R&D tax
What records should you keep for an R&D tax relief claim?
Build an R&D tax evidence file as your project runs. Learn what HMRC looks for, how to record technical uncertainty and how to connect qualifying work to costs.
Start with the technical case, not the spending
If you want to claim R&D tax relief, keep records that explain the scientific or technological advance sought, the uncertainty involved, the work undertaken and the associated expenditure. An invoice proves that you bought something. It does not prove that the purchase supported qualifying R&D. Build your evidence around the technical project first, then connect the financial records to it. This gives your technical lead and accountant a shared basis for deciding what belongs in the claim.
HMRC looks for an advance in overall scientific or technological knowledge or capability, not simply something new to your business. The project must involve uncertainty that a competent professional could not readily resolve using available knowledge. Commercial uncertainty, such as whether customers will buy a product, is different. Before collecting costs, use our guide to qualifying R&D and making a claim to separate potentially qualifying activity from routine development, implementation and commercial work.
Create a short project record that engineers can maintain
Give each potentially qualifying project a consistent identifier and create a short technical record. Capture the starting capability, the advance you sought, the limitations of existing approaches and the uncertainty your team needed to resolve. Name the technical lead and record their relevant experience. Keep descriptions specific enough for someone outside the delivery team to understand the problem. Phrases such as 'we developed an innovative platform' describe ambition, but do not explain why the underlying work might qualify.
For example, a manufacturing team might investigate whether a material can retain a required property under a particular combination of operating conditions. Its record should explain what existing knowledge established, what remained uncertain and why standard methods did not provide a readily deducible answer. This is an illustrative example, not an automatic qualification test. Have the relevant competent professional review the explanation and identify supporting sources, including technical literature, supplier specifications, calculations or results from earlier work.
Record experiments and decisions while the work happens
Keep a running log of attempts to resolve each uncertainty. For each investigation, record the question being tested, the method, the result and the next decision. Link to existing evidence rather than rewriting everything: laboratory notebooks, design revisions, test reports, issue tickets and meeting notes may all help. Preserve enough context to explain why a result mattered. A folder of raw measurements is less useful if nobody can identify the hypothesis, configuration or acceptance criteria behind them.
Record unsuccessful approaches as carefully as successful ones. Failure can help explain the uncertainty and the investigation, but failure alone does not establish qualifying R&D. Equally, a successful outcome does not prevent work from qualifying. Note when an uncertainty was resolved or when attempts to resolve it stopped. That boundary matters because later routine testing, production or customer adaptation may fall outside the qualifying activity, even when it remains part of the same wider commercial project.
Connect staff time and expenditure to qualifying activities
Ask finance and the technical lead to agree how costs will be traced to the activities identified. Keep payroll records, relevant invoices, contracts and the calculations used to allocate expenditure. For staff working across several tasks, record a reasonable basis for separating qualifying and non-qualifying activity. Project codes, task records and time records can support that assessment. Avoid applying a single percentage to the whole team without explaining the work each person performed and the evidence supporting their allocation.
Do not assume that every project cost is eligible, or that expenditure qualifies merely because it appears on an R&D budget. Treatment depends on the applicable relief rules and the circumstances of the expenditure. Contracts and statements of work are particularly important where other organisations undertake development. Keep them alongside invoices so responsibility for the work can be examined. Our R&D tax credits hub provides a starting point for reviewing the tax position separately from the technical qualification.
Review the evidence before anyone drafts the claim
At project reviews, ask the technical lead and finance contact to reconcile the evidence. Can they trace each claimed activity from the uncertainty through the investigation to the cost allocation? Do the technical account, project records and financial calculations describe the same work? Resolve inconsistencies before drafting the claim. Keep a clear distinction between evidence created during delivery and explanations reconstructed later. Retrospective explanations should identify their sources and limitations rather than imply that missing records existed at the time.
Common mistakes include copying sales language into the technical narrative, treating all development as R&D and relying on job titles instead of evidence of actual work. Another is asking finance to infer technical uncertainty from invoice descriptions. Give technical judgement to the relevant competent professional and cost reconciliation to someone who understands the accounts. If you need help coordinating technical and funding evidence, our grant consultancy and grant writing services can support the grant side, while tax eligibility remains a separate assessment.
Where to go next
Start with one project rather than trying to rebuild your entire development history at once. Assemble its technical summary, evidence links, activity boundaries and cost schedule. Ask someone who was not involved in delivery to read the file and identify unanswered questions. Then have your technical lead and tax adviser check the substance. Good records do not guarantee relief, but they make it easier to identify unsupported assumptions, exclude non-qualifying work and explain the basis of a claim.
If you are also planning further innovation work, book a 15-minute grant scope and eligibility assessment with GrantUp. Bring your project summary, the unresolved technical challenges and an outline of the work you want to fund. The assessment can help establish whether a grant route merits further investigation. Keep that prospective funding discussion separate from assessing tax relief on expenditure already incurred, and flag any existing public support so its implications can be checked under the applicable rules.
Ready to turn this into a funded proposal?
Book a free 30-minute consultation with a senior grant consultant. We will check your eligibility, match you to the right program, and map out your submission timeline.
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