PPI Calculator

The PPI Calculator helps you determine the pixels per inch (PPI), dots per inch (DPI), and display size for any device.

It also allows you to calculate DPI, which refers to the number of printed dots within one inch of an image produced by a printer.

What is the PPI Formula?

To calculate PPI (Pixels Per Inch), divide the length of the diagonal in pixels by the length of the diagonal in inches. You can also use an online PPI calculator for instant results.

PPI Formula:

\[ \text{PPI} = \frac{\text{Diagonal in Pixels}}{\text{Diagonal in Inches}} \] \[ \text{PPI} = \frac{d_p}{d_i} \]

Formula for Diagonal Length in Pixels:

\[ d_p = \sqrt{\text{Width}^2 + \text{Height}^2} \]

Where:

• d_p = length of the diagonal in pixels
• Width = width of the screen in pixels
• Height = height of the screen in pixels

How to use the Pixel Per Inch Calculator:

Don’t to worry; our pixel density calculator is fully loaded with a user-friendly interface. You just have to follow these steps to get ppi and dpi resolutions.

Inputs:

• First of all, you have to enter the screen width in (Pixels) in the field of ‘Horizontal regulation.’
• Right after, you ought to enter the screen height in (Pixels) in the field of ‘Vertical Resolution.’
• Very next, you have to enter diagonals screen size in (inches) in the field of ‘Diagonal Screen Size.’
• After this, select your device from the dropdown of this pixel calculator either it is a computer, phone or a tablet.
• Finally, hit the calculate button of this screen dpi calculator and get the Pixels Per Inches (PPI), Total Pixels, and Dot Pitch.

Outputs:

• Pixel Per Inch (PPI).
• Dot pitch.
• Display size.
• Total pixels of screen.
• Pixel per square inch (PPI2)
• Diagonal length.
• Aspect ratio.

How to Calculate PPI Manually (Step-By-Step)

To calculate PPI, first determine the number of pixels along the diagonal:

\[ d_p = \sqrt{\text{Width}^2 + \text{Height}^2} \]

Where:

• Width = horizontal pixels
• Height = vertical pixels

Then apply the PPI formula:

\[ \text{PPI} = \frac{d_p}{d_i} \]

Where:

• d_i = diagonal screen size in inches

Example:

Screen resolution: 1800 × 900 pixels
Diagonal size: 20 inches

Step 1: Calculate diagonal pixels

\[ d_p = \sqrt{1800^2 + 900^2} \] \[ d_p = \sqrt{3240000 + 810000} \] \[ d_p = \sqrt{4050000} \] \[ d_p \approx 2012.46 \]

Step 2: Calculate PPI

\[ \text{PPI} = \frac{d_p}{d_i} = \frac{2012.46}{20} \approx 100.62 \]

The screen has approximately 100.62 PPI.

References:

From the source of Wikipedia: Pixel density, Basic Principles, Outputting to a Different Device, Printing on Paper, and much more about PPI.