How to measure the diagonal of a TV: determining and choosing the screen size in centimeters and inches
When planning to buy a TV, we often wonder what size TV is right for our living room or bedroom?
This is often difficult, because the diagonal of TVs in most cases is measured in inches.And to find out how much space the TV will take in our interior, we have to convert inches to centimeters.
We recommend that you read our guide, which will detail how to measure your screen size, how to choose the right TV size for your room, and how far from the sofa it should be placed.
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Why measure the diagonal of the TV
Choosing a TV is an important decision in the sense that it's not something you change out every two years. If you have a TV, chances are you'll keep it for at least the next five to ten years.
When planning to buy a TV, you first need to analyze where you plan to place it and at what distance you will use it.
For large spacious rooms, such as the living room, where the device will be used by many people at once, it is worth choosing larger TVs that guarantee excellent visibility even from the farthest corners.
In turn, in a small bedroom, models with smaller screen sizes are required, however, in this case, their resolution will also matter. In addition, it is very important to consider the distance from the sofa or bed to the TV so that you can watch movies and TV programs without straining your eyes.
Thus, the correct choice of diagonal is of key importance when buying a TV.
Knowing this size is necessary so that you can understand how much space the screen will take up in the room where you want to place it.. Or, conversely, use the space you have in the room to choose the screen size.
How to measure the diagonal of a TV using different methods
The size of a TV screen is measured by its diagonal.
The diagonal is traditionally expressed in inches, less often in centimeters. The ratio between the two units is 1 inch by 2.54 centimeters.
Some people mistakenly believe that, for example, a size of 32 inches is the width of the device, that is, the distance of the entire TV from left to right. But it's not actually a distance, 32 inches or 81 cm in this case is the distance from the top corner of one side to the bottom corner of the opposite side and vice versa.
Thus, the TV diagonal is measured from the upper left corner to the lower right corner of the TV (or, conversely, from the upper right corner to the lower left corner).
Many users make one very gross (especially in the case of embedded technology) mistake when measuring the corners of the device case.
The resulting figure will be erroneous, since the frame may be thicker, larger, smaller, and sometimes completely absent. In the latter case, there will be no problems, but in other cases you will receive incorrect information.
Convert centimeters to inches
While CRT TVs were measured in centimeters, the transition to LCD screens, driven by some English-speaking countries that still use imperial units, has largely shifted most international corporations to measure in inches.
In general, it is so accepted that the dimensions of TVs are always indicated in inches. For most Russians, this unit of measurement means little. Therefore, in order to visualize the size of the screen in your head, you should do a little calculation and convert inches to centimeters.
One inch equals 2.54 cm. It is not difficult to calculate that a 32-inch TV has a screen diagonal of 81.28 cm, and a 49-inch TV has a diagonal of 124.46 cm.
You can also count vice versa. To find out the diagonal of a TV in international terms, you just need to measure the diagonal of the screen (still in centimeters) and divide it by 2.54 and you get the diagonal in inches.
Diagonal measurement using the metric system also allows you to get a result in centimeters. To calculate the result in inches, simply multiply this value by 0.393701.
How to determine the right TV size
When choosing a TV, it is very important to measure with a tape measure the distance at which the TV will be placed from your chair, sofa or bed.
In the case of Full HD TVs, a reasonable solution is to adjust the diagonal length of the TV to about one third of the distance separating the viewer from the screen. To do this, you can use the following ratio: distance from the TV 4.2 cm per 1 inch of screen diagonal.
It is also worth remembering that in the case of 4K Ultra HD TVs, this coefficient will be much lower: 2.1 cm per 1 inch of screen.
- The small 32-inch TV is ideal for a bedroom, nursery or other small room where space is limited. A screen with such a diagonal can easily replace your monitor, so it will also be appreciated by those who like to spend time playing games. For the most comfortable viewing experience, the distance from the 32 inch Full HD TV to the viewer's eyes should be approximately 145 cm.
- A medium-sized TV with a screen size of up to 43 inches is suitable for medium-sized children's rooms and living rooms. If you like to watch movies until late at night, it is also suitable for the bedroom. For optimal viewing comfort, be sure to maintain adequate distance between the TV and the bed or sofa. In the case of the 40-inch Full HD model, this distance is 170 cm.
- It is believed that large TVs (48-65 inches) are ideal for large rooms. But even if the room does not have a large area, this does not mean that you have to give up a large TV. 65 inches is certainly a lot, but it is a myth that a TV with such a diagonal cannot be placed in a small apartment. Of course, installing a large TV with FullHD resolution can be difficult, but a 4K TV with such a diagonal will fit perfectly. The high picture quality also means that it can be placed closer to the sofa, allowing you to watch movies with excellent picture quality from a short distance of 103 cm to 206 cm.
