The short answer
In the UK, a simple internal tool or dashboard for a small business typically costs somewhere in the low thousands of pounds, a customer-facing portal or booking system with logins and payments typically runs into the mid to high thousands, and anything with real complexity, such as a mobile app with offline features or integrations across several systems, can run well into five figures. These are general market ranges, not quotes, and they vary a lot depending on the agency or developer, where they're based, and exactly what you ask for. The only reliable way to know your own figure is a proper scoping conversation. As a guide, our own prices for this kind of work start from £750 for shaping an idea into a clickable prototype; see pricing for the full range.
What actually drives the cost
Price isn't really about "an app", it's about the sum of several separate decisions. These are the ones that move the number most.
1. How many separate things it needs to do
A booking calendar, a payments page and a customer message centre are each a chunk of work. The more distinct features, the more there is to build, test and maintain. A tool that does one thing well is almost always cheaper than one trying to do five things adequately.
2. Who's using it, and how
An internal tool used by three staff who already trust each other needs far less thought around permissions, onboarding and support than a customer-facing portal used by the public. Public-facing software also needs to look and feel professional, which adds design time that an internal dashboard can often skip.
3. Logins, accounts and permissions
The moment people need to log in, you've added password resets, account security, and usually different levels of access (an admin sees more than a customer). This is sensible and often necessary, but it's real work, not a checkbox.
4. Payments
Taking payments means integrating a payment provider, handling failed payments, refunds and receipts, and making sure everything is secure. It's a well-trodden path, but it's not free.
5. Integrations with other systems
If the app needs to talk to your accounting software, your CRM or a booking calendar, that's additional work for every system it touches, and the reliability of that connection matters more as volume grows. Our comparison of Zapier vs Make vs a custom integration is worth reading if you're not sure how deep this needs to go.
6. Design quality
A rough, functional interface for internal use is cheaper than a polished, branded experience for customers. Both are valid choices, but they cost differently.
7. Platform: web, mobile, or both
A tool that works in a browser on a phone or desktop is usually cheaper to build and maintain than a dedicated iOS and Android app, because you're building and testing one thing instead of two or three. A dedicated mobile app is the right call when you need offline access, camera or GPS features, or a presence in the app stores, but it's worth being honest about whether you actually need that or whether a browser-based tool would do the same job for less.
8. Ongoing support and changes
The cost of a project doesn't end at launch. Bug fixes, small improvements and keeping things running as other software updates around it are an ongoing cost, whether that's a retainer with whoever built it or an in-house resource.
General UK market ranges
These are broad, qualitative bands based on typical UK small business projects, not a quote from us or anyone else. Treat them as a rough sense of scale, and always get a proper quote before budgeting a project.
| Type of project | General shape of cost |
|---|---|
| Idea shaping and a clickable prototype | Low, a small fraction of the eventual build |
| A simple internal tool or dashboard | Low to mid thousands |
| A booking system with real scheduling logic | Mid thousands upward |
| A customer-facing portal with logins and payments | Mid to high thousands upward |
| A dedicated mobile app | Often the highest band, due to design, platforms and app store requirements |
| Ongoing support and changes after launch | A smaller recurring cost, separate from the build |
Our own guide prices
Rather than estimate a stranger's project from a table, here's what we actually charge, as guide prices that a fixed quote is based on after a free call:
- Idea shaping and a clickable prototype: guide prices start from £750
- An internal tool or dashboard: guide prices start from £3,000
- A custom booking system: guide prices start from £4,000
- A customer portal: guide prices start from £6,000
- A mobile app: scoped individually after a conversation, since the range is too wide to generalise
See the full pricing page for current ranges and what's included at each level. If you're still deciding whether you need something custom at all, our guide on off-the-shelf or custom software is worth reading first.
How to keep the cost down without cutting corners
- Start with a prototype, not the full build. A clickable mock-up tests the idea with real users before you spend on development, and it's far cheaper to change a prototype than finished software.
- Launch with the smallest version that's genuinely useful. Extra features can follow once the core tool is proven, rather than before it's launched.
- Be honest about mobile vs browser-based. A lot of projects assume they need a mobile app when a browser-based tool, which works fine on a phone, would do the same job for considerably less.
- Budget for support from day one, rather than treating it as a surprise six months after launch.
If you'd rather not do this yourself
We'll give you an honest view of what your idea actually needs, and a fixed-price quote after a free 30-minute call, with no obligation either way. Have a look at our custom apps and tools service, or start your project to get the conversation going.
Frequently asked questions
Why can't I get a fixed price without a conversation?
Because the same word, "app", covers projects that differ in cost by a factor of ten depending on logins, payments, integrations and design. A short discovery call is how every serious developer or agency works out what you actually need before quoting, and it's free with us.
Is a mobile app always more expensive than a web app?
Usually, yes, because it typically means building for more than one platform, meeting app store requirements, and designing for a smaller screen with touch in mind. A web app that works well on mobile browsers is often a cheaper way to reach the same users, unless you specifically need offline access, camera or GPS features, or an app store presence.
What's the cheapest way to test an idea before committing?
A clickable prototype. It looks and feels like the real thing without the cost of building the back-end logic behind it, and it's the step that tends to catch expensive misunderstandings early.
Do ongoing costs continue after the app is built?
Usually, yes, in the form of hosting, occasional updates and support for bugs or small changes. This is typically a smaller, predictable cost compared with the build itself, but it's worth asking about upfront rather than assuming the project ends at launch.
How long does a typical custom app take to build?
A simple internal tool is often measured in weeks. A customer portal or booking system with logins and payments usually takes longer, given the extra testing that logins and payments need. Timelines are agreed as part of the fixed quote.
Will I own the finished app?
With us, yes: you own the code, the accounts it runs on, and your data. It's worth asking any developer this directly before starting, since not every agency works this way.