What Is 4K (Ultra HD)?

High definition has meant 1080p (1,920 by 1,080) resolution for years now, and it's ready for an upgrade. That's where ultra high-definition, or UHD, television comes in. You might have heard it called 4K. It's technically UHD according to the Consumer Electronics Association, but the two terms have become interchangeable. And now those terms finally matter a lot to your HDTV buying decisions, since 4K is finally a mature, accessible technology.
 
What Is 4K?A UHD or 4K display is one with at least 8 million active pixels. For televisions, that resolution has standardized to 3,840 by 2,160. Digital cinema 4K (the resolution in 4K movie theaters) is slightly higher at 4,096 by 2,160. However you define it, it's four times the number of pixels on a 1080p display, and over 23 times the resolution of standard definition television.

How Is 4K Different Than 1080p?For starters, 4K is obviously much sharper than 1080p. In the space that a 1080p HDTV holds a pixel, a 4K HDTV of the same size can hold four. That makes for a significant jump in clarity, assuming you have native 4K source material to watch in that resolution.

Because the resolution is much higher, it requires more bandwidth to transmit. The HDMI 2.0 standard was developed to support 4K, and allows 2160p video to be displayed at 60 frames per second. Older HDMI standards could work with a 4K source to some extent, but not reliably or at that framerate. You can also stream 4K video over the Internet, which similarly requires a very fast connection; Netflix recommends a steady 25Mbps downstream speed to watch 4K content over its service.

If you don't have a 4K source video, a 4K HDTV can still make your movies and shows look better. All 4K televisions use some kind of upconverter to display 1080p and lower resolution video. These upconverters do more than just break each pixel into four identical pixels; they employ edge smoothing and noise reduction algorithms to produce, ideally, a sharper picture. When it works well, you get video that looks natural on a 4K screen (though it doesn't add any actual new details, just sharper lines and more even color and light). When it doesn't, the picture can look a bit blotchy, like a painting.

While some regular viewers struggle to see the difference between 1080p and 720p in smaller television sizes, it's much more obvious on 50-inch and larger TVs. 4K is another significant jump in terms of clarity and detail, especially as people are becoming more and more used to the incredibly tiny pixels displayed by today's Retina-style HD screens on mobile gadgets. This is a major factor for large HDTVs as well, since 55 inches has become a low boundary for just how big a big screen can get.

What 4K HDTVs Are Out There Now?4K HDTVs have been hitting the market for a few years now, and have finally become both affordable and functional. 4K no longer has the pricing premium of early adoption, and you can get a good-performing 4K HDTV for about the same price as a mid-to-high-end 1080p HDTV last year.

Vizio's M65-C1 $1,754.99 at Amazon stands out as an Editors' Choice with surprisingly good picture quality and a big 65-inch screen for a reasonable price. If you want to go smaller, Sharp's 50-inch LC-50UB30U$697.99 at Dell can be found for even less. You can still go all-out if you want a flagship HDTV and are willing to spend big bucks; LG's 65EF9500 $4,999.99 at Dell 4K OLED television and Samsung's UN65JU7500FXZA $2,134.35 at WalMart deliver fantastic image quality, but both cost a pretty penny.
The availability of such a broad range of 4K HDTVs indicates that the market has matured past the point of early adopters and technophiles, to suit a wide range of buyers looking for the best new tech.

Is There Even Any 4K Content You Can Watch on an HDTV?
Thanks to Amazon and Netflix, there's a surprising amount of 4K content you can watch if you have a fast-enough Internet connection. 4K has gone past the eye candy landscapes and tech demo phase that early HD content went through, and now you can find plenty of television and movies in the format, like Breaking Bad, Daredevil, and Jessica Jones. Both services are steadily adding more 4K content, and if that isn't enough, YouTube supports 4K video for anyone from studios to GoPro users.

Blu-ray will bring you 4K in the future, as well. The Ultra HD Blu-ray standard lets studios release movies in 4K on Blu-ray discs, though they're more advanced Blu-ray discs than the 1080p-capable ones you're used to. You'll need a UHD Blu-ray-compatible player, and you'll have to buy new Blu-rays in that format when they start coming out next year, but they'll offer another way to get commercial 4K video easily.

Bottom Line: Do You Need 4K?You probably don't need 4K quite yet, but now is a good time to consider upgrading to a 4K HDTV anyway. The technology has become standardized enough that you can be reasonably sure a 4K television you purchase now will be ready for the future (just make sure it has HDMI 2.0 ports), and it's affordable enough to be compared directly with 1080p televisions in price.