The pixel size on the screen and the number of pixels per square centimeter are always different depending on the matrix of the screen. There is a special value - pixels per inch (ppi). From it, you can calculate the number of pixels per mm and cm and vice versa, how many pixels are in a given distance.
Instructions
Step 1
Pixel is not a metric or static value. This is a relative value. Therefore, to calculate the number of pixels in a centimeter, you need to know such a parameter as ppi. It should be noted that the human eye does not distinguish ppi equal to 306 or more. These are such small pixels that the eyeball cannot recognize a single point and perceives the image as a whole. Today, this ppi parameter is used when printing glossy magazines, as well as in Apple iPhone 4 phones.
To measure the number of pixels in a centimeter on any screen, you can use a special table "Pixel Size" located a
Step 2
In the table, you will see the diagonal of the display, its resolution, format, number of pixels per inch (ppi) and pixel size in millimeters.
For example, based on the table, a 21-inch screen with a resolution of 1680x1050 pixels has 94.3 pixels per inch, and the pixel size of such a matrix is 0.27 mm.
This means that 1 cm (= 10 mm) of such a matrix (in length) contains 37.037 pixels (10 mm / 0.27 mm = 37.037). A square centimeter of a matrix of this resolution and diagonal will contain approximately 1371.742 pixels (37.037 x 37.037 = 1371.742).
Step 3
You can also use a specialized calculator if the table does not show the matrix you need. Enter the screen resolution and diagonal in the calculator fields at the top of the page, using a dot as a separator between an integer and its parts, and then click the "Calculate" button. The screen will display such parameters as the visible area of the screen, the aspect ratio, as well as the parameters you need - the pixel size in millimeters and the specific resolution.
Next, also divide 10 mm (1 cm) by the pixel length to convert centimeter to pixels. If necessary, multiply the result by the number of centimeters.
