A custom web application for a UK small or medium business typically costs between £4,000 and £15,000. That range covers client portals, internal tools, dashboards and booking systems built to a fixed scope. Larger platforms with many user types, heavy integrations or complex workflows cost more, and they are usually quoted after a scoping exercise rather than from a price list.
That is the short answer. The rest of this guide explains what moves a project within that range, so you can judge a quote when you receive one.
What a web app is, and why it costs more than a website
A website explains what you do. A web application does something: people log in, see their own data, submit information, and the system responds. A customer portal, a quoting tool, a staff dashboard and a booking system are all web apps.
The extra cost comes from things a brochure site never needs: user accounts and permissions, a database, business rules, security work and testing. A five-page marketing site can be fixed at £999. An app cannot be priced the same way, because every one has different rules behind it.
The five things that decide the price
- Number of user types. A portal with one kind of user (customers) is far simpler than one with customers, staff and administrators who each see different things.
- Number of distinct screens and workflows. Ten screens that do ten simple things cost less than three screens with complicated logic underneath.
- Integrations. Connecting to Xero, Stripe, a CRM, an email system or a supplier’s API adds design, build and testing time for each connection.
- Data migration. Moving years of records out of spreadsheets or an old system into the new one is often underestimated. Clean data is quick; messy data is not.
- Security and compliance. If the app holds personal data, UK GDPR applies and the build needs access controls, audit trails and sensible retention rules. If it touches regulated sectors, there is more again.
Rough guide to what each level buys
- Lower end (around £4,000 to £6,000): one main user type, a small number of screens, simple data, at most one or two integrations. Think a customer document portal or a simple internal tracker.
- Middle (around £6,000 to £10,000): two user types with permissions, several workflows, payments or email automation, and a proper admin area.
- Upper end (around £10,000 to £15,000): multiple user roles, a number of integrations, reporting, and more involved business rules.
- Above that: platforms, marketplaces and anything needing extensive custom logic. These are quoted individually.
These are guide bands, not a price list. Your actual quote depends on the five factors above.
Fixed price versus hourly rates
Many agencies bill by the hour, which sounds fair but moves all the risk to you: the project can only cost more than you expected, never less. A fixed price tied to a written scope reverses that. The agency carries the risk of estimating badly, and you know the number before work starts.
The catch is that a fixed price only works if the scope is clear. A good studio will spend time up front writing down exactly what is included, and will tell you what a change to the scope would cost before doing it.
Costs people forget
The build is not the whole bill. Plan for:
- Hosting and monitoring. The app has to live somewhere, be backed up and be watched.
- Ongoing maintenance. Software dependencies need updating and security patches need applying. An unmaintained app becomes a security risk.
- Changes after launch. Once real users arrive, you will want improvements.
For this reason we publish our support pricing in full: Webapp Care at £199 a month, Webapp Care+ at £499 a month for apps still being developed, and a Priority SLA at £999 a month for apps the business runs on. All are rolling monthly with no minimum term. See website and web app support for what each includes.
How to keep a web app project on budget
- Start smaller than you think. Launch the one workflow that matters most, then add to it. Most apps are over-scoped on day one.
- Write down what “done” means for each feature before work begins.
- Make decisions quickly. Delays in feedback cost more than almost anything else.
- Insist on owning the source code. You should be able to take the project elsewhere.
- Ask what happens when it breaks. Support should be priced before you sign, not after.
What to ask for in a quote
A useful quote lists the screens, the user types, the integrations, what is excluded, the timeline, who owns the code and what support costs afterwards. If any of these are missing, ask.
Next step
If you have a web app in mind, start with a project enquiry. You do not need a finished specification. We will help you scope it, tell you which band it falls into and agree a fixed fee before any build work begins. You can read more about how we work on our web application development page.