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Calculate PPI - it's that easy

in Hardware
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Calculate PPI yourself using a formula
Calculate PPI with an online tool

This article shows you how to calculate the pixel density of a screen..

A high resolution does not necessarily mean that the picture looks razor sharp. A 4K screen does not automatically have a better picture than a WQHD monitor. The decisive factor here is the ratio between the number of pixels and the size of the screen. The PPI value is used for this. This states how many pixels there are in one inch (pixels per inch). In this article we will show you how you can easily calculate the PPI value yourself.

### Calculate PPI yourself using a formula

To calculate the PPI, you will need the following information:

• Screen resolution in pixels (width x height)
• Screen diagonal in inches

The formula for calculating the PPI is simple: PPI = number of pixels on the screen diagonal divided by the screen diagonal in inches.

The Pythagorean theorem is used to calculate the pixels of the screen diagonal:

Number of pixels on the screen diagonal = root of: (horizontal pixels) ² + (vertical pixels) ²

With a resolution of 1920 x 1080 pixels, the calculation results in a number of pixels 2203 on the diagonal.

This value divided by a screen diagonal of 24 inches results in a pixel density of approx. 92 pixels per inch.

### Calculate PPI with an online tool

If you don't want to do the math yourself, you can use a handy online calculator to calculate the pixel density. In our example we are using Retracked's PPI calculator .

The calculator is clearly structured, you only have to specify the diagonal of your screen and the resolution. There is also a quick selection for the most common screen resolutions. To then calculate the pixel density, simply click on " Calculate pixel density ". You should not confuse PPI with the so-called DPI . This value also indicates the "dots per inch", but in contrast to the PPI value, it relates to print media..

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