How To Measure a Computer Screen?

The diagonal distance from one top corner to its opposite bottom corner of a screen is described as the size of a screen. The bezels of the display are excluded when measuring a screen. The screen size is measured in inches and it differs from screen resolution, which is measured in pixels.

The easiest way to find out the size of your screen, whether it be a monitor, laptop, tablet or a mobile phone, is to either look for it in the manual or type the model or make of your device on any search engine and you can easily find detailed specifications of the device.

If everything else fails, there are two simple ways of measuring the size of a screen.

The first one involves using a measuring tape or a meter ruler (a half-meter ruler should work as well). In this method, you start measuring diagonally from the top right corner all the way to the bottom left corner or vice versa. The diagonal length from either the top right corner to the bottom left or the top left to the bottom right would be the size of your display. While doing so, it should be kept in mind that the bezels or casing around the screen should not be measured along the screen.

The second method does involve a bit of mathematics. In this method, we make use of the Pythagorean theorem. The Pythagorean theorem states that in a right angled triangle, the sum of the squares of the Perpendicular and Base are equal to the square of the Hypotenuse, which in this case is the diagonal length (also known as the size of the screen). This can all be summed up in the diagram below.

All you need to do is, measure the width and height of the screen (excluding the bezels of course), then you apply the Pythagorean theorem by taking the squares of both the width and height of the screen and add them together. You then calculate the square root of the sum and the answer would be the screen size of your display.

The following example should help to clear things out.

The height and width of the Dell Latitude E5440 screen is 6.9 inches and 12.2 inches respectively. You start by taking the squares of the height and width, which are 47.61 and 148.84, then you add them together to get the sum 196.45. You finish by taking the square root of the sum which is 14.01 inches. The advertised screen size of the Dell Latitude E5440 is 14 inches.

Note: If you choose to carry out the second method, it should be kept in mind that the answer would only be as accurate as your measurement.

However if you don’t intend on carrying out all of these calculations, you can simply type the words ‘Pythagorean theorem’ on any search engine, the results should show you a calculator, which would calculate the Hypotenuse (in this case the size of your screen) just by typing in the length and width of the device.