We have covered and written about the issues enterprises need to consider when planning to develop a mobile app, especially on choosing between native apps, mobile web apps (HTML5, etc.), or a hybrid approach that includes elements of each. And have discussed some of the choices / factors that would have an effect on the time required to bring an app to market, but made no attempt to advise or speculate on how long it should take to “develop a mobile app”. This is not a question with a straightforward answer as any software development manager will tell you.

There are many reasons estimating app development time is difficult, but there are also items outside of actual coding that need to be accounted for. For example, a key factor often not considered in measuring app development is the time involved to train or hire for skills. Since most organizations already have experience with standards such as HTML and CSS developing mobile web apps should be, ceteris paribus, less costly and quicker than developing a native app. This is especially true when the app needs to run on multiple devices with different APIs using different programing languages on multiple mobile (and possibly forked) operating systems. But there are often appealing device features that require native code expertise, and even using a mobile development framework which deals with most of this complexity requires learning something new.

App development schedules can also be at the mercy of app store approvals and not-always-predictable operating system updates.

As unlikely as it is to come up with a meaningful answer to the catchy (and borrowed) title of this post, executives need good estimates of the time and effort in developing specific mobile apps. But experience in developing mobile apps is still slim in many organizations and more non-technical managers are now involved in approving and paying for app development. So even limited information on length of effort can provide useful data points.

I found the survey that informed the Visual.ly infographic below via ReadWrite at How Long Does It Take To Build A Native Mobile App? [InfoGraphic]). It involved 100 iOS, Android and HTML5 app developers and was done by market research service AYTM for Kinvey, provider of a cloud backend platform for app developers.

Their finding? Developing an iOS or Android app takes 18 weeks. I didn’t see the survey questions so don’t know whether whether 18 weeks was an average of actual developments, opinions on what it should take, or something else.

Of course there are simple apps that can be created in a few days and some that will take much longer, but in either case the level of effort is almost always underestimated. Even with all the unanswered questions about resources etc., the infographic raises, the 18 week finding may helpfully temper somebody’s overly optimistic expectations.