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TV screen technology explained

What is 4K TV?

By Ben Stockton

Article 2 of 5

With four times the detail of high-definition telly, 4K Ultra HD is starting to become more widely available. But is it worth buying a 4K TV?

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You'll see the names 4K, Ultra HD, UHD and even 4K Ultra HD being bandied 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 8m pixels in total, which is four times the number in Full HD (1,920 x 1,080).

What's so special about 4K TV?

Watching 4K TV at its best, you'll see everything on screen in crystal-clear clarity and sumptuous detail. There's a level of detail and depth that HD sets simply cannot achieve – at times, it almost feels 3D.

All the big brands, including Samsung, Panasonic, LG and Sony, now have large ranges of 4K TVs, from entry-level models priced around £500 to monster sets costing many thousands of pounds.

You'll generally find that 4K TVs are big-screen models of 40 inches or more. 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 Buy 4K TVs

The best 4K TVs will put those extra pixels to good use, matching the pin-sharp detail with beautifully balanced colours and vivid contrast. But while a good TV will have great 4K picture quality, a Best Buy TV matches this with superb sound and easy-to-use smart TV features.

Below, we’ve included a selection of 4K sets at different prices to show you needn’t break the bank in the search for 4K quality.

Only logged-in Which? members can view our recommendations in the table below. If you’re not yet a member, you can get instant access by taking a £1 trial with Which?.

Best 4K TVs

Samsung UE55KS8000
Today's best price £1,129.00
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 £1,195.00
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 £699.00
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 £538.06
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 £690.00
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.

Not found the product for you? Browse all of our TV reviews

Where can I find 4K content?

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

There are some big challenges ahead before 4K is a staple of most households’ TV watching. But content is becoming more widely available, be it through broadcast TV, ultra-HD Blu-rays and internet streaming:

  • 4K TV channels Some 4K TV channels are becoming available to watch on pay-TV services, such as BT and Sky, but there aren't many. Big technical challenges remain in introducing 4K channels on to subscription-free service Freeview, and we feel this will be a big factor in this technology going mainstream.
  • Blu-ray More and more 4K ultra-HD Blu-rays arrive on shelves every month, but you’ll pay a premium, not only for the discs but for the players as well. 4K Blu-ray players start at around £180 – check out our reviews to find the best one for you
  • 4K internet video streaming Content providers such as Netflix, Amazon Video and YouTube have already begun streaming content in 4K. But you'll need at least 15Mpbs broadband (ideally 20Mbps or higher) to get the best possible experience. Before more 4K channels become available, internet streaming will likely be your biggest source of 4K content.

Don’t Buy 4K TVs

4K is no assurance of quality – there are plenty of poor 4K TVs out there. Picture quality comes down to more than resolution alone, so simply looking for 4K certainly doesn’t guarantee you a great TV. 4K TVs can still fall foul when it comes to picture quality, including contrast and colour balance, as well as other factors including sound and ease of use.

We’ve seen a number of shoddy 4K sets in our lab, with some so bad we’ve made them Don’t Buys.

The table below rounds up some of the worst 4K TVs from our testing. Despite their 4K resolution, these TVs can have gaudy, unbalanced colours or poor contrast that looks washed out and drab.

4K TVs to avoid

Philips 49PUS6401/12
Typical price £699.00
Which? score 48%
Tested May 2016
Picture quality:
3 out of 5
Sound quality:
2 out of 5
Ease of use:
3 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

Unnatural colour balance from this 4K TV give actors perma-tan skin tones, while the poor contrast means you’ll miss detail in both the darker and lighter areas of the picture.

Panasonic TX-40CX400B
Today's best price £399.99
Which? score 44%
Tested Oct 2015
Don't buy
Picture quality:
3 out of 5
Sound quality:
1 out of 5
Ease of use:
3 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

Despite having 4K resolution and coming from a top brand, this Don’t Buy TV failed to impress in the Which? test lab. The 4K picture is sharp but blurry  on everyday HD TV. It sounds utterly awful, too.

Hisense H55M7000
Today's best price £599.00
Which? score 43%
Tested Oct 2016
Don't buy
Picture quality:
3 out of 5
Sound quality:
1 out of 5
Ease of use:
3 out of 5
Screen size:
Member exclusive
Curved:
Member exclusive
HDR:
Member exclusive

A similar price to some of the Best Buys above, this 55-inch 4K TV can’t stand up to the best-quality sets out there. Colours are too warm and unnatural, and the sound lacks richness.

Should I buy a 4K TV?

Many of today’s Best Buy TVs are 4K. This is because most new TVs from the big manufacturers are now 4K, with Full HD typically being available only on their cheaper sets. Plus, 4K TV prices continue to drop. So if you’re looking for a new TV, we’d recommend buying one with 4K.

But with HD still forming the bulk of content available to watch, if you’ve got an HD TV that you’re happy with, you shouldn’t feel the need to rush into replacing it with a 4K set.

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

Although it took HD TV more than 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.