UHD and HDR: Everything you need to know

Welcome to the vast world of TV acronyms! Let’s look at two very common terms that you will frequently run across when shopping for a new display: UHD and HDR. Yes, these terms both have “HD” in them, but how are they related? Which matters most when buying? Do you need them both? Let’s go over the common questions about UHD vs. HDR, and everything you should know!

The Sony A90J OLED TV.
Sony

What does UHD mean?

UHD stands for Ultra High Definition, a label for how many pixels a display has. This is in contrast to the older term FHD, or Full High Definition, which you may also know as 1080p (while HD is typically the lower-res 720p), referring to a pixel count of 1920 x 1080 pixels.

According to the Consumer Technology Association (CTA), Ultra High Definition is defined as anything having a minimum resolution of 3840×2160 pixels. This is an upgrade for your TV because greater pixel density means a crisper picture with more detail. The larger the TV, the more it typically benefits from a UHD resolution, although other factors, like how close the viewers are to the screen, also play a part.

Is UHD the same as 4K?

Not exactly. 4K is under the UHD umbrella, as is 8K, but it’s actually a specification created by the DCI — Digital Cinema Initiatives — referring to a horizontal pixel count of 4,000 (it’s actually slightly more, but rounded down) along with some specific encoding standards. It’s also a format that must be supported by devices like set-top boxes in order to function. We have a guide explaining it further here.

4K is common on TVs, but it’s not the only UHD resolution available. Some displays, especially computer monitors, are UHD but with different numbers of pixels — as long as they are higher than 1080p, they can qualify as UHD. Higher resolutions, like 8K, also count as UHD.

Over time, the two terms have become lumped together and may be treated interchangeably, which can lead to confusion. The size and shape of TVs mean they are almost always 4K, but you can check for the label if you want to make sure. Brands have begun to use the full label “4K UHD” to help avoid confusion.

TV resolution chart.

OK, so what is HDR?

HDR stands for High-Dynamic Range. This is a separate feature from UHD that has nothing to do with pixel count: Instead, it refers to an optimization technology that adjusts contrast, brightness, and color to designated levels for the ideal visual experience. It makes the TV image richer and more realistic — but requires content that has the right HDR metadata to tell the TV what to do. HDR content is found on everything from streaming apps to Blu-rays, and includes both movies and games. The technology also makes adjusting between TV modes like “movie” or “vivid” largely unnecessary.

Finally, HDR requires a broader color gamut and brightness range than older TVs, so it indicates a general upgrade for TV models compared to TVs that lack the technology.

Is there more than one type of HDR?

Yes, there are multiple versions of HDR. HDR10 is currently the most common, an open standard used by a variety of content producers, followed by Dolby’s proprietary option called Dolby Vision, which allows for even more detailed optimization. Other HDR standards include HDR10+, which is gaining in popularity, and Advanced HDR, a standard created by Technicolor. They all work by sending content metadata to your TV to tell it what brightness and color settings it needs and when to change them.

Do you need UHD for HDR or vice-versa?

You do not. They are separate features on a display and do not depend on each other. UHD requires more pixels in the TV panel, while HDR requires enhanced brightness and color capabilities.

Can a TV have both UHD and HDR?

Yes, and it’s common these days. Both are significant upgrades from TVs in the past, so it makes sense to bundle them together for an overall improved experience. If you browse today’s best 4K UHD TVs, for example, you will find some type of HDR on all of them.

Hisense U8G 4K ULED HDR TV remote.
Riley Young/Digital Trends

Can I add UHD or HDR to an older TV?

You cannot. These are native features that cannot be added to a TV post-manufacturing. Additionally, keep in mind that your other hardware also needs to support HDR and UHD playback if you are running video through it. And while UHD/HDR displays and streaming media are needed to view UHD/HDR content, these devices are also backward compatible with all non-UHD/non-HDR content sources, too. Movies, games, and other content will typically be labeled so you can tell.

Are these two terms related in any other way?

No. Even the “HD” in their names is a red herring: One stands for High Definition, and the other stands for High-Dynamic. They are only related in that they’re video technologies that can improve the visuals on your TV.

What’s more important when shopping for a TV?

They’re both great things to look for, and since most UHD TVs these days come with some version of HDR, you probably won’t need to choose between them. If you ever do, HDR is generally more beneficial for color optimization — it makes visuals look great. UHD adds more pixels — it gives visuals more detail. Your personal preference matters here, but it’s a good idea to think about how you use your TV. For example, sports fans may benefit more from UHD resolutions, while gamers may enjoy the effects of HDR a bit more.

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