Televisions

What is 4K TV?

By Andrew Laughlin

4K TV is the next evolution of TV picture quality, displaying four times the detail of current high-definition. We help you decide whether a 4K TV is right for you.

Put us to the test

Our Test Labs compare features and prices on a range of products. Try Which? to unlock our reviews. You'll instantly be able to compare our test scores, so you can make sure you don't get stuck with a Don't Buy.

Whether it's HD or 4K, find the best television for you with our expert and independent TV reviews

What's so special about 4K TV?

You'll see the names 4K, Ultra HD, UHD and even 4K Ultra HD being banded about - but they all refer to the same thing. This is a TV with a resolution of 3,840 x 2,160 pixels, more than 8 million pixels in total, which is four times the number in Full HD (1,920 x 1,080).

Watching 4K TV at its best, you'll see everything on screen in crystal-clear clarity and sumptuous detail. There's so much detail and depth in the picture that it almost feels 3D at times - and you won't need special glasses to watch it.

All the big brands, including Samsung, Panasonic, LG and Sony, now offer large ranges of 4K TVs - from entry-level models priced under £1,000 to monster sets costing many thousands of pounds.

You'll generally find that 4K TVs are big screen models of 40-inches or over. This is because to really appreciate the higher picture quality you need to watch it on a large TV, as it's rather lost on a small screen.

Best 4K TVs

Samsung UE55KS8000
Today's best price £1,448.98
Which? score 78%
Tested Jun 2016
Best Buy
Picture quality:
4 out of 5
Sound quality:
5 out of 5
Ease of use:
4 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

It matches some of the best sound we’ve heard from a TV, with a pin-sharp picture and nicely balanced colours, comfortably surpassing the Best Buy cut-off. With both premium features and performance, this is a TV worth blowing the budget on.

Samsung UE55KS9000
Today's best price £1,598.89
Which? score 77%
Tested Jun 2016
Best Buy
Picture quality:
4 out of 5
Sound quality:
5 out of 5
Ease of use:
4 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

Another set with a sizeable price tag, this TV may leave your pockets feeling a little lighter but you won’t regret it. With all the features you could wish for, supreme sound and very good picture quality, it’s a sure-fire Best Buy

Samsung UE49KS7000
Today's best price £798.99
Which? score 76%
Tested Jun 2016
Best Buy
Picture quality:
4 out of 5
Sound quality:
5 out of 5
Ease of use:
4 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

A touch cheaper than many other Best Buys, this set proves you don’t have to spend over a grand to get a top quality set. With vivid, balanced colours – particularly with 4K – there’s no scrimping on performance, either.

Samsung UE49KU6400
Today's best price £548.90
Which? score 75%
Tested Jul 2016
Best Buy
Picture quality:
4 out of 5
Sound quality:
5 out of 5
Ease of use:
4 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

Matching the score of TVs more than double its price, this bargain Best Buy’s natural, balanced colours are a joy. You still get 4K HDR – a feature typically found on higher-end sets. This is affordability without compromise.

Samsung UE43KS7500
Today's best price £748.99
Which? score 75%
Tested Jul 2016
Best Buy
Picture quality:
4 out of 5
Sound quality:
4 out of 5
Ease of use:
4 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

Some may see curved TVs as a bit of a gimmick but this one will impress nonetheless. Combining a great picture with decent sound and an easy-to-use interface, this set is a comfortable Best Buy.

The 4K future is coming...albeit slowly

Best Buy 4K TVs are outstanding and you’ll be getting a great TV if you buy one. However, do bear in mind that just as with high definition in its early days, we are a way off settling down to our evening's viewing in 4K quality.

We believe that 4K is the future of television viewing. It makes everything you watch look sharper and more detailed, and you won't need to change the way you already enjoy television as with 3D. However, there are big challenges ahead in getting 4K into your home:

  • 4K TV channels: Some 4K TV channels are becoming available to watch, such as BT Sport Ultra HD, but there aren't many. Big technical challenges remain in introducing 4K channels onto UK subscription-free platform, Freeview, and we feel that will be a big factor in this technology going mainstream.
  • Blu-ray: 4K Blu-ray discs should be with us by Christmas 2015, accompanied by the first 4K Blu-ray players. However, we don't know yet what extra quality 4K Blu-rays will bring over standard Blu-rays, and they're expected to cost more to buy.
  • 4K internet video streaming: Content providers have already begun streaming content in 4K (such as Breaking Bad and House of Cards on Netflix) but you'll need at least 15Mpbs broadband (ideally 20Mbps or higher) to get the best possible experience and not all 4K TVs can support it. We'll be running more tests of 4K video streaming over the coming months to see how things develop.

Some Blu-ray players can 'upscale' your normal Blu-ray discs to near 4K ultra HD picture quality. Discover more and browse fully tested models with our 4K Blu-ray players guide

4K TVs: Should you buy one?

With 4K TV prices falling and some great Best Buy TVs on the market already, this technology is definitely worth considering when you next upgrade your television. Just bear in mind that it may take a while for you to really enjoy the extra picture quality you're paying for.

Currently, high-definition TV is not broadcast on Sky, Freeview or Virgin Media in Full HD 1080p, instead going out of at the reduced format, 1080i (for more on that, see What is HD TV?). Therefore, we will need a big leap forward in terms of technology to get higher quality 4K TV pictures into your living room.

New technology is emerging that can compress the huge amount of data involved in 4K into forms that can be more easily distributed not just on television, but also on Blu-ray discs and over the internet.

Although it took HD TV over a decade to become a mainstream after the first HD TVs launched in 1998, we don't think it will take so long for 4K ultra HD. You certainly won't be wasting your money by going for a Best Buy 4K TV, but just bear in mind the limitations in terms of 4K content to watch.

How we test 4K TVs

To test 4K TVs, we use two clips at 3840×2160 resolution (shot by us using professional 4K cameras) and play them on the TVs using a specialist set-up. Each scene is designed to push the 4K TVs to their limits.

The TVs also go through all our usual standard and high-definition viewing tests, along with sound, ease of use and features. This gives you an overall test score that you can rely on.

To find the right 4K television for you, head to our television reviews.

Related products

See all televisions