The rates for today and for the past few years are as follows:
Year beginning 1 April: | 2021 | 2022 | 2023 | 2024 | 2025 |
Corporate Tax main rate | 19% | 19% | 25% | 25% | 25% |
Corporate Tax small profits rate | N/A | N/A | 19% | 19% | 19% |
Marginal relief lower profit limit | N/A | N/A | £50,000 | £50,000 | £50,000 |
Marginal relief upper profit limit | N/A | N/A | £250,000 | £250,000 | £250,000 |
Standard fraction | N/A | N/A | 3/200 | 3/200 | 3/200 |
Main rate (all profits except ring fence profits) | 19% | 19% | N/A | N/A | N/A |
From 1 April 2023, the Corporation Tax main rate applies to profits over £250,000, and the small profits rate applies to profits of up to £50,000. Those thresholds are divided by the number of associated companies carrying on a trade or business for all or part of the accounting period. Companies with profits between £50,000 and £250,000 pay tax at the main rate reduced by a marginal relief determined by the standard fraction and this formula:
Where:
F = standard fraction
U = upper limit
A = amount of the augmented profits
N =amount of the taxable total profits
For companies with ring fence profits from oil or gas related activities, the main rate is 30%, and the small profits rate is 19%, with a ring fence fraction of 11/400. This has applied for all financial years from 2008.
From 1 April 2024, a new merged R&D scheme replaced the previous SME and RDEC schemes for most companies. However, a modified SME scheme — called Enhanced R&D Intensive Support (ERIS) — remains available for R&D-intensive, loss-making SMEs as of April 2025.
Companies cannot claim both ERIS and the merged scheme for the same expenditure but can choose between them if eligible.
Provided a 230% deduction before April 2023; reduced to 186% from April 2023.
Loss-making SMEs could surrender losses for:
For large companies or SMEs not eligible for the SME scheme.
Offered a 20% taxable credit on qualifying R&D spend.
In conclusion, from 1 April 2024, the previous SME and RDEC schemes have been consolidated into a single R&D Tax Relief scheme for most companies, with the exception of the new Enhanced R&D Intensive Support (ERIS) scheme, which remains available for R&D-intensive, loss-making SMEs.
The key difference is that the merged R&D Tax Relief scheme now applies to most companies, whereas the Enhanced R&D Intensive Support (ERIS) scheme is specifically for R&D-intensive, loss-making SMEs, which was not the focus of the previous schemes.