The old adage 'bigger is better' is often applied to TVs. And many big screens are now more affordable than ever, especially during sales periods, so you can live out your home cinema fantasies without breaking the bank.

But it is possible to buy a TV that's too big. Sounds crazy, but it's true. An oversized screen is uncomfortable to watch and you'll get sick of it pretty quickly.

You can avoid this, or a TV that's too small, by figuring out the right TV size for your room. Measuring everything up is a quick and easy process that will improve your viewing experience and quite possibly save you from wasting money buying a bigger screen than you need.

Note, this guide covers optimal viewing distance. Setting up sound is another subject entirely.

On this page:

• How to choose the best TV size for your room
• What's the best TV size for a bedroom?
• How to figure out viewing distance with a calculator
• Factoring in field of view
• How high should my TV be?
• How to measure a TV
• What's the best TV?

What you'll need

Get your hands on a sizable tape measure (10m or so) and a friend to hold the other end while you walk across the room. Bribe them with the promise of movie nights on your sweet new setup.

TV screens are still measured in inches, one of the few imperial holdovers in an otherwise metric society. Be prepared to make some conversions.

Finally, everyone's eyesight is different.If you live with a degree of vision impairment, or if something just doesn't look quite right, follow these steps and then trust your eyes to guide you the rest of the way.

How to choose the best TV size for your room

Setting your room up with the optimal viewing distance will get you many steps closer to the best picture quality and level of immersion. It can also help reduce issues like eye and neck strain.

You need to sit a certain distance from the TV to enjoy these benefits. The size of your room is one of the biggest factors as this will determine where your furniture and TV should be placed.

But the most important measurement is the distance between your seated viewing position and the TV screen. This will be smaller than the full length of the room.

Let's say your lounge room is five metres long and you plan to put the couch at one end and the TV at the other, with each against, or close to, a wall. That means you want to find a TV best viewed at five metres, right? Not exactly.

Measure the distance between your eyes and the screen, not wall to wall.

Your face isn't actually flat against the wall like the back of the couch. The distance between the wall and your eyes is probably around 30–50cm. TVs on a stand or entertainment unit are the same. They also sit away from the wall, possibly around 50cm as well. So in this case, the actual viewing distance between your eyes and the screen is four metres.

The easiest way to measure this is to ask your friend to stand where the TV will be, then draw the tape measure to your planned seating position. Remember, you're probably going to be leaning back on the couch, so don't measure from a bolt upright position. Then, you can pick the correct TV based on the measured viewing distance.

CHOICE tip: This isn't an exact science, so you don't need to worry about precise positioning. Your viewing experience will still be great as long as you're in the right ballpark.

What if I wall-mount the TV?

If the TV is more or less flush against the wall, e.g. five to ten centimetres out, then you don't really need to factor it in when calculating viewing distance. It is worth noting if the gap is greater than 10cms.

Should I still measure the room?

Absolutely! You still need to make sure the TV, furniture and other peripherals can physically fit in the space. TV units, floor standing speakers, shelving and so on can take up and lot of room and you don't want them overcrowding the TV.

Choosing the right size and resolution

Once you've figured out the viewing distance, you can choose from a few different TV sizes which fall into a suitable range. Resolution also comes into play here.

Broadly speaking, sitting too close can cause eye and neck strain while sitting too far back can make it difficult to focus on the content. This is the result of the relatively smaller screen size and distractions in your peripheral vision.

However, if you're a fan of 4K ultra-high definition content (UHD), you need to ignore all the warnings you were given as a child and sit closer. This is because the extra detail is only viewable from a certain distance and if you sit too far, the pixels will become harder to distinguish and ultimately look no better than HD.

The ideal 4K viewing distances for the three most popular TV sizes are below.

But not everyone is overly fussed about the whole 4K thing and that's ok. You may have wound up with a 4K TV simply because there are barely any HD models around these days. In this case, while the viewing distances are similar, you only need to consider the optimal distance for HD.

While most 4K TVs have good upscaling technology (which makes SD and HD footage look 4K), you will notice imperfections in SD and HD if you sit too close. If you own a 4K TV, but mainly watch SD and HD content, follow the HD viewing distance chart.

The ideal HD viewing distances for the three most popular TV sizes are below.

CHOICE tip: Upscaled SD footage can only look so good on a modern, 4K TV. Sit within the HD viewing range when watching SD content for the best results.

What's the best TV size for a bedroom?

Bigger is often better – except in the bedroom. Unlike an entertainment area, where the TV is likely to be the central focus, it's better to swing towards a smaller screen for your sleeping space. A 42 or 55-inch screen should be suitable

How to figure out viewing distance with a calculator

While the tables above should help you find your ideal screen size pretty easily, you can always let a machine do the maths for you. The great folks at Good Calculators have put together a free website that calculates (among other things), ideal viewing distance.

