HDTV Size and Distance Calculations

How big should my HDTV be? How far should I be sitting from it? One or both of these questions are usually the toughest thing consumers are faced with when preparing to buy an HDTV. The simple answer to the first question is, as big as you want and your budget will allow. The answer to the second question is as close as you can stand it. HDTV was designed to provide the viewer with a sharper more life-like picture, and it was also designed to occupy a greater portion of your field of view. Consumers are free to choose whatever size they want, and view the HDTV from any distance they choose; but if you really want to experience HDTV as intended, the size you choose and the distance you view it from matters!

Most consumers have a difficult time getting their head around how large their new HDTV must be or conversely how close they must sit to it. For those who are unfamiliar with the topic, you may want to read this basic article on sizing your HDTV. Much of the confusion surrounding HDTV sizing/viewing distance has to do with the fact that television is not new, and even though TV technology is evolving, we still want to apply the old rules to that new technology. Adding to the confusion is that there is no one single standard that everyone agrees on. There is not even complete agreement on one of the things that most of the standards factor into their recommendations, visual acuity (the limitations of human eye sight).

Back in the good old days (did I just date myself there?), the size of the TV and the viewing distance was pretty much a personal choice. The resolution that televisions were capable of producing didn’t make the limitations of human eye sight a factor. Based on the most commonly held theories on human visual acuity, if you possessed 20/20 vision you could view standard cable TV broadcasts on a 27” TV from as far back as 14 feet without missing the minutest detail. In a standard 12 x 16 foot family room, by the time you account for the 2 foot depth of the set, another 6 inches or so of clearance between the TV and the wall, and another foot for the combined depth of the back of the couch and your head, you could place the set anywhere in the room without diminishing the picture quality. Now mind you, the interlaced scanning used with analog television makes even still images a little blurry, but when you combine this with the limited resolution and add movement in the images, you could effectively watch television from an even greater distance without any reduction in your viewing experience.

HD television is a quantum leap forward from what most consumers have experienced with television. Even for consumers who own extended definition tubes or rear projection big screens capable of displaying all the resolution that digital cable could offer, HDTV is a big step. The transition to HDTV with regards to the set size/viewing distance would be easier for consumers to accept if HDTV was introduced only at a 720p resolution and had stayed at that resolution for 20 years or so before 1080p was introduced.

To get your head around the radical change in set size/viewing distance you have to understand two things; pixel count and the limitation of the human eye to resolve detail. The effective pixel count of a very good analog TV is 204,800 (512 x 400) pixels. Standard definition digital TV (SDTV), whether displayed in the 4:3 format like analog TV or the 16:9 format has a count of 355,200 (704 x 480) pixels. If an analog TV and digital TV sets are the same size and dimensions, the increased pixel count of digital TV means that each pixel has to be smaller than on the analog TV. The good news is the smaller pixels make the image you see crisper and more realistic. The bad news is smaller objects are tougher to see from a distance, which brings our ability to see and resolve detail into the picture.

The ability to resolve the details of objects (generally referred to as visual acuity), has been studied by scientists for over 100 years. The measurements of our ability to see fine detail is defined in degrees, just like a circle. Defining our ability to see in that manor removes the issue of how far away we are from the object we are trying to make out.

object size to visual acuity angle as distance increases

If you think of an open ended triangle that stretched out to infinity and a vertical line of fixed length that crossed the two sides of the triangle. As you move the point where the two side of the triangle meet away from the vertical line, eventually the vertical line will no longer cross the two sides of the triangle. With regards to our ability to see detail, once an object can no longer touch the two lines of the triangle, we can’t make out the detail. The most widely accepted belief is that a person with “normal” vision can resolve detail down to as small as 1/60 of 1° of a circle; some believe that we can resolve detail a little smaller than 1/120 of 1° of a circle. Whatever the limit is, the important thing to remember is if it is too small we can’t see it.

The more pixels that make up a picture, the sharper the image will appear. So to provide us with a better picture, HDTV increases the count of pixels used in the display. With our ability to see detail fixed, we have to move closer to the image or make the image bigger once we pass the threshold of our visual acuity to see all the detail. With 1080p HD resolution being the choice of consumers buying televisions today, the 2,073,600 (1920 x1080) pixels that makes up its display, is 10 times the count of the pixels of analog TV. So we are not taking about a little change but a major overhaul of the size of our TV and/or the viewing distance. That is why the recommendations for HDTV size and the distance you should sit from them seem so outlandish, a lot has changed. For the interior designer (real or a voice inside your head), who is telling you, “you don’t want a TV that big in the room because it will dominate the room”, SHHHHH!; or you can listen to that voice and diminish your television viewing experience.

There are many recommendations to be found on the topic of TV size and viewing distance, the most commonly quoted are the SMPTE and THX recommendations, and the manufacturer / retail recommendation (diagonal measurement of the screen size times 2.5 to get your seating distance) . Less quoted recommendations are those based purely on visual acuity or the design goals of HDTV. If you want to figure out the size and/or viewing distance from your HDTV, we have created an HDTV size/viewing distance calculator which is located at the bottom of this page. Although there are many viewing distance calculators already available on the web (some better than others), we have re-invented the wheel so to speak, to address their short comings. Some of the calculators are difficult to use even if you have knowledge of the topic, and the better ones are geared towards the construction of a home theater with multi-row seating. Since most buyers of HDTVs are not constructing a multi-row home theater, some of their recommendations are inappropriate where HDTV is concerned. In addition to the raw data, we also present relevant background information with regard to the theories behind the numbers.

HDTV Size - View Distance Calculator

Your answers to the questions (that follow) will be used to estimate your optimal HDTV size/viewing distance. But first, here are some navigation tips.

  • Click “Next” to advance to the next question.
  • Click “Go Back” to go back to the previous screen.
  • Click “Finish” to generate the HDTV size/distance calculations.

The data presentation page has background information to help you make an informed decision. Much of the background information is hidden from view if you are using a modern browser with java scripting enabled (to keep the page from being cluttered). To reveal the background information, simply click on a heading.

Your Goal

What is your goal?


I would like to have an HDTV with the highest resolution, and I would like the best viewing experience possible.
I would like to have the best resolution possible.
I just want a new HDTV.

Size / Distance


I know the distance from the primary seating location to the TV.  
I know the display size I would like to have.  



My HDTV will be placed on a stand.
My HDTV will be wall mounted.

Your Solutions

Based on your responses, which were: