The first iPhone with a 4-inch screen debuted in 2012: it was the iPhone 5. Apple announced the device on September 12, 2012, and began selling it in the United States and several other markets on September 21.
The iPhone 5 expanded the display from the 3.5-inch screen used by every previous iPhone to a taller 4-inch Retina display. Its resolution increased to 1136 by 640 pixels while preserving the same pixel density, giving the phone an extra row of icons and a 16:9 screen ratio suited to widescreen video.
The model also introduced Apple’s Lightning connector, replacing the long-running 30-pin dock connector. It used Apple’s A6 chip and supported faster cellular data through LTE. Later models, including the iPhone 5s and iPhone 5c, retained the same 4-inch display, but the iPhone 5 was the first to introduce that screen size to the lineup.