The results are based on measurements used by the The Society of Motion Picture and Television Engineers (SMPTE) and THX (the company that makes that bwarrrr sound before movies). CHOICE has used SMPTE research to inform various aspects of our TV test. We recommend going with its suggested viewing distance over THX.

This calculator is handy if you want to find out whether your dream TV will fit the viewing distance of your room

All you need to do is enter the TV resolution and diagonal screen size. The calculator will output the SMPTE's and THX's recommended viewing distances.

This calculator is handy if you want to find out whether your dream TV will fit the viewing distance of your room. However, it's still worth measuring the viewing distance and room dimensions yourself, just to make sure.

CHOICE tip: The calculator can compensate for visual acuity. If you don't have 20/20 vision, select a different option from the 'Eyesight of Viewer' dropdown menu.

Factoring in field of view

If you really want to get into unabashed technical nerdery (and we recommend that you do because this sort of thing is fun), then you should also calculate the field of view (FOV) relative to the viewing distance. A correct FOV will increase immersion which can really improve your viewing experience.

The optimal FOV is largely determined by the content you're watching. For example, when you're watching a movie you can sit a little closer as your eyes are typically locked to the centre of the screen while other stuff happens around the edges. But when you're watching a sports match, you may follow particular players around the screen and this can quickly wear out your eyes at a shorter distance.

You probably don't want to move your lounge around every time you watch a different type of content, so the best all-rounder field of view is 30 degrees

Of course, you probably don't want to move your lounge around every time you watch a different type of content, so the best all-rounder FOV is 30 degrees. This catch-all position covers enough of your peripheral vision to immerse you without risking eye strain or nausea. 

As you move further back from the TV, your field of vision relative to the TV will narrow. This can actually make the screen look smaller as your peripheral vision (at around 30 degrees) will be distracted by all the space, furniture, plants and more around the television.

If you sit further back, your field of view will insclude things around the TV, which can be distracting.

To calculate FOV, sit directly in front of the TV at your chosen viewing distance and then either:

1. Bust out the protractor and keep moving the seat/couch back and forward until you're exactly at 30 degrees.
2. Reject maths, trust your eyes and adjust your seat until your peripheral vision is close to the edges of the TV.

Unless you're a perfectionist, an approximate FOV should be fine. Just consider the content you mainly watch (sports, news, movies etc) and don't sit too far back.

Choice tip: Movie buffs chasing a more cinematic experience can sit a bit closer. Aim for a 40-degree FOV.

How high should my TV be?

The screen needs to be at eye level from your seated viewing position. That way you can comfortably watch without having to move your head around.

But TVs can be quite big and there are two schools of thought as to which part of the screen you should focus on. Some say the middle third of the screen, others say the bottom third. 

Which one's better? Jury's out, but at CHOICE, our viewing panellists look towards the middle third of the screen during our tests.

Just don't mount your TV too high, because you want to avoid looking up to any significant degree. This can cause eye or neck strain after a while. 

Angling it forward doesn't really compensate for this very well and it affects your field of view. 

Finding the right height

To start, sit in your ideal viewing position and measure the distance from the floor to eye level. Record the distance, this is the height to position the TV on the wall mount.

Next, decide whether you want your line of sight to focus on the middle or lower third of the TV. Then position the TV so the centre of the viewing area lines up with your viewing height.

Adjust your viewing position to focus on the middle or lower third of your TV.

Like field of view, this doesn't have to be exact. Most TV cabinets, stands or entertainment units are around the right height and wall mounts are beholden to studs. As long as your TV is positioned in the general area, it's going to look fine.

CHOICE tip: Don't put your TV on a table, chest of drawers, desk etc. These are typically too tall for comfortable viewing.

How to measure a TV

Now that you've figured out the best TV size for the room, it's time to make sure it fits. All you need to check is the height, width and depth of the screen and the stand if you don't want to wall mount.

You probably don't need to worry about measuring the thickness for wall mounting, as most modern TVs should fit in the bracket. The specifications will also note all dimensions if you need to check before buying.

These can vary quite significantly across different brands and models, even if the screen size is the same. Don't assume that a 65-inch Samsung TV will be the same size as a 65-inch LG, for example.

CHOICE tip: You don't need to measure the diagonal screen size. Its unnecessary and you may end up scratching the screen.

Remember to measure the TV's feet or stand if you're going to put it on an entertainment unit.

What's the best TV?

By now you have all the info you need to select and set up the right TV size for your room.

But that's only half the battle. You'll also want to choose a model with good picture and sound quality, that's easy to use, energy efficient and has a good range of features. That's where our expert reviews come in. Our results can show you the best models for your budget and stop you from wasting your hard on cash on a dud model.

Head to our TV test results now to find the kind of TV that will make all your friends envious on movie nights.

Stock images: Getty, unless otherwise stated.

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