There was a time just a few years back when the 4-inch screen was considered Apple’s big phone. After five generations of 3.5-inch screens, Apple made the iPhone taller in 2012 with the 4-inch iPhone 5. The width remained the same in a “common sense” move that maintained easy one-hand use for most people, and the 16:9 aspect ratio framed video playback perfectly. Two years later, Apple upgraded the iPhone with two new models: 4.7-inch and 5.5-inch, but no new 4-inch iPhone until now.
iPhone SE is the first upgrade to this size since the iPhone 5s in 2013. It’s a huge specs upgrade
Source: iPhone 6s