What does PPI mean?

Pixels per inch is the image resolution unit, the higher the image PPI value, the more details of the picture will be richer, because the number of pixels per unit area is more, so the picture taken out by the digital camera because of brand or production time may be different, common have 72ppi,180ppi and 300PPI, This is the default.

(27-inch Imac,ppi with 5K resolution up to 217)

When your cell phone screen is 10-12 inches (about 25-30 centimeters) from your eyes, its resolution can be as long as the magic number 300PPI (300 pixels per inch) is above, and your retina will not be able to distinguish pixels, such a screen called "Retina screen". Because of its extremely high pixel density, the screen display is unusually clear and sharp. In general, computer display screen resolution is 72PPI. If you want to know if your phone has a "retina (Retina) screen," Calculate the PPI on your phone's screen.

(1080P (upper) and 2K contrast)

The formula for PPI expression is ppi=√ (x²+y²)/Z (X: length pixels; Y: width pixels; Z: Screen size). The calculation formula is shown below.

Currently on the market the most PPI several mobile phones:

Moto Droid Turbo uses a 5.2-inch 2560x1440 Super AMOLED screen with a PPI of 564.

The IPhone 6 and 6 Plus use 4.7-inch 1334x750 and 5.5-inch 1920x1080 IPs screens, with PPI 325 and 400 respectively.

The Samsung Galaxy Note4 employs a 5.7-inch 2560x1440 Super AMOLED screen with a PPI of 515.

Nexus 6 uses a 5.96-inch 2560x1440 Super AMOLED screen with a PPI of 492.

Iuni U3 uses a 5.5-inch 2560x1440 ips screen with a PPI of 538.