We know that Apple is planning to release two new iPhone models with 4.7-inch and 5.5-inch display. One missing clue is the actual screen resolutions of these devices. Sources recently reported that the iPhone 6 will feature 960 x 1704 resolution, significantly higher than 640 x 1136 resolution used by the iPhone 5S.
So, how can we arrive at the seemingly random numbers? It all started with the original iPhone, released in 2007. The device came with 3.5-inch (320 x 480) display and the company kept this for three generations. The iPhone 4 was an important milestone, it still as the same 3.5-inch display, but with higher 640 x 960 resolution.
It gave us the impressive 326ppi of pixel density, which was something unseen at the time. We could see that Apple doubled the base (horizontal) resolution. Fast forward a couple of years later, the iPhone 5 offered 4-inch display with 640 x 1136 resolution and pixel density remained at 326ppi.
Another obvious pattern is that the company preserved the 16:9 aspect ratio. Now if we triple the base (horizontal) resolution of the original iPhone and keep the 16:9 aspect ratio; the iPhone 6 could have 960 x 1704 screen resolution. There’s an obvious advantage of tripling the original resolution: Developers will find it easier to transition higher resolution. This is equal to 417ppi on 4.7-inch display and 355ppi on 5.5-inch display.
