4K, 8K, 1080p, HD and UHD. If you're shopping for a new TV, you've likely noticed these letter-number combos listed beside the word "resolution." But what's the difference between these resolution types? Is it worth paying more for an 8K TV versus a 4K TV? Does resolution even matter that much? Resolution may not be the most important factor when buying a new TV, but it's still something you should consider. Although it can get confusing, knowing what all the numbers really mean can help you feel more confident in your choice of TV. 

Here's what you need to know about resolution when it comes to TVs. The short version:

• 4K almost always means the TV has 3,840x2,160 pixels.
• UHD stands for "Ultra High Definition," also known as UltraHD, but basically means 4K.
• Are most TVs 4K these days? At 50 inches and above, yes. 
• Does 4K mean the picture will be better than my old TV? Not necessarily.
• If 4K is four times greater than 1080p, does that mean 4K is 4320p? No.
• Is 8K worth worrying about? No.

Still have questions? Let's start with the basics.

What is TV resolution?

Resolution, in terms of TV hardware, refers to the number of pixels that compose the picture on the TV. A single pixel, or discrete picture element, consists of a tiny dot on the screen. 

There are numerous resolutions found on flat-panel TVs. Older TVs, and many 32-inch models sold today, have a million or so pixels (720p). More recent and slightly larger TVs (typically 49 inches and smaller) have a little over 2 million pixels (1080p). Even newer and bigger TVs (typically 50 inches and above, although numerous smaller sizes too) have 8 million (for 4K Ultra HD). And the newest, largest and most ridiculously expensive TVs have over 33 million pixels (8K). You'll have to look very closely, or whip out a magnifying glass, to discern each one.

 

Here, CNET's TV reviewer David Katzmaier counts every pixel on an 8K TV.

Sarah Tew/CNET

Resolution is one of the most common specifications used to sell TVs, partly because "4K" and "8K" sound really high-tech and impressive. However, resolution is not the most important ingredient in picture quality. Just because a TV has higher resolution than another, doesn't always mean it looks better. It might, but not always, and for reasons that have little to do with resolution. A TV with better high dynamic range (HDR) performance, a better overall contrast ratio or better color will look better than one that just has more pixels.

That said, it's still worth understanding the various resolutions used by TV makers and others. Here's a bit more, ahem, detail.

Select large-screen resolutions

8K and 4K (Ultra HD)

When it comes to TVs, 4K and Ultra HD (or UHD) are referring to the same resolution. Those TVs, along with Ultra HD Blu-ray, and nearly all UHD streaming content from Netflix, Amazon and others, is 3,840x2,160 resolution.

One potential source of confusion is that 4K means something different whether you're talking about a TV in your home, or a projector in a theater. Technically, "4K" means a horizontal resolution of 4,096 pixels. This is the resolution set forth by the Digital Cinema Initiatives. Because movies vary in aspect ratio, which refers to the exact shape of the rectangle of screen, no vertical resolution is specified.

So Ultra HD TVs aren't technically "4K" by the specifications of DCI, but common parlance has usurped the term so "4K" TVs are 4K TVs even though their resolution is 3,840x2,160. Most companies just say both: Ultra HD 4K.

This shows the relative number of pixels in each of the major resolution formats. Not actual size of course; this is a chart not a visual representation (though it is to scale if you click on it).

From largest to smallest: 8K (tangerine), 4K Cinema in 1.78:1 aspect ratio (black); Ultra HD (white); 2K Cinema in 1.78:1 aspect ratio (green); Full HD 1080p (red); 720p (blue).

Geoffrey Morrison/CNET

8K follows the same logic. If you're talking about TVs, it's twice the horizontal and vertical resolution of 4K TVs: 7,680x4,320. This isn't a cinema resolution yet, at least not outside of the experimental stage. There are a handful of 8K TVs on the market, but it's going to be many years before this resolution is common. 

To get the most out of your 4K TV, you need 4K content. Fortunately, there's 4K content everywhere. Most of the major streaming services, like Netflix, Amazon, iTunes and Vudu all have 4K available. There are also Ultra HD Blu-ray players and gaming consoles , like the PS5 and Xbox Series X. If you have a PC, many video cards from the last few years can render games at 4K, with varying degrees of success.

