Research and Development (R&D) tax relief helps UK companies investing in qualifying scientific or technological innovation. However, claiming relief requires more than demonstrating that a business has developed a new product, improved a process or invested money in innovation.
Companies must identify qualifying R&D activities, calculate eligible expenditure, meet HMRC deadlines and provide clear technical explanations supported by appropriate evidence.
This guide explains six important areas of UK R&D tax relief:
- How to estimate potential relief using R&D tax calculator principles.
- How to calculate your R&D claim notification deadline.
- How to assess R&D tax credit eligibility.
- Which R&D qualifying expenditure you can include.
- What the Additional Information Form requires.
- Which R&D evidence templates and records businesses should maintain.
The guide focuses primarily on accounting periods beginning on or after 1 April 2024, when the merged R&D expenditure credit scheme and Enhanced R&D Intensive Support (ERIS) became applicable.
Official guidance: HMRC — Merged RDEC and Enhanced R&D Intensive Support.
1. R&D Tax Calculator: How to Estimate Your Potential Tax Relief
An R&D tax calculator can help estimate the potential financial benefit of qualifying research and development expenditure.
The calculation depends on the company's circumstances, the applicable scheme, the amount of qualifying expenditure and other Corporation Tax considerations.
Understanding the merged RDEC scheme
For accounting periods beginning on or after 1 April 2024, the merged Research and Development Expenditure Credit (RDEC) scheme generally provides a 20% taxable expenditure credit on qualifying R&D expenditure.
The credit is subject to Corporation Tax and other statutory rules. Therefore, the gross credit is not necessarily the net financial benefit received by the company.
Illustrative calculation:
| Calculation | Amount |
|---|---|
| Total project expenditure | £150,000 |
| Identified qualifying R&D expenditure | £100,000 |
| Gross RDEC rate | 20% |
| Estimated gross RDEC credit | £20,000 |
The £20,000 represents the gross credit before Corporation Tax and any other adjustments, restrictions or offsets.
The final benefit depends on the company's circumstances.
Enhanced R&D Intensive Support (ERIS)
Certain loss-making R&D-intensive small and medium-sized enterprises may qualify for ERIS.
For the relevant accounting periods, the scheme generally requires qualifying R&D expenditure to represent at least 30% of the company's relevant total expenditure, subject to detailed statutory rules and exceptions.
ERIS provides an additional deduction of 86% of qualifying R&D expenditure, with a payable tax credit calculated at 14.5% of the surrenderable loss, subject to applicable limits.
The headline figures should not be interpreted as a guaranteed percentage return on R&D spending.
How to estimate potential R&D tax relief
When preparing an estimate, a business should consider:
- The relevant accounting period and applicable scheme.
- Total potentially qualifying R&D expenditure.
- The company's profit or loss position.
- The percentage of total expenditure attributable to qualifying R&D, where ERIS may apply.
- Applicable tax rates, restrictions and other adjustments.
- The assumptions supporting the calculation.
An estimate does not confirm eligibility or determine the final amount claimable. These calculations should be reviewed by a qualified tax professional.
Official resource: HMRC — RDEC and ERIS schemes.
Why supporting records matter
A financial calculation is only as reliable as the figures used.
Businesses should maintain records connecting staff activities, materials, external contractors and other costs to the relevant qualifying R&D work.
Paylists R&D project management and evidence software helps businesses organise their R&D project information for subsequent review.
2. R&D Claim Notification Deadline: When Must You Inform HMRC?
Some businesses must notify HMRC of their intention to make an R&D tax relief claim.
The claim notification requirement generally applies to accounting periods beginning on or after 1 April 2023.
Who needs to notify HMRC?
A company may need to submit a claim notification if:
- It is claiming R&D tax relief for the first time.
- Its previous R&D claims do not satisfy HMRC's relevant three-year exception.
- It has previously made a claim but no longer meets the conditions for exemption from notification.
A company that has claimed previously should not automatically assume it is exempt. HMRC has specific rules concerning the timing and validity of earlier claims.
How to calculate the claim notification deadline
The claim notification period generally ends six months after the end of the relevant period of account.
For example:
| Period of account ends | Illustrative notification deadline |
|---|---|
| 31 December 2026 | 30 June 2027 |
| 31 March 2027 | 30 September 2027 |
| 30 June 2027 | 31 December 2027 |
These are illustrative dates based on HMRC's standard six-month rule.
Companies with unusual accounting periods, changes in accounting dates or previous claims should check the applicable requirements carefully.
