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!

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.

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.