Software development
How much does custom software cost in the UK? A plain-English guide
What drives the price of a custom web app or software project, rough UK ballparks, and how to keep costs under control — written for non-technical founders.
Chris Mackie8 min read
“How much will it cost?” is the first question almost everyone asks, and the least satisfying answer is “it depends”. So let me explain what it depends on, give you some rough ballparks, and show you how to keep the number sensible.
The honest ballpark
These are rough figures for the UK market, not a quote. Every project differs, and agencies, freelancers and in-house teams all price differently.
| What you’re building | Typical shape | Rough range |
|---|---|---|
| A focused internal tool or simple portal | A handful of screens, one type of user | Roughly £5k–£15k |
| A first version (MVP) of a startup product | Core features only, polished enough for real users | Roughly £15k–£60k |
| A fuller business platform | Multiple user types, integrations, reporting, payments | Roughly £50k–£150k |
| A complex or regulated platform | Heavy integrations, compliance, high scale | Six figures and up |
If a quote is wildly outside the range for what you’re describing, in either direction, ask questions. Very cheap quotes often leave things out; very expensive ones sometimes include far more than you need.
What actually drives the price
Surprisingly, the technology matters least. What moves the number is:
- Scope. How many features, screens and rules? Every extra feature adds design, build, testing and maintenance.
- Complexity of the business logic. “Calculate a price” is simple. “Calculate a price based on 14 rules that vary by customer, region and date” is not.
- Integrations. Connecting to payments, accounting, CRMs or other systems takes time, especially if the other system is poorly documented.
- Who’s using it. An app for 10 staff is easier than one for 100,000 customers.
- Quality bar. Security, testing, accessibility and reliability take effort, and are the things you’ll regret skipping.
- Clarity. Vague requirements cost more, because the unknowns turn into rework.
The biggest cost-saver: build less, first
The cheapest feature is the one you don’t build. A common mistake is trying to build the “complete” product before anyone has used it. Instead:
- Decide what the one thing is that the first version must do well.
- Build that, put it in front of real users and learn.
- Add features in order of value, not in order of excitement.
This approach usually gets you to market faster, spends less money before you have evidence, and avoids building things nobody wants.
Fixed price or day rate?
- Fixed price gives you cost certainty, but only works when the scope is well defined. Expect change requests if you learn something mid-project (and you will).
- Day rate / time-and-materials is more flexible and often more honest about uncertainty, but needs trust and good visibility on progress.
- A hybrid: fixed price for a clearly scoped first phase, then flexible blocks of time, is often the best of both.
Don’t forget the running costs
The build isn’t the end. Budget for:
- Hosting and services: often modest for early-stage products, but worth tracking.
- Maintenance: security updates, bug fixes and small improvements. A common rule of thumb is to expect to spend a meaningful percentage of the build cost each year keeping software healthy.
- Ongoing development: if the product succeeds, you’ll want to keep improving it.
Questions to ask before you sign anything
- What exactly is included, and what’s explicitly not?
- How will we handle changes if something turns out to be different from what we expected?
- Who owns the code, the designs and the hosting accounts?
- Will there be automated tests and documentation?
- What happens after launch, and what does support cost?
Want a realistic number for your idea?
I build custom web applications, MVPs and internal tools as a senior developer, and I’m happy to give you a straight, jargon-free view of what yours might involve. If you already have a quote and want a second opinion, a technical audit is a quick, low-cost way to check it’s sensible. Or just get in touch and tell me what you’re planning.