Missing a required notification can invalidate an R&D tax relief claim.
Official resource: HMRC — Tell HMRC you want to claim R&D tax relief.
Claim notification and the Additional Information Form are different
The claim notification tells HMRC that the company intends to claim.
The Additional Information Form provides detailed information about the claim and its underlying R&D projects.
A company may need both documents, and they have different submission requirements.
3. R&D Tax Credit Eligibility: Does Your Project Qualify?
Not every innovative project qualifies for UK R&D tax relief.
The central requirement is that the project seeks an advance in science or technology by attempting to resolve scientific or technological uncertainty.
A new product, a successful commercial project or an expensive development effort is not automatically eligible.
R&D tax credit eligibility checklist
Consider the following questions before treating a project as qualifying R&D.
| Eligibility question | What to establish |
|---|---|
| Does the project seek an advance in science or technology? | Identify the scientific or technological improvement beyond the existing baseline. |
| Was there a scientific or technological uncertainty? | Explain what was not known or readily achievable. |
| Could a competent professional readily resolve the uncertainty? | Demonstrate why existing knowledge or standard methods were insufficient. |
| Was work undertaken to resolve the uncertainty? | Identify experiments, investigations, designs, tests and technical activities. |
| Can the qualifying activities be distinguished from routine work? | Identify when the relevant R&D started and ended. |
| Is there supporting documentation? | Retain technical evidence, project records and cost information. |
A project may qualify even if its technical objective was unsuccessful.
Conversely, successful commercial development does not automatically make an activity qualifying R&D.
Example: Engineering project
A manufacturer plans to develop a lightweight component capable of operating under unusually demanding conditions.
The company must determine whether the required strength, weight and durability can be achieved using available materials and manufacturing processes.
Engineers investigate alternatives, develop prototypes, perform tests and record failures.
The project may involve qualifying R&D where the technical problem could not readily be resolved by a competent professional using existing knowledge.
However, merely modifying a standard component to meet an ordinary customer specification would not be sufficient.
Example: Construction project
A construction business develops an innovative modular connection intended to meet demanding structural and thermal performance requirements.
If achieving the required performance involves genuine technological uncertainty and systematic attempts to resolve it, some development activities may qualify.
Ordinary construction, routine compliance work and standard adaptation of established building systems do not automatically qualify.
The role of the competent professional
HMRC expects a competent professional with appropriate expertise in the relevant scientific or technological field to identify and explain the technical advance and uncertainties.
The professional's contribution helps establish whether the problem was genuinely uncertain in the wider field, rather than simply unfamiliar to the business.
An AI assessment can assist with organising information, but it does not replace competent professional judgement.
Official resources:
- HMRC — Check if you can claim R&D tax relief
- Government guidelines on the meaning of R&D
- HMRC — Importance of a competent professional
4. R&D Qualifying Expenditure: Which Costs Can You Include?
Once a company identifies qualifying R&D activities, it must determine the eligible expenditure attributable to those activities.
Not all costs associated with an innovative project will qualify.
Main categories of R&D qualifying expenditure
| Cost category | Examples | Important consideration |
|---|---|---|
| Employee costs | Qualifying salaries, employer National Insurance and pension contributions | Allocate costs to qualifying R&D activities |
| Materials and consumables | Materials, energy and other qualifying items used in R&D | Apply the relevant consumption and ownership rules |
| Software | Software used in qualifying R&D activities | Reasonable apportionment may be needed |
| Data licences and cloud services | Eligible data access, computing and storage services | Specific R&D use requirements apply |
| Externally provided workers | Qualifying workers supplied through staffing arrangements | Contract and worker rules apply |
| Contracted-out R&D | Eligible payments for R&D performed by another party | Eligibility depends on contractual circumstances and statutory rules |
| Clinical trial volunteers | Certain qualifying payments to trial participants | Specific conditions apply |
Allocating expenditure to qualifying activities
Suppose an engineer spends 40% of their working time on qualifying R&D activities and the remaining 60% on routine engineering.
The company may be able to include the appropriate proportion of qualifying staffing expenditure, subject to the relevant rules.
However, the allocation should be based on a reasonable and supportable methodology.
Useful records include:
- Project and activity descriptions.
- Employees involved and their roles.
- Time records or substantiated activity estimates.
- Materials used in experiments or prototypes.
- Purchase invoices linked to relevant R&D activities.
- Contractor agreements and descriptions of work performed.
- Documentation explaining cost allocation percentages.
The importance of project-level cost records
Financial transactions alone rarely explain why expenditure relates to qualifying R&D.
