Both 4K and HD are types of screen resolution. But there are significant differences between the two – and it’s all to do with the number of pixels that make up the screen and create the picture. 

HD and 4K TVs – the current state of play 

HD TVs were the standard choice in living rooms throughout the noughties and beyond. 4K Ultra HD arrived on the scene in 2013/14, but it’s only in recent years that 4K TVs have truly replaced the humble HD TV. Most new TVs you can buy today are 4K Ultra HD. 

What is TV resolution?

TV resolution refers simply to the number of pixels that are displayed on your TV screen to create the picture. A pixel is the smallest point of light that makes up the image on screen.

The greater the number of pixels a screen has, the clearer the image will become – and the higher resolution. Depending on the number of pixels, TVs can be referred to as:

  • Standard definition (SD)
  • High definition (HD)
  • Full HD
  • 4K
  • 8K

How is TV resolution measured?

Screen resolution is measured by counting the number of pixels horizontally and vertically (by width and height). Usually the number of vertical pixels is used to describe the resolution, alongside whether it is standard, high, full HD or 4K definition. 

For example, a 576p TV refers to standard definition (SD). The measurements here are 704 x 576 pixels, which is 405,504 pixels in total.

What is HD TV?

High definition TV refers to a television screen made up of at least 1,280 x 720 pixels (sometimes called 720p). This is over twice the number of pixels as an SD TV (921,600 pixels in total), which is the minimum resolution for a TV to be labelled HD. 

As there is a greater number of pixels displayed, most HD TVs have a screen that’s around a third wider than standard TVs. Enjoy better colours and clarity, and sharper, more lifelike images on screen. 

What is UHD television?

So what about UHD and what does ultra HD mean on a TV? We often get asked ‘is ultra HD better than HD’? And there are a few key differences to note. Firstly, ultra-high definition (UHD) is a further step up from HD TVs. They have a TV resolution of 3,840 x 2,160 pixels, which is double the number of vertical pixels of Full HD, and four times the number in total (8,294,400 pixels). 

This is the main UHD and Full HD difference and for this reason it’s sometimes known as 4K. The higher pixel density creates a clearer, more defined image that shows your favourite series, movies and sports in greater detail and depth.

Is ultra-high definition worth it?

A greater screen resolution with a UHD TV significantly improves your viewing experience, compared to HD TVs. Sharper lines, smoother curves and clearer colour contrasts enhance all types of content. 

  • Immerse yourself in movies as 4K resolution adds greater depth. 
  • See every kick in a football match and the sweat on players’ faces, bringing you closer to the game. 
  • Play your favourite games with 4K-enabled consoles and see your enemies appear sharper.

With improved pixel density, you can sit closer to the screen without losing clarity. The image remains clear even when you’re close up, without seeing the pixels. This is ideal where space in your living room is limited, or if you want and have room for a TV of more than 40 inches in size. 

What is 4K TV?

4K televisions have screens that use four times more pixels than a Full HD TV to display a picture. The term 4K is therefore often interchangeable with UHD and sometimes called 4K UHD – as they both have the same screen resolution of 3,840 x 2,160 pixels

Place the pixels of a Full HD display onto a 4K screen and it would only fill a quarter of it, for example. This shows the level of detail you get with 4K TVs compared to a HD model. 

There is also such a thing as Cinema 4K, which is 4,096 x 2,160 pixels. This was introduced in digital cinemas but is not yet available on home TVs. 

Do you need a 4K TV to watch 4K content?

Yes, and the way to get the best from any 4K TV is to watch 4K content. Netflix, Amazon Prime Video and Sky are all producing 4K content, from TV series and blockbuster movies to live sport.

4K TVs work with High Dynamic Range (HDR) too. While 4K increases the number of pixels, HDR-enabled content improves the quality of the overall image. This grows the colours from a palette of more than one billion – delivering deeper blacks and brighter whites for a greater contrast.

Can you tell the difference between 1080p and 4K?

Yes, especially if you change from a TV that has the same screen size. The most effective 4K televisions are 55 inches in size or above. By switching to 4K from HD you are instantly introducing four times as much detail to the screen. 

You can tell the difference by sitting closer to the screen too. This fills up your field of view to form a more immersive experience, as lines remain defined and colours stay bright and bold. The human eye can only perceive so much but the difference between 1080p and 4K is visible.

What do the experts say?

According to Which?, 4K TVs are better at displaying HD content than Full HD models, whether you want a 40 or 55-inch TV. The inclusion of new technologies such as HDR is another reason to invest according to Tech Radar, along with the extra nuance and detail delivered on screen compared to HD TVs.

Explore the range of TVs at LG and find a 4K TV for your living room today. Find your perfect TV