The Apple iPhone 5s features a resolution of 640 x 1136, while earlier rumors had the iPhone 6 weighing in at 960 x 1704. If Apple is planning on using the same resolution for both the 4.7 inch and 5.5 inch variants of the iPhone 6, this would mean a smaller pixel per inch (ppi) pixel density reading on the phablet version of the device. Let's take a look.
At 4 inches, the Apple iPhone 5s has a pixel density of 326ppi. A 4.7 inch Apple iPhone 6, with a resolution of 828 x 1472, would combine to produce a pixel density of 359ppi. The same resolution on a 5.5 inch iPhone phablet would work out to a 307ppi pixel density. Both new screens would surpass the 300ppi benchmark that Apple uses to give a display the title of a "Retina display." The two figures are well below the 538ppi pixel density on the LG G3, the first phone in the states to offer a 1440 x 2560 QHD resolution screen. Most 5 inch Android phones with a 1080 x 1920 resolution, like the HTC One (M8), sport a 441 ppi pixel density.
The answers to all of your questions about the Apple iPhone 6 should be answered on September 9th, when Apple is holding an event during which it is expected to unveil the next iteration of its iconic smartphone.
This iOS 8 file found in the Xcode 6 SDK beta for the iPhone, supposedly reveals the resolution for the 4.7 inch and 5.5 inch iPhone 6 screens
source: 9to5Mac via BGR