How much does it cost to build a mobile app in the UK?

What you are actually paying for

Almost every disappointing app project starts with a client comparing a £15,000 quote against a £70,000 quote and assuming one supplier is greedy. Usually they are quoting different things.

A mobile app is rarely just an app. A realistic scope includes:

• The mobile client — the thing users download. Often only 35-45% of total effort.
• The backend and API — authentication, business logic, data storage, push notifications, file handling, payments.
• An admin portal — so your team can manage users, content and configuration without a developer and a store release.
• Design — UX flows, UI design, and design for two platforms' conventions.
• QA — functional, integration and device testing. Not the developer checking their own work.
• Release and store submission — App Store and Play compliance, privacy manifests, data-safety declarations, phased rollout.
• Infrastructure — hosting, monitoring, crash reporting, analytics.

If a quote does not itemise these, ask which of them it excludes. The answer is usually revealing.

Cost by app type

These are the ranges we see in the UK market in 2026, for work delivered by a competent agency or consultancy with QA and project management included.

Freelancers and offshore-only suppliers will quote well below these figures. Sometimes that works. The failure mode is not usually bad code — it is no QA, no documentation, no handover, and nobody available in eighteen months when iOS forces an SDK upgrade.

The five factors that move the price most

1. Number of platforms

Two native apps cost roughly 1.7 to 1.9 times one. Cross-platform with React Native or Flutter typically lands at 1.1 to 1.3 times — the saving is real, but it is not half, because platform- specific work, testing and release management do not disappear. Our native versus cross-platform guide works through when the trade is worth it.

2. Integrations

The single biggest source of overrun. Connecting to a modern, well-documented REST API might be two days. Connecting to a fifteen-year-old reservation system with no API, inconsistent data and no test environment can be six weeks. Integration cost is driven by the quality of the other side, not by your app.

3. Offline capability

"It should work without signal" is a small sentence with a large price tag. Local persistence, sync, and above all conflict resolution — deciding what happens when two people edited the same record offline — commonly adds 20-35% to app effort.

4. Design ambition

Standard platform components are cheap and, frankly, often better. Custom animation, bespoke components and a distinctive visual identity add cost in design, build and QA. Worth it for a consumer product; rarely worth it for an internal tool.

5. Compliance and security requirements

Regulated sectors, penetration testing, SSO with an enterprise identity provider, audit logging, data residency and accessibility conformance all add real effort. They are also usually non-negotiable, so establish them in discovery rather than discovering them at UAT.

What quotes leave out

Four costs are routinely absent from proposals, and all four are certain:

1. Store and platform fees. Apple Developer Program £79/year, Google Play a one-off $25. Trivial, but people forget them.
2. Hosting and services. £50 to £600 a month for a typical business app on Azure or AWS, depending on traffic and redundancy. Push notification, SMS, email and mapping services add more.
3. Maintenance. Budget 15-20% of build cost per year. This is not optional: iOS and Android force annual SDK and API-level upgrades, and an app left untouched for two years often will not compile, let alone pass review.
4. Iteration after launch. Your first release will be wrong about something. Real usage data always produces a list. Teams that budget nothing for post-launch change end up with a frozen product.

Where money gets wasted

In our experience the waste is nearly always one of these:

• Building version two first. Features added "while we are in there" that no user has asked for. The most expensive code is code nobody uses.
• Skipping discovery. Two weeks of paid scoping routinely saves two months of build. Requirements discovered mid-sprint cost several times more than requirements discovered on a whiteboard.
• No admin portal. Saving £8,000 by omitting it, then paying a developer day rate every time a price, a piece of content or a user permission needs changing.
• Native when cross-platform would do. Paying twice for two codebases to build an internal forms-and-approvals app.
• Cheapest supplier, then a rescue project. We are frequently the second supplier. Rebuilding is almost always more expensive than building once.

How to reduce cost without wrecking the product

• Cut scope, not quality. Fewer features built properly beats many features built carelessly. Ship a narrow v1 and let usage decide what comes next.
• Go cross-platform unless you have a specific reason not to. For most business applications React Native or Flutter is the right commercial call.
• Launch on one platform first if your audience skews clearly to iOS or Android. Validate, then port.
• Use platform-standard UI. Users already know it, and it costs a fraction of bespoke design.
• Be honest about your budget in the first call. A supplier who knows you have £45,000 can design something excellent for £45,000. A supplier guessing will either over-scope and lose, or under-scope and disappoint.

If you are working through a number for a specific app, we are happy to sanity-check it — see mobile app development or get in touch.