corporation Tax Deadlines
Frequently Asked Questions: UK Corporation Tax Rates 2026/27: 19% Small Profits to 25% Main Rate
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Primary Statutory Authority
Frequently Asked Questions
The Small Profits Rate is 19% for companies with taxable profits of £50,000 or less. The Main Rate is 25% for taxable profits above £250,000. Companies between those limits can receive Marginal Relief.
Marginal Relief applies where taxable profits are more than £50,000 and less than £250,000, subject to the statutory rules. The standard Marginal Relief fraction is 3/200.
Yes. The £50,000 and £250,000 limits are divided by the number of associated companies. For example, with 2 associated companies in total, the limits become £25,000 and £125,000. Short accounting periods can reduce them further.
A CT600 is normally due 12 months after the end of the accounting period it covers. This is separate from the Corporation Tax payment deadline.
For companies with taxable profits of £1.5 million or less, Corporation Tax is normally due 9 months and 1 day after the end of the accounting period. Companies with profits above £1.5 million generally pay by quarterly instalments.
The initial penalty is £200 when the return is 1 day late, followed by another £200 after 3 months. At 6 months, a penalty of 10% of unpaid Corporation Tax can apply, with another 10% at 12 months. Repeated late returns can result in higher fixed penalties.
Common Taxpayer Misconceptions
✓ Rule: The 19% rate applies where taxable profits are £50,000 or less, subject to associated-company and short-period adjustments.
✓ Rule: Associated companies include companies under common control by individuals or connected persons, broader than a simple group structure.
✓ Rule: Initial late filing penalty for a CT600 is £200 at 1 day late, followed by another £200 at 3 months.
✓ Rule: Large companies with taxable profits over £1.5 million must pay Corporation Tax in quarterly instalments.