How Long Does It Take to Build a Mobile App? What Actually Moves the Timeline

The short answer

Every honest answer to this question is a range, and the range is wide because the question is underspecified. A booking app with one integration and a platform with role-based access, payments and an admin back office are both "a mobile app".

So instead of a market average, here is one project we can account for hour by hour. Our largest recent platform came in at 3,086 hours over 31 weeks with a team of five to six people. Design, development, QA, release. That is the anchor everything below is measured against, and it is the only project number on this page.

Why 3,086 hours is not 77 weeks, and not 10

The first mistake in planning is dividing hours by 40. If one person works 40 hours a week, 3,086 hours looks like 77 weeks for one developer, or about 15 weeks for a team of five. Neither number ever happens.

The reason is that a working week is not a productive week. Standups, code review, design handover, clarifications, a broken pipeline, an interview, a sick day. When we plan, we count about 18 focused hours per person per week. Not because people are lazy, but because that is what is left after everything a real team does around the work.

Check it against the project above:

31 weeks x 5.5 people x 18 hours = 3,069 hours. Delivered: 3,086. The planning number and the real number are 0.55 percent apart.

That is the whole trick. If a vendor gives you a timeline that only works at 40 hours a week per person, they have not planned the project, they have divided a number.

Where the hours actually go

Development is not the whole build. Across our work the split is roughly 70 percent design and development, 15 percent QA, 15 percent project management. Applied to the same project:

• Design and development: about 2,160 hours
• QA: about 463 hours
• Project management: about 463 hours

This matters when you compare quotes. An estimate that shows only development hours is not cheaper, it is incomplete. The QA and the coordination still happen. They are either in the plan or they are a surprise in month four.

Adding people does not shorten the calendar

The most common request we get after a first estimate is to compress the timeline by adding developers. It works, but not the way it looks on paper, and never proportionally.

The work does not shrink when you add people. It runs in parallel, which means more interfaces between parts, more coordination, more review, and more rework when two people solve the same problem differently. Doubling the team does not halve the calendar. It buys you some time back and costs you hours to get it.

There is also a floor no team size can break: some work is sequential. You cannot test a screen that does not exist, and you cannot design around an API whose behaviour has not been decided.

The four things that actually move the date

Unclear requirements

By a wide margin the biggest factor, and the cheapest to fix. Ambiguity does not stay in the document. It turns into a rebuilt screen in week nine. A week of discovery before the build starts typically narrows the range more than any other decision you can make, because it converts open questions into decisions while they are still free to change.

Integrating into what you already run

A greenfield app answers only to itself. An app that has to work with your CRM, your billing, your warehouse system or your legacy database answers to systems that were not designed for it. Someone else's rate limits, someone else's data model, someone else's downtime.

In our model that work is priced as its own module, 70 to 180 hours depending on how many systems and how well they are documented. Separately, the model multiplies every estimate by 1.25 for the seams between modules: shared state, permissions that cross features, end to end testing and the release cycle that belongs to no module.

Compliance and review cycles

If your product touches health data, payments or public sector procurement, part of your timeline is not development at all. It is waiting for review, then answering questions, then waiting again. Teams routinely plan the build and forget this, which is how a project that was "done" spends another month not shipping.

Decisions waiting on one person

The least discussed and the most fixable. If every design choice needs the founder, and the founder travels, the project moves at the speed of their calendar. Name who decides what before the build starts, and give the team the right to decide the rest.

The part you do not control: store review

Once the app is built, it still has to get through review, and the two stores behave differently.

Apple states that on average, 90 percent of submissions are reviewed in less than 24 hours. In practice that makes iOS review a planning detail rather than a risk, as long as you are not in the other 10 percent.

Google is more open-ended. Its developer documentation says that for certain developer accounts it takes more time, which may result in review times of up to seven days or longer in exceptional cases.

The practical rule: do not schedule a launch event on the assumption that submission equals release. Submit with a buffer, and submit early enough that a rejection costs you a day, not a campaign.

What is not in a development estimate

Estimates cover design, development, QA and release. They do not cover:

• ongoing support and maintenance after launch
• infrastructure and hosting
• third-party licences and paid APIs

None of these are hidden costs. They are just a different budget line, and they continue after the build stops.

How to get a number for your project

The ranges above are how we scope work, not a quote for yours. If you want a number tied to what you are actually building, our cost calculator asks what the product is and which modules it needs, then returns the scope in hours, a realistic timeline and the team it takes. It takes about a minute and does not require a call.

If you would rather describe the project in your own words, tell us what you are building and we will come back with a scoped estimate. The five failures behind most overruns, each priced in hours, are in what actually goes wrong in app projects.

Questions people ask

Can you build a mobile app in eight weeks?

You can build something real in eight weeks, and teams do it every day. What you cannot do is build in eight weeks what was scoped for thirty and call it the same product. If the date is fixed, the honest conversation is about what ships on that date and what waits, not about working faster.

Does React Native make it faster than building twice?

One codebase across iOS and Android removes a large amount of duplicated work, which is why we use it for most products. It does not remove platform work entirely: navigation patterns, permissions and store requirements still differ, and anything that touches the device deeply still gets platform attention. Treat it as one build with platform edges, not as half the work.

Why do two agencies quote such different timelines for the same brief?

Usually because they are not quoting the same thing. One includes QA and project management, the other quotes development hours only. One assumes your API is documented and behaves, the other has integrated with a legacy system before. Ask both what weekly hours per person they planned and what is excluded, and the gap usually explains itself.

What is the single fastest way to shorten our timeline?

Decide the scope before the build starts and stop changing it mid-sprint. Everything else, including adding people, costs more than it saves.