The question of the diagonal of the laptop screen is debatable. Many manufacturers do not indicate the actual size, but the rounded number of inches. Therefore, a laptop passport will not help much here. Now we will try to describe several ways that will help us figure out how to find out the diagonal of a laptop (in real dimensions). It is worth considering that the actual number of inches may differ greatly from the declared one.
Most manufacturers tend to round diagonals up. But some still honestly inform users about screen sizes. The only problem is that there are very few such companies. Well, let's get down to finding out the actual screen size.

If accuracy is not needed
If you are not interested in the exact size of the screen, you can refer to the documentation of the mobile PC. The diagonal will be indicated in the technical specifications. Some manufacturers supply the case of their devices with special stickers describing the main technical characteristics. The diagonal of the screen can also be indicated there. If not, we turn to the instruction manual and look for a section with characteristics in it.

Mostusers enough generalized information about the diagonal of the screen. However, some laptop owners want to know more. For example, the general inscription "17 inches" does not suit them. And this is correct, since it can be either less or more than the declared figure. Now let's move on to how to find out the diagonal of a laptop using simple measurements.
Using a ruler
Since our country uses the metric system of measurement (meters, centimeters, millimeters), and laptop screen sizes are in inches, you will not only have to measure the diagonal, but also calculate the required number of inches using a simple formula.

The screen should be measured from corner to corner along an inclined line. That is, the diagonal is the line between the two farthest corners of the screen. The main thing is not to confuse. There is nothing complicated in the measurement procedure itself. And you will see this now.
So, put the ruler on the screen and start measuring the visible part of the screen. Then the resulting number must be divided by 2.54 in order to convert centimeters to inches. Now you will get the actual screen size. For example, if you get 43, 18 in centimeters, then by simple division we calculate that the real screen diagonal is 17 inches. Continue in the same vein.
Search engines
The question of how to find out the diagonal of a laptop has one more answer. You can refer to the rich reference material on the Internet. It is enough to drive the laptop model into the Yandex search box, and the system will give you a huge number of results withdetailed description of technical characteristics. However, it is very difficult to find out the actual screen size in this way. In this way, only general information can be obtained. But if you stumble upon some site for detailed study of laptops, then it is possible that local "specialists" have examined your model inside and out and provide reliable data.
However, you should not rely too much on the data of the Network. Not all sites check the veracity of the information provided. To obtain the most accurate data, it is better to use the official websites of the device manufacturer directly. This is where you can find the most accurate and complete information about your laptop and its screen.
What is the exact screen size for
First of all, you need to know the real size in case of failure of the laptop display. To replace this element, it is strongly not recommended to be guided by general data. There are cases when users, guided by the inscriptions on the box, ordered a new matrix, but it did not fit, because it was more or less than what was needed. Accuracy is important here, and general information will not do.

Some need to know the actual size out of pure curiosity. It is always interesting to find out how unscrupulous manufacturers are and how many inches they deceived users. Although this happens quite rarely.
Conclusion
Now the question of how to find out the diagonal of a laptop disappears. And if the screen of your device fails, you can easily measure the old one and ordernew. There is nothing difficult in this. Yes, and for self-education it is useful to know how inches are counted in diagonals.