How to measure Monitor size?

There are several ways of finding out the actual size of your LCD. LCDs are measured diagonally and usually only the viewable area is counted.

Place the end of your tape measure in one of the corners and align the tape with a diagonal corner on the opposite side. Note the size in inches. Diagonal size is your monitor size.

Another short way of finding the exact size of your LCD is to remove it from the computer and look at the model number sticker on the back. Virtually all LCD model numbers contain the physical size of the LCD in inches. In this case, my LCD model number is LTN156ATO1, the number 156 means that the LCD is 15.6″ (fifteen point six inches) diagonal.

Please note, sometimes the screen size of your device can be found on product stickers its box, or its manual in our experience this information is usually correct. Also, you can get the monitor size from the product specifications on the official website. But there were cases where the size was misstated in official documentation which resulted in extra hassle for customers.

Please, try to physically measure your original LCD whenever possible.

How to measure a Monitor Screen manually?

Below we will explain with an article how to correctly measure the size of your computer/laptop monitor, whether you’re just curious about the size of your existing monitor or you’re ready to purchase a new one. It is important to know how to accurately measure the size of your screen.

Here we are using a tape measure or a simple mathematical equation

Method #1: Measure Monitor Size With a Measuring Tape

1. Take a sufficient length of measuring tape.
2. Start to measure the diagonal of the screen. Basically a diagonal measurement from one corner of the screen to the opposite corner of the screen, either the lower left to the upper right or upper left to the lower right. [Measure only the screen and not the bezel (the plastic edge) or the casing around the screen.]
3. The diagonal scale of the monitor is the actual size of the monitor.

So, in this case, my screen diagonal is 18.4 inches and that is the size of the computer monitor although you can also take the horizontal measurement or the vertical measurement of the monitor those really don’t have any meaning, the actual computer monitor size is a diagonal measurement.

Method #2: Measure Monitor Size With Simple Math

Measure a monitor screen size alternative method is the Pythagorean theorem. It’s called a right-angled triangle in which the hypotenuse side is equal to the other two sides. The hypotenuse side measurement equal is to the computer monitor size.

Now measure your monitor width and height and square each, and calculate the square root of the sum. The result is your monitor size.

For example, my laptop monitor screen width is 16 inches, and height of 9 inches.

square of width, (16)² = 256

square of height, (9)² = 81

The two numbers sum is = (256+81) = 337

Now, calculate the square root of the sum (√337) = 18.4

18.4 inches is the monitor screen size of my laptop.

Resolution based on LCD monitor size

Monitor size	Recommended resolution (in pixels)
19-inch standard ratio LCD monitor	1280 × 1024
20-inch standard ratio LCD monitor	1600 × 1200
20- and 22-inch widescreen LCD monitors	1680 × 1050
24-inch widescreen LCD monitor	1920 × 1200

Laptop screen size	Recommended resolution (in pixels)
13- to 15-inch standard ratio laptop screen	1400 × 1050
13- to 15-inch widescreen laptop screen	1280 × 800
17-inch widescreen laptop screen	1680 × 1050