Calculations with Optical Instruments
Calculate the Resolution and Pixels per Inch or cm of a Monitor
Calculator for the number of pixels in a certain length or height on a screen. Enter the width and height of the screen and the resolution and calculate, how many pixels are in an inch or centimeter or in any length (default 10 inches). ppi, pixel per inch, is the common unit for the pixel density of a monitor.
Example: A screen is 70 centimeters wide and 39 centimeters high. It has a resolution of 3840 by 2160 pixels. The pixel density (ppi) is then approximately 140, with a slight variation in length and height. There are 55 pixels per centimeter, and each pixel is slightly less than half a millimeter in size. This applies to a scaling of 100 percent. If the scaling is set to, for example, 150 percent, then there are only 37 pixels per centimeter, with a pixel size of just under 0.7 millimeters.
Screen resolution has steadily improved over time, allowing for sharper images. However, if, for example, a font size is specified in pixels, the pixel size decreases with increasing resolution, and consequently, so does the size of the letters, making them smaller and therefore harder to read. Therefore, it is possible to adjust the scaling to ensure legible and recognizable content on the screen. The default scaling is 100 percent. Increasing this value increases the letter size accordingly. At 200 percent, the letters are twice as large.
Even though this calculator outputs fractions of pixels as mathematical results, these cannot be displayed on the screen. A pixel is always displayed completely or not at all. However, there are tricks to make individual pixels appear smaller. For example, a gray pixel on a white background appears smaller than a black pixel. But this effect has nothing to do with the calculations used here.