1 inch = 2.54 cm. Usually, the number of inches of a display screen is calculated by measuring the diagonal length of the light-emitting part of the screen.
So 2.2 inches means the diagonal of the screen is 5.588 cm? . 2.5 inches means the diagonal of the screen is 6.35 cm. 3.8 inches means the diagonal of the screen is 9.652 cm.
Extended data:
Mobile phone screen size conversion:
The conversion of mobile phone screen size is based on Pythagorean theorem. That is, the sum of the squares of two right angles is equal to the square of the hypotenuse. The ratio of two right-angled sides can be calculated according to their respective ratios.
For example, for a full HD screen of 1920* 1080, the ratio of two right angles is 16: 9.
16? +9? = 18.36?
The length of the 4.7-inch mobile phone screen: 4.7× 2.54÷18.36×16 =10.40 cm.
Width of 4.7-inch mobile phone screen: 4.7× 2.54÷18.36× 9 = 5.85cm.
References:
Phoenix Net-With the advent of the full-screen era, how to calculate the screen size?
Baidu encyclopedia-inch