If your agency builds custom software, you have probably wondered whether the time and cost qualifies for R&D tax credits. The short answer is: it depends on what you are building and why.

HMRC's R&D rules are specific about what counts as qualifying development. Building a standard CRM for a client using off-the-shelf components does not qualify. Building a novel image recognition system that solves a technical problem no one has solved before, that might. The difference comes down to the nature of the work, not the industry you are in.

As ICAEW qualified accountants working exclusively with agency founders, we see this question a lot. Agencies in Manchester's Northern Quarter, Bristol Harbourside, and London's Soho are all building software. Some of it qualifies. Most of it does not. Here is how to tell the difference.

What HMRC Actually Looks For

HMRC uses a five-part test for R&D tax relief. To qualify, your project must:

  • Seek an advance in science or technology
  • Overcome a scientific or technological uncertainty
  • Be related to your company's trade
  • Be a defined project
  • Not be excluded work (like routine software development)

The key phrase is "scientific or technological uncertainty." That means you did not know at the start whether the solution was achievable. You had to experiment, test, and iterate to find out. If you knew from day one how to build it because someone else had already done it, that is not R&D.

For agencies, the most common sticking point is the distinction between routine software development and genuine technological advance. Building a website in WordPress, even a complex one, is not R&D. Building a custom machine learning model to automate a process that currently requires human judgement, that might be.

Custom Software R&D Qualifying Agency: Where the Line Sits

Let us be direct. Most agency software projects do not qualify for R&D tax credits. That is not a judgement on the quality of your work. It is just how the rules are written.

Here is a practical example. A 12-person digital agency billing £800k per year builds a custom project management tool for their own use. It integrates with Xero, tracks utilisation rates, and automates invoice generation. That is clever, useful work. But it is not R&D. Why? Because the technical challenges were all known. Integration with Xero has been done thousands of times. Automating invoice generation is standard. There was no technological uncertainty.

Now take a different scenario. That same agency builds a tool that uses computer vision to automatically tag and categorise thousands of images for a retail client. The images are inconsistent in lighting, angle, and quality. No existing library handles the specific combination of variables. The team has to develop a novel approach to feature extraction. They test multiple architectures, fail repeatedly, and eventually land on a solution that works. That is R&D.

The difference is not the industry. It is the technical challenge.

Off-the-Shelf Software: Almost Never Qualifies

If you are implementing or customising off-the-shelf software, you can stop reading now. It almost certainly does not qualify.

HMRC is clear: configuring existing software, even extensively, is not R&D. Adding plugins, writing integration scripts, or setting up workflows in tools like Salesforce, HubSpot, or Monday.com does not count. The technological uncertainty was resolved by the original developer.

This catches a lot of agencies out. We see founders who have spent weeks building complex automations in Zapier or Make (formerly Integromat) and assume that qualifies. It does not. You are using existing tools in known ways. Even if the combination is novel to your business, it is not novel to the field of technology.

Where Agencies Genuinely Qualify

There are three common scenarios where agency software work qualifies for R&D tax credits.

1. Building Novel Algorithms or Models

If your agency builds custom machine learning models, natural language processing systems, or computer vision tools that solve genuinely new problems, that is R&D. The key is that the technical solution did not exist before you built it.

For example, a PR agency that builds a sentiment analysis tool specifically tuned for the language used in UK financial services press releases. Standard sentiment tools are trained on general text. They misclassify industry-specific terms. The agency has to develop a custom training dataset, test different architectures, and solve the misclassification problem. That is qualifying work.

2. Solving Technical Integration Problems No One Has Solved

Sometimes the R&D is not in the software itself but in how you get different systems to work together. If you are integrating systems in a way that requires genuinely novel technical work, that can qualify.

A recruitment agency building a custom integration between their ATS and a niche job board that uses a proprietary, undocumented API format. The API documentation is incomplete. The team has to reverse-engineer the protocol, build a custom parser, and handle edge cases the API was never designed for. That involves technological uncertainty.

3. Developing New Technical Processes for Client Work

If your agency creates a novel software tool or process specifically to solve a client's technical problem, and that problem had no known solution, the development work qualifies. The client work itself does not. But the R&D phase does.

