What size TV do I need? How to work out the best screen size for your home

Big-screen TVs are a wonderful thing, but if you're not sure what the right size for you is, then you’ve come to the right place...

It’s easy to be dazzled by big screens in the showroom, but things can look very different when your dream display is unpacked in your living room.

Essentially TV showrooms are a terrible place to pick a TV, with bright lights, high ceilings and the screen backlights and contrast wound up to the max, surrounded by other giant TVs. But if you measure up in advance and ask the right questions you can buy a display that will give you a great experience from the sofa, the bed or even your bath. And remember, you’ll probably be watching this TV for the next eight years, so choose wisely. 

[Read more: Six easy ways to watch 4K TV]

How big is too big?

Some people say you can never go too big, but if your TV isn’t comfortable to watch or it feels like you’re always living in its shadow, it’s probably too big.

Calculations for choosing the best distance to sit from your TV are usually based on one adult, with good eyesight, sitting directly in front of the screen. That might work for a dedicated home cinema, but the real world doesn’t usually look like that.

For example, children have very flexible eyes that focus easily very close to a screen, and they’re often happier that way. Your eyes get less flexible as you age and the distance for comfortable viewing increases as you get older too.

Why is viewing distance important?

Despite what your mum and dad said, sitting too close to the TV won’t give you square eyes, but it might give you eye strain if you have to move your head around to follow what’s on screen. This is the Field of View, and it’s about 15° either side of your nose.

You also want to avoid being so close that you can see the pixels on the screen - the tiny dots that make up the picture. A 4K Ultra HD screen has about four times as many pixels as a Full HD screen, so you can sit a lot closer before you can see the pixels, or have a much bigger screen.

What size TV do I need?

The simple viewing distance rules for HD and 4K

The guide above (produced by Samsung) shows the range of viewing distances for TV sizes from 20in to 100in with standard definition, HD, Full HD and 4K Ultra HD screens. Don't forget: TVs are measured diagonally across the screen (ignoring the bezel around it).

The advice from different screen manufacturers varies slightly, with some suggesting you should sit at a distance three times the vertical height of your screen, and others that you should divide the viewing distance by three to find a diagonal size for your screen. They're all trying to find an easy way to explain the science of how our eyes work. 

We're trying to find the best TV for your room - assuming you're not buying a new house to fit your dream TV. An easy rule to find the best screen size for a Full HD TV is to halve the distance from your seat to your screen. For 4K Ultra HD TVs, it’s about two-thirds of the distance from seat to screen.

If you sit 1.5m (4.5ft) from your screen, you should have the best experience with a Full HD screen of about 32in, and a 4K Ultra HD screen of around 42in.

The average UK viewing distance is 2.5m (8ft). This gives you a 50in Full HD screen and allows you a 65in 4K Ultra HD screen.

If you’re more than 3m from the screen, then you can really indulge in a monster screen: over 60in for Full HD or more than 80in for Ultra HD. Maybe even think about a projector?

[Read more: TV screen tech terms explained]

BT Sport Chelsea v Arsenal in 4K Ultra HD

Who’s watching the TV?

If you’re watching TV with your family or friends, then the sweet spot is a matter of who gets to the best seat first. There could be two or three of you on the sofa and someone else in an armchair or second settee. Children have more flexible eyes and often prefer to sit closer to the screen.

This means you want a screen where the picture looks good for people sat either side of the screen - walk around it in the shop if you can - and you might need to be further away to expand the sweet spot.

What are you watching?

Light entertainment is a lot less demanding on the viewer than sport, drama, films or video games.

Talent shows and reality TV are brightly lit and shot in the centre of the screen, often with large talking heads. You can get away with a smaller screen or longer viewing distance because there’s less to watch.

Live sports, films and games often use the whole screen and have more detail, so you need a bigger screen to see everything. That’s even truer for video games, which often have text and small details that are crucial to the experience.

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