What screen aspect ratio to choose
Another question that needs to be asked when buying a TV is the choice of aspect ratio. Which format to choose: 16:9 or classic 4:3?
In fact, there is no definite answer to this question.Each of these systems has its own advantages, and any choice one way or another will be a compromise.
Until recently, televisions sold only had a 4:3 screen. This is a typical television format, it resembles a square and is inconvenient at a close distance from the viewer's eyes, the 16:9 format works much better here.
The fact is that our eyes have a much larger viewing angle in the horizontal plane than in the vertical one. This was noticed at a time when the popularity of cinema began to decline in favor of television (the first films were in 4:3). That's when they started making big-screen films.
Of course, there are other movie formats, such as 2.35:1, 1.85:1. In practice, every panoramic movie is recorded in aspect ratios other than 4:3.
Most TV broadcasts are broadcast in 4:3 format, and if your TV has this aspect ratio, then the situation is ideal. The problem will arise when you want to watch a full-length movie on such a screen.
As we have already said, modern cinema is fixed in "panorama". Therefore, if you don't want to lose any fragments and fit the whole frame in proportion, you will have to watch a movie with black bars at the top and bottom of the screen.
So what do we end up with?
If you want frames to be displayed on the entire screen, completely preserving the aspect ratio, then we inevitably lose the top and bottom of the image.
If, on the other hand, you want to keep the aspect ratio of the whole frame at 4:3, then vertical stripes will be visible on the right and left anyway. It resembles the letterboxing used in movies, but with the stripes on a different plane.
Thus, in order to fill the entire screen without losing fragments of the frame, you have to sacrifice the correct proportions of the characters. The image will be stretched, which will inevitably lead to artifacts.
What is the best screen resolution
The last criterion in order, but not least, is the choice of screen resolution.
The size and resolution of the TV screen must be related to each other, because, for example, 4K only on a large screen can show all its possibilities. But Full HD is perfectly revealed on equipment with a smaller diagonal.
Similarly, with some features and gadgets, you will get a completely different experience if you watch a movie with 3D glasses on devices of different sizes.
If you have a quality sound system, it will also work great with large TVs, so you'll almost feel like you're in a movie theater.
In other words, you need to consider what goals you are pursuing when buying a TV, in what room and at what distance you plan to watch movies and TV shows.
To choose the right resolution, first determine the room and calculate the required distance.
Next, select the screen size and check which resolution suits you best. The higher it is, the more pixels are displayed on the screen and the more detailed the image.
Although it is worth taking into account the fact that on a high-definition TV, such as UltraHD in combination with the appropriate display standard, a short distance from the TV will not interfere with comfortable viewing of your favorite programs.
Therefore, you can use 4K models in both small and large rooms.
Distance from Full HD TV
Full HD technology is currently the most popular and widespread in home TVs. More than 2 million pixels are responsible for the resolution of 1920x1080.
It is worth remembering that models equipped with such a standard fully reveal their capabilities only when viewed at a distance of about 2 meters. If there is less distance between the sofa and the TV, you should consider an alternative solution.
The most optimal diagonal of a Full HD TV is about 55 inches. For more, 4K Ultra HD resolution is usually recommended.
The optimal distance from the viewpoint for a given resolution is:
- at 46 inches: 193 centimeters;
- at 48 inches: 202 centimeters;
- 50 inches: 210 centimeters;
- at 55 inches: 231 centimeters;
- 60 inches: 252 centimeters;
- at 65 inches: 273 centimeters.
Distance from Ultra HD or 4K TV
Resolution 3840x2160 is referred to as 4K Ultra HD.
The image presented in this format has about 8 million pixels, which is almost four times more than in the case of the Full HD format. Thanks to such a high picture quality, you can and even need to look at the screen at close range.
Examples of the minimum and maximum (at a greater distance from the TV, the differences are physically imperceptible) distances depending on the specific diagonal of the matrix:
- 43 inches: 90 - 181 cm;
- 49 inches: 103-206 cm;
- 55 inches: 116 cm - 231 cm;
- 65 inches: 137 cm - 275 cm;
- 75 inches: 158 cm - 315 cm;
- 82 inches: 172 cm - 344 cm.
If the above assumptions allow you to determine the minimum and at the same time the optimal distance from which the eye can perceive details, it is also easy to determine in which cases it does not make sense to buy a 4K Ultra HD TV.
For example, it is clearly not worth choosing if the diagonal of the matrix is less than 55 inches or if you plan to place the TV relatively far from a chair or sofa.
Useful video
How to measure the diagonal of the TV, see the video story:
