# Pixels Per Inch PPI Calculator

## Calculator Use

The PPI Calculator finds pixels per inch and pixels per centimeter. PPI is a measure of pixel density or resolution of a computer screen, television screen or other display device. Pixels per inch or PPcm indicates how many pixels are in a 1 inch line or 1 cm line on a display.

## Follow These Two Steps to Calculate PPI:

- Use the Pythagorean Theorem to calculate the diagonal length in pixels

\( diagonal_{pixels} = \sqrt{width^2 + height^2} \) - Use the formula to calculate PPI, dividing the length of the diagonal in pixels by the length of the diagonal in inches

\( PPI = \dfrac{diagonal_{pixels}}{diagonal_{inches}} \)

The number of pixels per inch or PPI tells you how many pixels are in a 1 inch line on a display screen. The PPI will be the same whether it's a horizontal or vertical or diagonal inch because pixels are square and therefore symmetric. If a display does not have square pixels then this calculator does not apply.

You can use the same PPI formula above to calculate pixels per centimeter, PPcm. Just substitute cm for inches to find PPcm.

## How to Calculate PPI^{2} or Pixels per Square Inch

Multiply PPI × PPI to get pixels per square inch. The number of pixels in a square inch represents the resolution or pixel density of an area of one square inch. Substitute 1 cm for 1 inch to find pixels per square centimeter or PPcm^{2}.

## Example: Calculate Pixels per Inch PPI

You have a computer screen that is 1920 pixels wide by 1080 pixels high. The diagonal is 10 inches. You want to find the pixel density in one linear inch of display.

**Calculate the diagonal length in pixels with the Pythagorean Theorem:**

*diagonal _{pixels}* = √(1920

^{2}+ 1080

^{2})

*diagonal _{pixels}* = √(3686400 + 1166400)

*diagonal _{pixels}* = √4852800

*diagonal _{pixels}* = 2202.91 pixels

**Now divide:**

PPI = *diagonal _{pixels}* /

*diagonal*

_{inches}PPI = 2202.91 / 10

PPI = 220.29 pixels

So there are 220.29 pixels in a 1 inch line on the display.

## Example: Calculate Pixels per Square Inch, PPI^{2}

Using this same computer screen, PPI^{2} will be:

220.29^{2} = 48528 pixels per square inch

So there are 48528 pixels in an area of the screen that is 1 inch wide by one inch high.

**Cite this content, page or calculator as:**

Furey, Edward "Pixels Per Inch PPI Calculator"; from *https://www.calculatorsoup.com* - Online Calculator Resource.