We're starting to see the rollout of ATSC 3.0, now known as NextGen TV. With a NextGen TV tuner, or a TV with one built in, you'll theoretically be able to watch free 4K TV over the air. Just like the initial roll-out of HDTV at the turn of the century, it's going to be a while before 4K programming is common over the air.

The Samsung QN900D 8K QLED TV serves up slim styling and a host of AI-enhanced picture modes.

David Katzmaier/CNET

2K

Before "4K" became common, you'd almost never see "2K." It was pretty much just a cinema resolution, which is why you'll sometimes see 2K used to refer to a "master format." Most digital cinema projectors used in theaters are 2K resolution (some are less). It's 2,048 pixels wide, and again, no vertical resolution is specified by the DCI.

1080p or Full HD

Remember how we talked about digital cinema resolutions only specifying the horizontal resolution? Well TVs, on the other hand, have historically used the vertical to describe resolution (going back to the glass tube days). So 1080p is the vertical resolution. Nearly all HDTVs have an aspect ratio of 1.78:1 (16:9, aka widescreen), so that means a horizontal resolution of 1,920 pixels (1,920x1,080).

This is another source of confusion, since decades of TV discussions have talked about vertical resolutions, and then all of a sudden we're talking about "4K TVs," which refers to the horizontal resolution. Don't blame me, it wasn't my idea.

Which is why 1080p is not "1K." If anything, as mentioned above, it's "2K" by the same logic that UHD TVs are 4K. That said, most people don't call 1080p 2K; they call it 1080p or Full HD.

By the way, 1080i is the same resolution as 1080p, but no modern TV is 1080i. However, most HDTV broadcasts, including those from CBS and NBC, are still 1080i. 

720p

Roughly half the number of pixels of 1080p. It's rare to find a new TV that's 720p anymore. However, all ABC, Fox, ESPN, and their affiliated/sister channels broadcast at 720p. This goes back to the initial HD transition at the turn of the century. (And if you're wondering why your TV doesn't say "720p" on those channels, check this out.) It's also why this resolution is referred to as HD, while 1080p is Full HD or FHD for short.

Computer monitor resolutions: WUXGA, WXGA, WXXXGA, WXCBGBSA, WXLADYGAGA 

In the computer world they use an incomprehensible and shockingly un-user-friendly jumble of letters to describe resolution. Well, not "shockingly" since these are computers.

Look, I'm a computer guy, building my own PCs since the early '90s, and even I can't tell you what half these letters mean. I can understand that initially they were implemented to make things easier, but we've got so many resolutions and combinations that now they're just annoying.

Basically, for simple office monitors you'll mainly see FHD (1,920x1,080) and WUXGA (1,920x1,200), but you might also see a resolution of FHD Plus, which is typically 2,220x1,080 pixels. But as you go up in price and size, you'll find more variations in resolution. It's best not to get too hung up in the marketing terms and just focus on the numbers and if the resolution is high enough to meet your needs. For more details, you can dive into and print yourself a cheat sheet from this.

Samsung's CF791 ultrawidescreen monitor has 3,440x1,440 pixels, or UW-QHD (Ultra Wide Quad HD) resolution.

Sarah Tew/CNET

Bottom line

When you boil it all down, here's the takeaway: Older and smaller TVs are HD, 1080p. Nearly all new TVs are 4K Ultra HD, which have four times as many pixels as 1080p. Someday you might have an 8K or even 10K TV, but that's a l-o-o-o-o-ng way away.

Here's where I remind you that more pixels doesn't necessarily mean a better picture. There are other aspects of picture quality, such as contrast and color, that are far more important than resolution. 

In the future, resolution might become irrelevant. Technologies like MicroLED separate size and resolution, so your future 50-inch bedroom TV will have a radically different resolution than the 100-inch living room TV, as opposed to now where they'd both be 4K with different size pixels. Thanks to advancements in video processing, though, this won't matter. They'll all look sharp and detailed. 

First published in 2016. Regularly updated with new info.

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As well as covering TVs and other display tech, Geoff does photo tours of cool museums and locations around the world, including nuclear submarines, massive aircraft carriers, medieval castles, airplane graveyards, and more.   

You can follow his exploits on Instagram and YouTube about his 10,000-mile road trip. He also has written a bestselling sci-fi novel about city-size submarines, along with a sequel.