How to find Pixel Density (PPI) of a screen?
PPI (Pixels Per Inch) is the measurement of the pixel density (sharpness) of any display screen. It is used in the measurement of screen resolution of electronic devices like computer, mobile phones, television etc., Here is a simple step by step tutorial to measure the pixel density of the screen.
Formula :
Pixels per inch (PPI) = dp / di
dp = √ w2p + h2p
Where,
dp= Diagonal resolution
wp = Width of the screen
hp = Height of the screen
di = Diagonal Size (in inches)
Example: Consider a 21.5 inch LCD TV with the screen resolution of 1024 x 768. Find the PPI of the LCD.
di = 21.5 inch
wp = 1024
hp = 768
Step 2: Find dp (Diagonal resolution) of the LCD.
dp = √ w2p + h2p
= √(1024)2 + (768)2
= √ 1048576 + 589824
Step 3: Diagonal Resolution = √ 1638400
Step 4: We got the Diagonal Resolution as 1280
Step 5: To find the pixels per inch of a LCD, substitute the obtained values in the formula.
PPI = dp / di
=1280/21.5
Step 6: Pixels Per Inch / Pixel Density = 59.5