A web design agency building a custom accessibility testing tool because no existing tool accurately tests for the specific compliance standard their client needs. The team has to develop new testing methodologies, build custom scripts, and validate results manually. That development phase is R&D.

What Does Not Qualify: The Grey Areas

Some agency work sits in a grey zone. Here is how HMRC typically treats it.

Building a custom CMS for a client. Does not qualify. Content management systems are well-understood technology. Even if yours has unique features, the underlying technical challenges are known.

Developing a mobile app for a client's ecommerce store. Generally does not qualify. Mobile app development is routine. Unless you are solving a genuinely novel technical problem, like a new way to handle offline payments in low-connectivity environments, it is standard work.

Creating a data visualisation dashboard. Does not qualify. Data visualisation is a mature field. Building a dashboard that looks different is not R&D. Building a dashboard that uses a new rendering technique to handle datasets larger than anything previously possible, that might be.

Writing custom code to automate a manual process. Does not qualify on its own. Automation is routine. The question is whether the automation required solving a genuine technological uncertainty. If you knew how to automate it before you started, it is not R&D.

How to Structure Your Claim

If you believe your agency's custom software work qualifies, you need to document it properly. HMRC has become significantly more aggressive on R&D claims in the last three years. Poorly documented claims get rejected, and repeat rejections can trigger full HMRC enquiries.

Here is what you need for a defensible claim:

  • A clear project description. What were you trying to achieve? What was the technological uncertainty?
  • Evidence of uncertainty. Emails, meeting notes, technical documents showing that you did not know the solution at the start.
  • Evidence of experimentation. What approaches did you try? Which failed? What did you learn?
  • Time records. Who worked on the R&D project, and for how many hours? This needs to be separate from your routine client work.
  • Cost records. Salaries, subcontractor costs, software licences, materials directly attributable to the R&D project.

If you are using FreeAgent, Xero, or QuickBooks to track your agency finances, set up a separate project or cost centre for R&D work. That makes the claim much easier to substantiate.

The Numbers: What You Could Claim

For an SME agency, the R&D tax credit works through an enhanced deduction on your corporation tax return. For qualifying expenditure, you can deduct 186% of the cost (for expenditure from 1 April 2023 onwards).

Here is a worked example. A 6-person creative agency spends £63,400 on qualifying R&D work over the year. That includes £48,000 in salary costs for two developers working 60% of their time on the project, plus £15,400 in subcontractor costs and software licences.

The enhanced deduction is £63,400 x 186% = £117,924. That reduces the agency's taxable profit. If the agency is paying 19% corporation tax (small profits rate), the tax saving is £117,924 x 19% = £22,405.

If the agency is loss-making, you can surrender the loss for a cash credit of up to 14.5% of the qualifying expenditure. That is a direct cash payment from HMRC.

Common Mistakes Agencies Make

We see the same errors repeatedly. Avoid these.

Claiming for all software development. Only the R&D portion qualifies. If your developers split their time between R&D work and routine client work, only the R&D hours count.

Claiming for work that has already been done. R&D claims must be for work in the current accounting period. You cannot claim for past projects unless you are amending a previous return within the time limit.

Not documenting uncertainty. HMRC wants to see that you genuinely did not know the solution. If your documentation reads like a standard project plan, it will not pass scrutiny.

Using the CEST tool to justify an R&D claim. The Check Employment Status for Tax tool is for IR35, not R&D. Do not confuse the two.

When to Speak to Your Accountant

If your agency has built custom software in the last 12 months and you think it might qualify, speak to your accountant before you file your CT600 corporation tax return. R&D claims need to be submitted with the return or amended within 12 months of the filing date.

If your contractor mix has changed or you have taken on new technical staff specifically for a software project, that is another trigger. Ask your accountant whether the work qualifies before you spend time documenting it.

At Agency Founder Finance, we help agency founders navigate these questions every day. We are ICAEW qualified accountants who understand how agencies work. If you want to discuss whether your custom software project qualifies for R&D tax credits, get in touch.