R&D Tax Relief in 2026: What UK SMEs Can Still Claim Under the Merged Scheme

If your last R&D claim came in lower than expected, you are not alone. For accounting periods beginning on or after 1 April 2024, HMRC merged the old SME scheme and RDEC into a single regime, and most UK small companies are now claiming under rules that look very different from the ones they remember.

By the 2026 filing season, almost every claim being prepared falls under the merged scheme. The headline rate is 20 percent, given as a taxable above the line credit. After corporation tax, that lands somewhere between 15 and 16.2 percent of qualifying spend for a profitable company. The old "33 percent back" figure no longer applies, and pitching investors or co-founders on the old numbers will quickly become an awkward conversation.

Who still qualifies, and who does not

The merged scheme covers most trading companies that carry out a qualifying project. There is a separate, more generous route for R&D intensive loss makers, called ERIS, which gives a 27 percent effective credit. To use it, your qualifying R&D spend must be at least 30 percent of total tax deductible costs for the period, and the company has to be loss making. That 30 percent threshold is strict. If you scrape in at 29 percent because of a single contractor invoice falling outside the period, you are back in the standard merged scheme.

Subsidised and contracted out work has also been reshaped. Under the merged rules, the company that decides the R&D needs doing, and bears the financial risk, is usually the one entitled to claim. If a customer is paying you to solve their technical problem, read the contract carefully before assuming the relief is yours.

What HMRC actually counts as R&D

The definition has not changed, but enforcement has. HMRC now opens enquiries on a much larger share of claims, and the team reviewing them is more technical than it used to be. To qualify, your project must seek an advance in science or technology, and the advance has to involve resolving scientific or technological uncertainty that a competent professional in the field could not readily work out.

Building a standard ecommerce site is not R&D. Integrating two off the shelf APIs is not R&D. Training a model on your own data, in a way that required you to invent a new approach because the standard methods failed, can be. The honest test is whether a senior engineer or scientist in your field would have to stop and think, then experiment, rather than simply look up the answer.

Qualifying costs in 2026

The categories that survived the reform are:

1. Staff costs, including employer NIC and pension contributions, for the time spent on qualifying work.
2. Externally provided workers, typically agency staff, restricted to 65 percent of the cost.
3. Subcontracted R&D, also restricted to 65 percent, with new rules on who actually owns the claim.
4. Consumables used up in the R&D process, including a fair share of utilities.
5. Software and, since April 2023, data licences and cloud computing costs used in the R&D.

Two changes catch out UK SMEs in particular. First, overseas subcontractor and externally provided worker costs are now mostly outside scope, with narrow exceptions where the work genuinely cannot be done in the UK. Second, costs have to relate to a project named and described in the additional information form, which is now compulsory. No form, no claim.

Where claims get rejected

The pattern from HMRC enquiries over the last two years is fairly consistent.

Vague project descriptions are the single biggest problem. Phrases such as "developing a new platform" or "improving our algorithms" tell HMRC nothing about the uncertainty involved. A short, specific narrative that names the technical baseline, the uncertainty, and the steps your team took to resolve it does far more work than ten pages of marketing copy.

The second pattern is poor time tracking. If your finance team apportions staff time at a round 50 or 75 percent for every developer, expect questions. Even a lightweight timesheet, kept during the period rather than reconstructed afterwards, makes the difference between a smooth claim and a long enquiry.

The third is claims made by advisers on a contingent fee, with no involvement from a competent professional inside the business. Those firms are now a specific focus area for HMRC. If you are using one, make sure the technical narrative comes from your own team, not from a template.

A practical checklist before you file

Before you sign off your 2026 claim, work through five questions.

First, can you name the specific technological uncertainty you faced, in one sentence, without using marketing language. Second, can a competent professional in your field confirm in writing that it was a genuine uncertainty. Third, have you separated qualifying from non qualifying work in your costings, rather than claiming a percentage of total payroll. Fourth, have you checked whether any of the work was subsidised, contracted out, or done overseas. Fifth, is the additional information form complete and consistent with the technical narrative.

If the answer to any of those is no, the claim is not ready, regardless of what the headline number looks like.

The bottom line

R&D relief is still one of the most valuable incentives a UK SME can use, and the merged scheme has not changed that. What has changed is the standard of evidence HMRC expects, and the speed at which weak claims now collapse. Treat it as a finance and engineering project together, not a year end paperwork exercise, and the 15 percent or so of qualifying spend that comes back is real money you can reinvest with confidence.