How much does it cost to build a mobile app, and do you actually need one?

The question before the price: do you need an app at all?

An app is a program someone downloads from an app store and installs on their phone. A website is something they open in a browser. Modern websites work beautifully on a phone, can be saved to the home screen like an app, and cost a great deal less to build and run. For most ideas, that is what people actually want.

You genuinely need a real app only for a few things: when it has to work offline, use the phone's hardware deeply, send a steady stream of push notifications, or when being in the app store is itself the point. If none of those apply, a website that shines on mobile will do the job for far less, and there is nothing to download, which is one less reason for someone to say no.

Why apps cost what they do

Apps are expensive for reasons that are easy to miss. You are often building the same thing more than once, because phones come in two families that do not share. There is the store approval process to satisfy. And an app is never really finished, because every time the phone makers push out a new version, your app has to keep up or it starts to break.

That last point is the one people underestimate. An app is not a thing you buy. It is a thing you keep.

Rough figures

• A website that works superbly on a phone, which is what most 'app' ideas really need: in the range of a normal website, often £1,500 to £8,000 depending on what it does.
• A genuine app doing something a website cannot: a bigger commitment, usually five figures once you include both phone families, the store process and the first year of keeping it alive.

If someone quotes you a few hundred pounds for 'an app', be careful. Either it is a website in disguise, which might be exactly right, or it is a corner being cut that you will meet again later.

The commitment nobody mentions

The build is only the start. A real app needs ongoing upkeep just to keep working as phones change underneath it, plus the store fees to stay listed. Budget for the app to keep costing something every year, not just once. If you are not ready for that, it is a strong sign a website is the wiser route for now.

So what should it cost?

For most people the honest answer is: less than you think, because you probably need a superb mobile website rather than an app. For the few who genuinely need an app, considerably more, with an ongoing commitment to match. The cheapest possible mistake is building a full app when a website would have done. The way to know which you need is to talk through what it actually has to do.