"How much does it cost to build an app?" is the first question almost every founder asks us, and it's also the hardest to answer honestly without more detail. An app can cost £15,000 or £500,000 depending on what it does, who builds it, and how it's built. Agencies that quote a number before understanding your idea are guessing — or worse, low-balling to win the work and clawing it back later. This guide gives you the honest cost bands we see in the UK market, explains what actually drives the price up or down, and shows you how to budget without nasty surprises. These are broad market ranges, not a quote — your mileage will vary.
UK app development cost bands by app type
Most UK-built apps fall into one of these bands. Prices assume professional UK development (design, build, testing and launch) — offshore or freelancer rates can be lower, with trade-offs we'll cover below.
Simple apps: £15,000–£40,000
A focused utility or content app: standard screens, basic user accounts, simple backend or CMS-driven content, no complex integrations. Think calculators, directories, event apps, simple booking flows. One platform (iOS or Android), modest design, a few weeks to a few months of work.
Mid-complexity apps: £40,000–£100,000
This is where most serious consumer and business apps land. Custom UI, user accounts with profiles, social features, payments, maps, messaging, integrations with third-party APIs, an admin panel, and a proper backend. iOS and Android (or cross-platform), a proper design phase, real QA. Expect 3–6 months.
Complex apps: £100,000–£250,000+
Marketplaces, on-demand platforms, fintech, health apps with compliance needs, apps with real-time features (live tracking, video, chat at scale), AI/ML features, or heavy custom backend architecture. Multiple integrations, serious security requirements, 6–12+ months, and a team rather than a couple of developers.
The honest headline: most viable consumer apps built in the UK land between £50,000 and £150,000 for a proper first version on both platforms. Anyone promising a marketplace app for £8,000 is either cutting corners you'll pay for later or doesn't understand the brief. For a deeper look at how agencies scope this kind of work, see our article on web app project estimation.
What actually drives the cost
1. Platforms: one or two?
Building natively for both iOS and Android roughly doubles the build effort for the app itself (the backend is shared). Cross-platform frameworks like Flutter or React Native let one codebase serve both, typically saving 30–40% versus two native builds. For most startups, cross-platform is the sensible default; go native only when you need deep platform-specific performance (heavy gaming, AR, complex video).
2. Backend and integrations
The app users see is often the smaller half of the job. User accounts, databases, admin panels, payment processing (Stripe, Apple Pay), maps, push notifications, SMS, analytics, third-party APIs — each integration is design, code, testing and maintenance. Apps that "just" connect to five external services are never as simple as they sound.
3. Design quality
Template-feel versus genuinely good UX is a real cost line: user research, wireframes, UI design, prototyping and usability testing. Skimp here and you pay in user acquisition costs later, because a confusing app bleeds the expensive users you paid to acquire. Design typically runs 15–25% of the budget.
4. Compliance and security
Fintech, health and children's apps carry regulatory weight — FCA considerations, medical data rules, age-appropriate design code — that adds security architecture, audits and legal review. If your app handles payments or sensitive personal data, budget for proper security work and penetration testing, not just a checkbox.
5. Testing and launch
Proper QA across real devices, OS versions and edge cases; App Store and Google Play submission (including review rejections and resubmissions — Apple's review alone trips up plenty of first-timers); analytics setup; launch monitoring. This phase is routinely underestimated by first-time founders.
The costs nobody puts in the first quote
- Maintenance: budget 15–20% of the build cost per year. OS updates, library updates, bug fixes, small improvements — an app is a living product, not a one-off purchase.
- Backend hosting and services: servers, databases, push notification services, SMS, maps API usage, payment processing fees. These scale with users.
- App store fees: Apple charges $99/year for a developer account; Google Play is a $25 one-off. Apple's 15–30% cut on in-app purchases also shapes your business model.
- Marketing and user acquisition: building the app is often the cheaper half of launching a successful app. Organic discovery in app stores is brutal.
- Iteration: your v1 will be wrong in places. Budget for learning from real users and fixing what the data tells you.
How quotes are structured: fixed price vs time and materials
UK agencies generally quote either fixed price (a set scope for a set fee — good when requirements are clear and stable) or time and materials (you pay for actual time spent — better when the scope will evolve, which for startups is most of the time). Fixed price feels safer but often hides contingency padding and punishes change requests; T&M is more honest for evolving products but needs trust and transparency. We've written a full breakdown of fixed price vs time and materials if you're weighing the two.
How to keep costs down without building junk
- Cut scope, not quality. Launch with the smallest version that delivers the core value (a real MVP), then let usage data decide what gets built next. Most v1 feature lists can lose half their items without losing the point.
- Go cross-platform unless you have a concrete native-only requirement.
- Use proven services for payments, auth, maps and chat instead of building them. Your differentiation is your product, not your login screen.
- Phase the work. Design and validate first (cheaper to change a Figma file than a codebase), then build.
- Budget for maintenance from day one so you're not scrambling when iOS 27 breaks something.
Be wary of quotes dramatically below market: an app quoted at a third of everyone else's price usually means junior or overstretched developers, no QA, no design process, or a scope so narrow it won't survive contact with real users. The cheapest quote is rarely the cheapest app — rebuilds cost more than doing it properly once.
If you're budgeting an app idea and want an honest sense of where it lands, our custom mobile app development team scopes projects properly before quoting — no finger-in-the-air numbers. Get a free consultation and we'll walk through your idea, tell you what's driving the cost, and what you could sensibly cut for v1.
FAQs
What's the average cost of app development in the UK?
There isn't a meaningful single average, but most professional consumer apps built in the UK cost £50,000–£150,000 for a first version on iOS and Android. Simple apps start around £15,000–£40,000; complex platforms run £100,000–£250,000+.
Is it cheaper to build for iOS or Android first?
Marginally — building one platform first roughly halves the app-side cost. iOS-first is common for UK consumer startups (higher-spending users, simpler device fragmentation); Android-first makes sense if your audience skews Android. Cross-platform frameworks increasingly make this a moot point.
How much does app maintenance cost per year?
Budget 15–20% of the original build cost annually for updates, OS compatibility, bug fixes and small improvements. Complex apps with backends and integrations sit at the higher end.
Why do app quotes vary so much between agencies?
Because "an app" isn't one thing. Quotes differ on scope interpretation, platform strategy, design depth, QA rigour, who's doing the work (senior UK team vs junior offshore), and what's excluded (maintenance, backend hosting, App Store submission). Always compare detailed breakdowns, not headline numbers.
Can I build an app for under £10,000?
You can build something — a no-code prototype, a very simple single-platform utility, or an MVP built by a freelancer. But a professionally designed, tested, two-platform app with a backend won't happen at that price in the UK market. Under £10k, be clear-eyed about what you're actually getting.
