SBL Toolbox · Free calculator
App development cost calculator: what will your app cost?
Choose what you are building and what it needs to do. See a rough cost and timeline for a tested prototype and for a full build, with every assumption shown.
Tested prototype
£6,050–£9,900
11–18 days of work · about 2–4 weeks
Full build
£28,600–£45,650
52–83 days of work · about 2–4 months for one developer
See how this is worked out
A full build adds 20% for testing and 15% for project management. The ranges run from 15% under to 35% over the middle estimate, because early estimates tend to run over.
Not sure it's worth a full build yet? Start with a working prototype, test it with the people who'll use it, then decide. That's how we work. See our builds or discuss your idea.
A rough guide for planning, not a quote. It runs in your browser and nothing you choose is sent to us.
01 · How to use it
Get a planning figure in two minutes
- Choose what you are building. A web app, a mobile app, an internal staff tool or a marketplace, and roughly how many screens it has.
- Tick the features it needs. Each feature adds a set number of days. Open “See how this is worked out” to see them.
- Set the level of polish. Choose standard or custom design, and whether you handle sensitive data or need formal audits.
- Use your own day rate. If you have had a quote, enter that rate. Then copy the estimate to share with your team.
02 · Prototype or full build?
Why the estimate shows two figures
A tested prototype is a working version of the core idea, built quickly and put in front of the people who will use it. It answers the question “will this work?” before you spend the full budget.
A full build adds everything a product needs to run day to day: edge cases, testing, security, project management and a finished design. It usually costs several times more than a prototype.
Starting with a prototype means you pay for the full build only once you know the idea works. That is how we work on our builds.
03 · Questions
Frequently asked questions
How accurate is this app cost estimate?
This app cost estimator is a rough guide for planning and budgeting, not a quote. Real costs depend on the detail of each feature, the systems it connects to and who builds it. The range runs from 15% under to 35% over the middle estimate, because early software estimates tend to run over.
What day rate should I use?
UK rates vary widely. Some freelance developers charge around £350 a day, while agencies can charge £1,000 a day or more. The default of £550 sits in the middle. If you have a quote, use that rate.
Why does a mobile app cost more?
Apps for iOS and Android need extra work for each platform, app store submission and testing on a range of devices. The estimator adds time for this when you choose a mobile app.
What is an MVP?
An MVP, or minimum viable product, is the smallest version of a product that is useful to real users. It lets you learn what people need before you build everything. A tested prototype is often the step before an MVP.
Can I get a proper quote?
Yes. Write a brief with our free generator, then send it to us. We will tell you honestly whether a prototype is the right next step.
04 · More free tools
Other tools you might need
Project Brief Generator
Answer guided questions and download a clear brief to share with your team or a developer.
Automation Savings Calculator
See what a repetitive manual task costs each year, and how much automating it could save.
Test the idea before the full build.
We build working prototypes of apps and tools and test them with the people who will use them, so you know what is worth building before you commit the budget.