4K resolution: what it is and why it matters for your TV

We take a look at 4K resolution, what it means, and why you need a 4K TV

Features By Max Slater-Robins published 12 October 2024

Anyone who has bought a TV, or even thought about buying a TV, in the past few years will almost certainly have come across the term 4K resolution, which is one of the major selling points of the best TVs on the market. 

Sometimes referred to as Ultra HD, or UHD, 4K started life in around 2005 with a new standard from the Digital Cinema Initiatives organisation but didn't catch on until some years later, in the mid-2010s, due to the expensive nature of the components needed to make a 4K TV or monitor. 

For TVs, the generally accepted resolution of 4K is 3840 x 2160 pixels, or exactly four times the pixel count of 1080p, or Full HD. This increased pixel density offers sharper images, more detail, and better clarity, especially as TVs and monitors have grown larger. 

4K adheres to a 16:9 aspect ratio, ideal for TVs, monitors, and projectors.

In some cases, 4K Ultra HD is known as 2160p resolution, a naming convention that derives from HDTV and SDTV formats, and uses the number of pixels along the vertical axis, not the horizontal axis. Today, we're focusing on the CEA Ultra HD standard used for consumer 4K TVs. 

What exactly 4K is called isn't hugely important – the upshot is that 4K TVs and 4K monitors offer a much larger number of pixels (both in absolute and per inch terms) than 1080p or 720p HD displays. Both from close up and from distance, 4K just looks better than its predecessors and has now become the standard for TVs. 

How 4K differs from HD and 8K resolutions

The transition from HD (1080p) to 4K marked a dramatic improvement in picture quality. Full HD, or a resolution of 1920 x 1080 pixels, contains roughly two million pixels, while 4K has over eight million pixels. 

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