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Understanding TV Viewing Distance and Flat Screen HDTV Sizes

There are two questions that are commonly asked by people when they are buying new HD flat screen TVs; what screen size do I need for my room and what is the best TV viewing distance?

The fact is that these two things are closely related, and the answer you get for one question will have an effect on the other.

Regardless of whether you are buying an LED or OLED TV, one of the great things about a flat panel TV is that they are available in screen sizes much larger than a traditional CRT TV. They can easily be hung on a wall or stood on a piece of furniture, as they are much thinner and lighter.

However, because we are not used to these big screen TVs, it can be difficult to decide which size is best for the room and where we should position the screen. Do we just buy the largest screen we can afford, or is it possible to get a screen that is just too darn big for the room?

So, are there any guidelines we can use to decide on the right screen size for our room? Let's take a look.

How Is the TV Screen Size Measured?

The size of a flat screen TV is usually measured on a diagonal line from the top left corner down to the bottom right corner. Or, bottom left to top right if you prefer.

Hopefully it's the same!

This distance is often quoted in inches, and different manufacturers will offer slightly different sizes in their product range.

When measuring, you can ignore the bezel around the edge of the TV (the 'frame' of the television). In older flat screen TVs the bezel used to be fairly large. However, modern TVs have a much smaller frame, so almost all of the distance will be the screen anyway. 

TV Screen Size

Currently, there are two main types of TV - an LED and an OLED TV. You might be surprised to know that these two different types are available in very different screen sizes.

You can expect to find LED TVs ranging from about 15 to 80 inches. And, in some cases, more. However, at the time of writing, OLED TVs are only available in larger screen sizes. Usually around 55-inch to 75-inch.

So one thing you need to understand is that the size of the screen you buy may be limited by the type of technology you want.

If you are interested in understanding more about the differences between LED and OLED televisions, check out my guide to the best OLED and LED flat screen TVs in 2018.

However, once you have decided on the type of HDTV that you want, how do you choose the right screen size for your room and the best placement position?

Finding the Best Screen Size and TV Viewing Distance

The first thing to appreciate here is that this isn't an exact science.

Personal taste, the location in the room, the resolution of the TV pictures you are watching and even the quality of your eyesight can affect your opinion of the right size of TV for your room.

You can put two different people in the same room, with the same size TV, and both may well have a different opinion of the right size screen for that room and the best viewing distance.

However, it can help to get some solid numbers to give us a starting point, so let us consider how we might do this. There are two ways to approach the issue:

  • Decide on the screen size you want, and then calculate the ideal viewing distance
  • Estimate the viewing distance in your room, and calculate an ideal screen size for it

A good rule of thumb is that the ideal viewing distance for a flat screen HDTV is between 1.5 and 3 times the diagonal size of the screen - and we can use this to calculate both approaches.

Calculating the Best Viewing Distance from Your TV Screen Size

Firstly, if you already know the screen size for your room, then you can use this to calculate a good viewing distance.

For example, if you have a 40 inch screen, then your ideal viewing distance will be between 60 inches (1.5 x 40 inches) and 120 inches (3 x 40 inches) - or 5 to 10 feet.

The following table shows a range of common screen sizes and shows a suggested minimum and maximum viewing distance.

Flat Screen TV Sizes and Suggested Viewing Distance Table Flat Screen TV Sizes and Suggested Viewing Distance

Calculating the Best TV Screen Size from Your Viewing Distance

Alternatively, you can look at this from the other direction - starting with your viewing distance and working out a good screen size.

In many rooms, the viewing distance from the screen is pretty limited - there aren't usually too many options where you can put the TV and the seating. Therefore if you can estimate how far from the TV you will be sitting, then you can get a rough idea of the best screen size for that room.

This time you can divide your viewing distance by 3 to get the minimum screen size - and by 1.5 to get the maximum screen size.

So, for example, if you know the viewing distance in your room will be about 10 feet (or 120 inches), you can work out that a good TV size will be in the range of:

120 inches ÷ 3 = 40 inches minimum screen size

120 inches ÷ 1.5 = 80 inches maximum screen size

Now, that still gives us quite a bit of choice, but at least we can rule out screens below 40 inches and we've got a better idea of where to start looking.

TV Viewing Distance to Screen Size Table TV Viewing Distance to Screen Size

Also, remember these are only rough guidelines - so if you want to watch a 60-inch screen from 4 feet then go ahead - there's no law against it!

Some Other Things to Think About...

These guidelines give us a good starting point.

However, as I said earlier, this isn't an exact science and two different people will probably have two different opinions on what is a suitable screen size for a room.

So, now you have a rough idea of your screen size and viewing distance, there are a couple of extra points to consider to help you make your final decision.

1. Standard, High-Definition & 4K Pictures

If you will be mainly watching high-definition or 4K Ultra HD images, then a larger screen will allow you to appreciate the extra detail more - and also allow you to sit closer. So you will probably benefit more from a bigger screen or a shorter viewing distance. Or both!

On the other hand, if you are still watching a lot of standard-definition TV, then the reduced resolution may be more obvious on a larger screen - and you may see the imperfections more if you sit too close.

2. What Type of TV Will You Be Watching?

If you will be mainly watching movies and documentaries - or anything where you sit down for a long period and concentrate - then a larger screen is perfect for you to appreciate the action and detail. You may also enjoy being closer to the screen.

On the other hand, if much of your TV viewing is for shorter programs that require less attention - or your TV is on 'in the background' much of the time - then a bigger screen may be too overwhelming in the room and so a longer viewing distance/smaller screen size may be better.

3. Where Will the TV Be Installed?

A large TV installed on a wall can sometimes integrate into a room more easily than one standing on a piece of furniture.

The size of the wall, and the fact that the screen seems to be more 'removed' from the room, can often make a larger TV to appear slightly smaller and less obvious.

However, standing on a unit or TV cabinet, the television can appear to be more 'on top of you' and a larger size may appear too big.

4. In a Home - Not a Shop

Be careful if you go into a shop to get a feel for the size of a particular TV.

A large shop floor with many other TVs around can make it difficult to judge the size of a screen. If possible, try an see a similar-sized screen in someone's home where you will get a better perspective on the size.

Another trick you can try is to cut a piece of wood or cardboard to the same size as the TV you are thinking of getting. Place this in the approximate position in your room and you will get a good idea of how big the TV will look when you buy it.

5. If in Doubt...

In my experience, you will get used to a large screen very quickly. When you first install a large flat screen TV it may seem ridiculously big compared to what you may have been used to. However, you will very soon get used to the new size... and you may even start wishing you bought the next size up.

In my experience, if in doubt... go for the bigger one!


If you are wondering about the best viewing distance for your room, it can seem a difficult choice.

However, once you think about things logically, then it can become much clearer.

Get a feel for a good viewing distance by working it out from your screen size - and then take into account the way you will be using the TV and the type of things you will be watching.

There are similar arguments for choosing the right TV screen size for your room.

You can get a rough idea by working out the viewing distance you will have - and then you can calculate a broad range of suitable sizes.

After that you need to consider things like the type of images you will be watching on the TV, the way in which you will be using the screen and where in the room you will be installing it.

Oh, and don't forget the golden rule... if in doubt, get the bigger one!