An invoice for testing services, for example, should ideally be linked to the relevant project, technical uncertainty and associated work.
Similarly, an employee's salary record does not establish which part of their work involved qualifying scientific or technological activities.
Connecting technical work to financial records helps businesses prepare a more transparent expenditure analysis.
Official resource: HMRC — Check which R&D costs you can claim.
5. Additional Information Form (AIF): What Does HMRC Require?
The R&D Additional Information Form is a mandatory part of the UK R&D tax relief claim process.
Since 8 August 2023, companies making new R&D tax relief claims must provide the required additional information to HMRC.
The AIF must be submitted before the Company Tax Return (CT600), or earlier on the same day.
If the tax return is submitted before the AIF, HMRC will reject the R&D claim.
What information is needed?
The AIF requires information across several areas.
| Information area | Supporting information businesses should prepare |
|---|---|
| Company information | Company details and relevant accounting periods |
| Claim and expenditure information | Qualifying costs classified by the appropriate categories |
| R&D projects | Details of relevant projects and activities |
| Scientific or technological advance | Baseline knowledge and the advance sought |
| Scientific or technological uncertainties | What could not readily be achieved or deduced |
| Work undertaken | How the business attempted to resolve the uncertainties |
| Outcome | Results of the work and technical progress |
| People responsible | Relevant company contacts, agents and professional expertise |
HMRC specifies how many project descriptions must be provided, depending on the number of projects and their expenditure.
Preparing technical descriptions for the AIF
A well-supported project description should explain:
1. What was the baseline knowledge?
Describe the scientific or technological capability available before the work.
2. What advance was the company attempting to achieve?
Explain the intended improvement in scientific or technological knowledge or capability.
3. What uncertainty prevented the advance?
Identify the scientific or technological obstacle that a competent professional could not readily resolve.
4. What activities were undertaken?
Describe investigations, experiments, prototypes, testing and technical decisions.
5. How did the work address the uncertainty?
Explain the results, including unsuccessful attempts and any remaining limitations.
These questions are easier to answer when the company has retained appropriate records throughout the project rather than reconstructing the entire technical history at the end of the accounting period.
Official resource: HMRC — Additional information required before claiming R&D tax relief.
6. R&D Evidence Templates: Example Records Businesses Can Use
Keeping suitable project evidence is an important part of preparing a supportable R&D tax relief claim.
There is no single universal evidence template that guarantees HMRC acceptance.
However, businesses can adapt structured records to document technical work and associated expenditure.
The following six example R&D evidence templates illustrate the information that may be useful to retain. They are reference examples rather than downloadable forms.
Template 1: Scientific or technological uncertainty log
| Field | Information to record |
|---|---|
| Project name | Name or reference of the R&D project |
| Technical field | Relevant area of science or technology |
| Baseline knowledge | Established capability and available methods |
| Advance sought | Intended scientific or technological improvement |
| Technical uncertainty | Specific problem not readily resolved |
| Competent professional | Name, role and relevant expertise |
| Work undertaken | Approaches tested to resolve the uncertainty |
| Outcome | Results, limitations and unresolved questions |
| Supporting references | Publications, technical reports and relevant evidence |
Template 2: R&D project time and activity record
| Field | Information to record |
|---|---|
| Employee or worker | Person undertaking the activity |
| Project | Relevant R&D project |
| Activity | Description of the work performed |
| Date or period | When the activity occurred |
| Time or allocation | Hours, percentage or supported estimate |
| R&D classification | Qualifying, non-qualifying or requiring review |
| Evidence reference | Associated project record or supporting document |
Template 3: Experiment and technical test record
| Field | Information to record |
|---|---|
| Test reference | Unique test identifier |
| Objective | What the test intended to establish |
| Related uncertainty | Technical issue being investigated |
| Method | Test procedure and conditions |
| Results | Measurements, observations and outcomes |
| Interpretation | What was learned from the results |
| Next steps | Further work or change in approach |
| Supporting files | Reports, charts, photographs and measurements |
Template 4: R&D expenditure allocation record
| Field | Information to record |
|---|---|
| Cost reference | Invoice, payroll or transaction reference |
| Cost category | Staff, material, software, contractor or other |
| Total expenditure | Original recorded cost |
| Project allocation | Relevant project or activity |
| Proposed R&D percentage | Estimated qualifying proportion |
| Allocation basis | Methodology and justification |
| Proposed qualifying amount | Amount for professional review |
| Review status | Draft, reviewed or adjusted |
Template 5: Subcontractor R&D record
| Field | Information to record |
|---|---|
| Supplier | External party performing the work |
| Contract reference | Relevant agreement or purchase order |
| R&D description | Technical work being contracted |
| Project and uncertainty | Relevant scientific or technological objective |
| Deliverables | Reports, designs, prototypes or results |
| Expenditure | Amount invoiced or paid |
| Contractual assessment | Information needed to establish the claiming party and qualifying costs |
| Supporting documents | Agreement, invoices and evidence of work |
Template 6: Competent professional review record
| Field | Information to record |
|---|---|
| Reviewer | Competent professional's name |
| Expertise | Relevant qualifications and professional experience |
| Project | Project being reviewed |
| Technical uncertainty | Uncertainty being assessed |
| Baseline assessment | Confirmation of relevant existing knowledge |
| Activities reviewed | Technical work and evidence considered |
| Conclusion | Assessment of scientific or technological eligibility |
| Review date | When the review was completed |
| Outstanding issues | Additional evidence or clarification required |
Why ongoing evidence collection matters
Project activities evolve. Technical uncertainties may be resolved, new problems may emerge and teams may change their approach.
Records created close to the time of the actual work can make it easier to establish what was known, what was uncertain and why particular technical decisions were made.
Historical records can still be useful, but late reconstruction may make it harder to demonstrate the original technical context.
Official reference: HMRC — Expectations of R&D claimants.
7. How Paylists Supports R&D Project Management and Evidence Preparation
The six areas covered in this guide are connected.
Eligibility assessments rely on technical project information. Expenditure calculations require a reliable connection between costs and qualifying activities. The Additional Information Form depends on clear descriptions of the work undertaken.
Paylists brings R&D project management and evidence preparation into one workflow.
Businesses can manage their R&D projects and maintain information about:
- Scientific and technological uncertainties.
- Project activities and work packages.
- Technical investigations, tests and results.
- Supporting technical documents.
- Project costs and expenditure allocations.
- Competent professional assessments.
Using Lister AI to support evidence preparation
Lister AI helps businesses organise scientific and technological uncertainty information, prepare structured technical answers and consider relevant external research publications.
Its purpose is to support the technical evidence preparation process, not to replace professional judgement.
Collaboration with R&D tax advisors
R&D tax advisors can review relevant project and evidence information before preparing the claim.
This helps connect technical project information with the financial and narrative requirements of UK R&D tax relief.
Paylists does not replace an R&D tax advisor, guarantee claim eligibility or submit claims to HMRC.
Learn more:
8. Frequently Asked Questions
Can I use an R&D tax calculator to determine my final claim?
An R&D tax calculator can provide an indicative estimate, but the final amount depends on the applicable scheme, qualifying expenditure, company financial circumstances and statutory restrictions. The calculation should be reviewed by an appropriately qualified professional.
When is the R&D claim notification deadline?
Where a notification is required, the standard deadline is six months after the end of the relevant period of account. HMRC's detailed rules and exceptions should be checked.
Can a project qualify if it fails?
Yes. An unsuccessful technical outcome does not automatically prevent a project from qualifying, provided the relevant scientific or technological criteria are met.
Are all engineering or software development costs eligible?
No. Only eligible expenditure attributable to qualifying R&D activities can be included, subject to the applicable cost rules.
Is the Additional Information Form mandatory?
Yes. The AIF is required for new R&D tax relief claims under the rules introduced from 8 August 2023.
Does HMRC require a particular R&D evidence template?
HMRC does not prescribe one universal template for every project record. Businesses should retain sufficient, relevant evidence to support the technical and financial information included in their claim.
Can AI decide if my R&D project qualifies?
AI can help identify missing information, structure evidence and prepare draft technical explanations. It should not be treated as a substitute for competent professional assessment or tax advice.
Conclusion
Preparing a UK R&D tax relief claim involves more than calculating expenditure.
Businesses should understand the applicable R&D tax scheme, verify project eligibility, meet claim notification deadlines, identify qualifying costs and maintain appropriate evidence.
The strongest approach is to integrate evidence collection into normal R&D project management rather than relying entirely on reconstructing technical records at the end of the year.
Paylists supports this approach by combining project management, technical evidence preparation, AI assistance and advisor collaboration.
Explore Paylists R&D Project Management and Evidence Software
Important information: This article provides general educational information about UK R&D tax relief based on HMRC guidance available as of 22 October 2026. It does not constitute tax or legal advice. Rules and company circumstances vary. Seek professional advice before preparing or submitting a claim.