PPI Calculator

What Is a PPI Calculator?

A PPI Calculator determines the pixel density of a digital display by calculating how many pixels are contained within each inch of the screen. PPI stands for pixels per inch and is commonly used when comparing the density and detail potential of monitors, televisions, laptops, tablets and smartphones.

To calculate PPI, you normally need the display's horizontal and vertical resolution together with its physical diagonal size in inches. This calculator uses those values to determine the diagonal pixel resolution and divide it by the physical diagonal measurement.

Why Use the PPI Calculator?

This free PPI Calculator provides a quick way to determine display pixel density without manually performing the calculation. It supports common screen specifications as well as custom resolutions and physical dimensions.

How to Use the PPI Calculator

Use the calculator to determine the pixel density of a monitor, television, laptop, phone, tablet or other digital display.

1. Enter the horizontal resolution — Enter the number of pixels across the display, such as 1920.
2. Enter the vertical resolution — Enter the number of pixels from the top to the bottom of the display, such as 1080.
3. Enter the physical screen size — Enter the diagonal screen measurement in inches, or switch to the physical-dimensions method and enter the width and height.
4. Calculate PPI — Select Calculate PPI to display the calculated pixel density and additional measurements.

How Is PPI Calculated?

PPI is calculated using the display's horizontal and vertical pixel resolution and its physical diagonal size. First, the horizontal and vertical pixel counts are used to calculate the diagonal resolution using the Pythagorean theorem. The resulting diagonal pixel count is then divided by the physical diagonal screen size in inches.

For example, a 1920 × 1080 display has a diagonal resolution of approximately 2202.91 pixels. If the display measures 24 inches diagonally, its pixel density is approximately 91.79 PPI.

PPI and Screen Resolution

Screen resolution describes the number of pixels available horizontally and vertically, while PPI describes how densely those pixels are arranged across the physical display. Two screens can therefore have the same resolution but different PPI values if their physical sizes are different.

PPI and Display Size

For the same resolution, a smaller physical display has a higher PPI than a larger display. Conversely, increasing the physical size while keeping the same number of pixels reduces pixel density. This makes PPI useful when comparing displays with different dimensions and resolutions.

Understanding PPI Results

A higher PPI indicates that more pixels are packed into each inch of the display. This can allow the display to represent finer details, although perceived sharpness is also affected by viewing distance, display technology, operating-system scaling, image quality and other factors.

PPI is a measurement of pixel density rather than a complete measurement of display quality. A display with a higher PPI is not automatically better in every respect. Brightness, contrast, colour accuracy, refresh rate, response time and other specifications can also affect the overall viewing experience.

Frequently Asked Questions