Why a 4-inch iPhone makes sense (Hint: not due to Android)

Apple’s next iPhone model will reportedly have at least a 4-inch display according to sources “familiar with the matter” and reported by the Wall Street Journal on Wednesday. Apple(s aapl) hasn’t officially commented, which is expected as the company doesn’t make statements on unreleased products. However, the WSJ has a history of reporting on solid information about future Apple products, possibly as planned leaks from Apple itself. Regardless of where the information came from, a larger iPhone simply makes sense at this point in time.

I recall an online debate I had with my then co-worker Darrell Etherington in February of last year on this very topic: Should the next iPhone have a 4-inch display? Darrell held his own in that back-and-forth, but I believed then — as I do now — Apple can’t stick with a 3.5-inch iPhone forever. Or if it does continue creating phones with that size, they’ll likely be priced lower than a larger model. I even suggested that Apple could use a 4-inch display without increasing the overall size of the device by much, explaining how it would improved the overall experience for both consumption and input:

“Larger screen devices — without much larger form factors, I might add — can provide a better user experience for many: Text is larger as is the software keyboard, for example, as is the media experience, especially as smartphones can play back higher-resolution video. Think of it as moving from a 32- to a 40-inch HDTV set, only on a smaller scale. It’s not really about the screen size, or even about “keeping up with the Androids;” it’s about the improved experience that such a change can bring, and that’s not something you can see from a spec sheet.”

As I said back then, moving to a larger screen on the iPhone has nothing to do with keeping pace of Android(s aap) handsets which are now topping out at 5.3-inch screen sizes. Between mobile apps, web browsing and online video, a larger display that’s still usable with one hand and fits in a pocket is simply more useful. Not everyone will agree, but of course, Apple doesn’t care about the fringe cases: It develops products for the masses with attributes that appeal to most. And if my suspicion is correct, Apple may still keep the 3.5-inch model around at a reduced price from any bigger siblings.

How will Apple accomplish the feat of using a larger display while maintaining its Retina Display definition? My guess is that the phone uses a 1024 x 768 panel which is the same resolution as the company’s first two iPads and works out to 320 pixels per inch. That would allow a 4-inch iPhone to natively run all of the existing iPad applications that aren’t optimized for the new iPad, which is double the resolution in both directions. Thoughts?