How much does custom software cost in the UK?

What actually drives the cost

Almost all of the cost sits in people's time. So the question is not really 'how much does software cost', it is 'how many weeks of design and engineering does this need, and at what rate'.

• Scope: the number of distinct screens, roles and rules, not the number of features on a list.
• Integrations: anything that talks to a system you do not control adds testing and failure handling.
• Data: migrating messy existing data is often the single most underestimated task.
• Compliance: payments, health data or regulated processes add review and evidence work.
• Design: bespoke interface work costs more than adapting an existing design system.

Rough shapes of work

Rather than quoting figures we cannot stand behind, it helps to think in shapes. A focused internal tool that replaces a spreadsheet is a small, weeks-long piece of work. A customer-facing product with accounts, payments and an admin side is a multi-month engagement. A platform serving many organisations, with billing and permissions, is a programme of work that continues after launch.

When you receive quotes, ask which shape the supplier thinks they are quoting. Large gaps between quotes usually mean the suppliers are imagining different shapes, not that one is cheap.

How to keep the first phase affordable

The cheapest software is the software you did not need to build. Before development starts, agree the one outcome the first release must deliver, and let everything else wait.

• Start with the workflow that costs the business most time today.
• Use established components for anything that is not your differentiator.
• Ship to a small group of real users before widening the scope.
• Agree a written scope with assumptions, so change is a decision rather than an argument.

Questions worth asking any supplier

A good supplier will be comfortable with all of these: what is excluded from this price, what happens if an integration behaves differently than documented, who owns the code, what does support cost after launch, and what would you cut first if the budget had to drop by a third.