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

Choose the product surface first#

“An app” can mean a service used through a browser, an iPhone application, an Android application or a product available across all three. A useful estimate begins with the audience and the environment in which they need the product. If a customer uses the service once a quarter from an email link, requiring installation may be unnecessary. If a worker relies on a camera or specialised device every day, the platform decision needs more investigation.

These are architecture choices, not fixed discounts. A shared codebase can still need native code. A specialist native feature does not automatically require rebuilding every part of the product twice. Use our native versus React Native guide to test the hardest requirement before deciding.

The invisible work is still part of the product#

Account recovery, permissions, a content or operations dashboard, storage, notifications and payment status may all sit behind a small interface. Ask who can correct a mistake, remove access or reconcile a disputed transaction. Sketch those staff journeys with the customer journey.

For an illustrative field-service app, the visible feature might be “upload a job photo”. The complete task also includes interrupted upload, file size limits, correct customer access, retry behaviour and a way for staff to resolve failures. An estimate that counts one screen but ignores those states is incomplete.

• Write the user roles and which records each may access.
• List the data source, retention needs and migration work.
• Describe offline behaviour and what happens when connectivity returns.
• Specify the backend, administrative tools and support ownership.
• Separate optional features such as chat or recommendations from the first outcome.

A worked mobile-app budget#

The example below assumes a shared mobile implementation for a narrow workflow, a backend and administration, and testing on both platforms. It does not include specialist hardware, complex offline synchronisation or a major data migration. It is our planning example, not a measured project.

At the illustrative 15% reserve, the planning allowance becomes £56,062.50 before tax and external one-off fees. Twelve months at an assumed £600 monthly running cost add £7,200. The combined envelope is £63,262.50. Change the inputs below to reflect actual scope and quotes.

All worksheet inputs are illustrative assumptions chosen to show the arithmetic. They are not market rates, measured project averages or a quotation. Replace them with your team’s estimate. A team-day is one person’s working day: 40 team-days does not automatically mean eight elapsed weeks.

Test the feature that could change the architecture#

A short feasibility exercise can prevent an expensive commitment. For a scanner, camera workflow, offline field form or specialist SDK, ask for a working proof on the devices the first customers use. Record response time, error handling, permissions and recovery. A simulated happy path is not enough.

Agree what the investigation produces: a runnable example, findings, limitations and an updated estimate. If a suitable native bridge is required, price its implementation and upkeep explicitly. Do not infer a universal “React Native saves 50%” figure from sharing some source code.

Where the product depends on app-store distribution, the Apple review guidelines and Google Play policies are the current sources to consult. The applicable rules depend on the app’s content and behaviour; a builder cannot guarantee a store’s decision.

Include the release, not just the build#

A release needs accounts, app identifiers, signing arrangements, screenshots, descriptions, privacy information and a person responsible for responding to review questions. Confirm which deliverables the supplier prepares and which require your input. Ask for a test distribution before the public launch.

Test the first supported device set, including smaller screens and less capable devices where relevant. Check enlarged text, keyboard access where available, unreliable connections and interrupted sessions. Keep the release checklist and results with the handover documents.

Ask for three separate commercial views#

Ask each supplier to separate one-off delivery, external charges and ongoing operations. Request the currency, tax treatment, payment schedule, support period and exclusions in writing. A contingency is a reserve against named uncertainty; it is not an extra feature budget. Keep acquisition spend separate so you can see whether the product is affordable to build and affordable to operate.

Use the software development brief to give suppliers comparable information. If a proposal has a single “app development” total, ask for enough breakdown to understand its coverage. A supplier can retain a fixed fee while still making inclusions and exclusions explicit.

Reduce the first release deliberately#

Launch to the audience and platforms you can support. A single-platform pilot may be sensible when the test customers all use it; it would be a poor assumption if it excludes the people you need to learn from. A browser-first service may work when installable distribution adds little value.

Avoid paying for speculative scale or feature parity before observing real use. Preserve a complete core journey, support and recovery. The best budget decision is the smallest dependable service that can answer the next business question, with a clear route to maintain it.

Build your own budget#

Adjust the assumptions to see the arithmetic. These starting values reproduce the illustrative model above; they are not a quotation. The reserve applies to delivery effort, before external one-off costs. All amounts exclude tax.

Put this guide to work#

Frequently asked questions#

Sources and methodology#

This guide combines editorial analysis with the linked primary sources. Decision frameworks, worksheets and worked examples are our own; examples are illustrative unless explicitly identified as supplier claims or published research. We have not conducted original interviews, comparative supplier testing or a controlled experiment for this article.

1. React Native: getting started ↗

   Primary reference for the platform or practice discussed. Editorial examples and decision frameworks are our own.

   Accessed 16 October 2026
2. Apple App Review Guidelines ↗

   Primary reference for the platform or practice discussed. Editorial examples and decision frameworks are our own.

   Accessed 16 October 2026
3. Google Play policy centre ↗

   Primary reference for the platform or practice discussed. Editorial examples and decision frameworks are our own.

   Accessed 16 October 2026

Source check: 16 October 2026. Platform documentation can change. Published as part of our editorial collection.

Expanded 16 October 2026 with practical decision material, downloads and topic-specific answers. Supplier and platform claims are identified by their linked sources.