How Long Does It Take to Make an App?

The mobile app market looks juicy to a tech entrepreneur – or an entrepreneur from any industry, for that matter. With researchers expecting the mobile app market to grow to $189 billion by 2020, trying to get a piece of the market by building and scaling an app is a tempting proposition.

Unless you’re already familiar with the mobile app landscape, however, it can be difficult to know where to start. Building an app is often a long, arduous process. Between building out feature lists, determining target user demographics, and managing the actual development process, building a mobile app is often a longer process than many people realize. But just how long are we talking, specifically?

Unfortunately, that’s a hard question to answer.

"When my clients ask me how long development will take, I tell them it's like asking how long it takes to write a book," explains Ben Lee, founder of the app development agency Rootstrap. "A 100-page young adult novel might be quick to write. But if you’re looking for Proust, it's going to take a while."

The problem is that fundamentally, not all apps are created equal. Mobile apps very widely in functionality, capabilities, and the technology involved – and these factors can dramatically influence how long the app takes to build. At the most basic level, though, the biggest determinant of an app’s development timeline is the feature list.

A feature list outlines all the functionalities of a finished app: it explains everything the code needs to be able to do before the app can be called complete. Some apps are simple enough to have only one feature: the flashlight app, for example, simply turns a phone’s camera light on and off. Others, however, have remarkably large and diverse feature lists, allowing users to create profiles, send messages, use geo-based features, and a slew of other possible functions.

How long it takes to make an app depends directly on the length and complexity of the feature list. The fewer features and the simpler those features are, the faster it’ll be to develop the app. But as the features pile up, and the more involved those features are to code out, the longer it’ll take to build.

While Lee cautions that it’s difficult to make a blanket statement for how long it takes to build an app, he says that most apps take between 4 and 6 months to build. The simplest, most bare-bones apps could take only a few weeks to code, while behemoth apps could take as long as a year – but most fall in the 4-6 month range.

Beyond feature list and functionality, another major factor for how long it takes to build an app is the actual team building it. There’s wide variance in the speed, skill, and quality of app developers, and both the size and experience of your team will affect how long it takes to build an app.

According to Lee, his 4-6 months estimate was based on a team of 2-4 full-stack engineers working a normal workweek. However, the same app can take more or less time to build depending on the size, skill, and dedication of the team building it – for better or for worse. A larger team may mean your app gets built faster, but if the engineers are rushing through the coding so they can finish development and move on to the next project, that extra speed could mean you’ll face bugs and other issues down the line. When it comes to app development, speed isn’t everything.

Finally, there's one factor that can turn even simple apps into a massive undertaking: the technology involved. In particular, any functionality that requires server-side technology can dramatically increase the time needed to finish the build.

As explained on the Rootstrap Blog, even a seemingly-simple app like Toggl may take months to build due to the server-side technology required. Toggl is relatively basic in its functionality: it's a time tracking app that lets users track time by category. It's essentially a souped-up egg timer. It should be a quick build.

But Toggl lets users create an account and sync their time data across devices. This means that even though the feature list is pretty bare, Toggl requires back-end servers to store and manage the data – and that adds a whole new layer to the development process. Building an app like Toggl requires engineers to write code for the servers as well as the app itself, almost like building two apps instead of one. This can make an app that would otherwise take a month to build end up taking several months to develop. And if the feature list is more extensive, development could run well over 6 months.

The moral of the story here is that there's no way to determine how long it takes to build an app without also considering the requirements for finished development.

The "average" mobile app will take anywhere between 3 and 6 months to finish. But depending on the length of the feature list, the complexity of the tech involved, and the team working to build it, that timeline could be one month, 12 months, or anywhere in between.