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TV resolution confusion: 1080p, 2K, UHD, 4K, 8K, and what they all mean

Is 4K twice is good as 2K? Is it different from Ultra HD? Is 1080p 1K? What do all these random numbers mean?

Geoffrey Morrison/CNET

One of first numbers you'll see when you're shopping for a new TV -- right after the screen size and the price -- is the resolution. Unfortunately, it's one of the more confusing numbers too.

Here are some common questions you might have about resolution, along with our quick answers.

  • What does 4K mean? It depends, but usually 3,840x2,160 pixels.
  • What does UHD mean? It stands for "Ultra High Definition," but it 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.

Looking for more information about TV resolution? Let's start at the beginning.

What is 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.

015-lg-oled-tv-8k15

8K resolution offers four times the number of pixels as 4K (UHD). 

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's 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

Resolution name Horizontal x vertical pixels Other names Devices
8K 7,680x4,320 8K UHD TVs
"Cinema" 4K 4,096x[unspecified] 4K Projectors
UHD 3,840x2,160 4K, Ultra HD, Ultra-High Definition TVs, monitors
2K 2,048x[unspecified] none Projectors
WUXGA 1,920x1,200 Widescreen Ultra Extended Graphics Array Monitors, projectors
1080p 1,920x1,080 Full HD, FHD, HD, High Definition TVs, monitors
720p 1,280x720 HD, High Definition TVs

4K or Ultra HD

The most common resolution for new TVs is 4K. Since it's unfamiliar to many people, it's also the source of the vast majority of the confusion about TV resolution.

The short version is this: 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 problem 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 yes, the pedants are correct. Ultra HD TVs aren't technically "4K" since their resolution is 3,840x2,160. However, it doesn't matter. 4K is way easier to say than 2,160p or Ultra HD, and when anyone runs a survey asking about it, the vast majority of you (and us, FWIW), greatly prefer "4K." So do Google. Amazon and most TV makers, all of which just use both.

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: 4K Cinema, in 1.78:1 aspect ratio (black); UHD (white); 2K Cinema, in 1.78:1 aspect (green); Full HD 1080p (red); 720p (blue).

Geoffrey Morrison/CNET

Since the pixel difference is 13 percent and it's nearly impossible to see even larger differences, we'll file this under "why does anyone care?"

Sony's home 4K projectors, on the other hand, are actually 4K. The best picture I've ever seen in a theater was a 4K projector with lasers.

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. We're starting to see 8K TVs hit the market, but it's going to be many years before this resolution is common. 

Right now you can find 4K content in many places. 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 PS4 Pro and Xbox One X. If you have a PC, most video cards from the last few years can render games at 4K, with varying degrees of success. On the other hand, there's no US broadcast TV in 4K. We'll have to wait until ATSC 3.0 for 4K over-the-air. For cable and satellite there are some options from some providers, but this is currently only a couple of channels of movies and documentaries. Which is to say, primetime shows on ABC, CBS, NBC, and Fox are not in 4K, and there's no clear indication when they might be.

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 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.

But now that "4K" has gained traction as a term used to describe TVs and content, "2K" is becoming increasingly common as shorthand for the 1080p resolution used by most HDTVs, as well as Blu-ray. It's not technically accurate, but that didn't stop "4K" from becoming more popular than "UHD."

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.

That means 1080p is not "1K." If anything, it's "2K." Or it is 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 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.

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, the ones you're most likely to see are FHD (1,920x1,080) and WUXGA (1,920x1,200). The rest, you can dive into and print yourself a cheat sheet from this.

Fortunately, the only time most of you will come across this letter goulash is if you're looking for a cheap data projector or a computer monitor.

There are also computer monitors that have unique resolutions like 5K (5,120x2,880) or ultrawidescreen 21:9 aspect ratios with crazy resolutions like 3,440x1,440. There are so many variations we couldn't hope to cover them all. 

samsung-cf791

Samsung's CF791 ultrawidescreen monitor has 3440x1440 pixels, or UW-QHD (Ultra Wide Quad HD) resolution.

Sarah Tew/CNET

Bottom line

When you boil it all down, here's the takeaway: Your current TV (unless you bought it in the last few years) is HD, 1080p. Newer 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 we 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. And one would be a projector. Thanks to advancements in video processing, though, this won't matter. They'll all look sharp and detailed. 

Update Feb. 7, 2019: This story first appeared in January, 2016. It has been updated to reflect new information and advancements.


Got a question for Geoff? First, check out all the other articles he's written on topics like why all HDMI cables are the sameTV resolutions explainedLED LCD vs. OLED and more.

Still have a question? Tweet at him @TechWriterGeoff, then check out his travel photography on Instagram. He also thinks you should check out his best-selling sci-fi novel and its sequel