4K resolution refers to a display resolution of approximately 4,000 pixels wide. It is one of the most common ultra-high-definition television and monitor resolutions. But instead of being called 2160p, which would be consistent with other video formats like 1080p and 720p, it is referred to as 4K. This can cause some confusion, especially when comparing 4K to other resolutions. In this article, we’ll look at the reasons why 4K is called 4K instead of 2160p.
Common Video Resolutions
To understand why 4K isn’t called 2160p, it helps to first look at some common video resolutions and their naming conventions:
| Resolution | Name | Pixel Dimensions |
| 480i/480p | Standard Definition (SD) | 720 x 480 pixels |
| 720p | High Definition (HD) | 1280 x 720 pixels |
| 1080i/1080p | Full High Definition (FHD) | 1920 x 1080 pixels |
| 1440p | Quad HD (QHD) | 2560 x 1440 pixels |
| 2160p | 4K UHD | 3840 x 2160 pixels |
As you can see, video resolutions are often referred to by their vertical pixel count, followed by “i” for interlaced or “p” for progressive scan. So a resolution of 1080 horizontal pixels with progressive scan would be 1080p.
Following this convention, a resolution of 2160 vertical pixels with progressive scan would be called 2160p. So why isn’t 4K, with its vertical resolution of 2160 pixels, called 2160p?
Origins of the Name “4K”
To understand why 4K isn’t called 2160p, we need to look at the origins of the “4K” name.
The name “4K” was originally derived from the roughly 4,000 horizontal pixels in these ultra-high-definition resolutions. The first 4K resolutions had widths of approximately 4,000 pixels, give or take a few hundred pixels depending on the exact aspect ratio.
Some key moments in the history of the 4K name:
- In the early 2000s, Sony and JVC introduced resolution formats with horizontal resolutions near 4,000 pixels like 4096 x 2160.
- These were sometimes marketed as “4K” resolution since they were close to 4000 pixels wide.
- In 2007, the Digital Cinema Initiatives (DCI) standardize a 4096 x 2160 resolution for digital cinema projection at 4K.
- In 2009, Sony introduced a 4K resolution of 3840 x 2160 for consumer televisions which retained the “4K” name.
- Television manufacturers and others gradually adopted the consumer 3840 x 2160 format as the standard 4K resolution.
As you can see, the origins of “4K” are rooted in these early ultra-high-definition formats having close to 4,000 pixels horizontally. This led to the widespread use of “4K” as the name for consumer 2160p televisions, even though they didn’t have exactly 4,000 pixels horizontally.
Advantages of Keeping the “4K” Name
Once the name “4K” became standard, there were some advantages to keeping this name rather than switching to “2160p”:
- Consistency – By the late 2000s, “4K” was already a well-known shorthand for ultra-high-def resolutions in the consumer space.
- Differentiation – Using “4K” distinguished these new resolutions from existing formats like 1080p.
- Simplicity – “4K” is short and easy to say and remember.
- Precision – The industry standard for 4K UHD is 3840 x 2160, which is not precisely 2160 vertical pixels.
For these reasons, the industry continued to use “4K” as the name even after the standard resolution became 3840 x 2160. The name was already established and had advantages over switching to “2160p” as a new moniker.
Is 3840 x 2160 the True 4K Resolution?
This highlights an interesting quirk around 4K resolutions – the consumer standard of 3840 x 2160 is sometimes referred to as “4K UHD” while 4096 x 2160 is called “DCI 4K.”
So which resolution is the “true” 4K? 4096 x 2160 fits closest to having a horizontal width of 4000 pixels. But 3840 x 2160 became the mainstream consumer standard.
Arguments for 3840 x 2160 Being “True” 4K
- It’s the overwhelming standard for 4K consumer TVs, monitors, cameras, etc.
- Having exactly 4,000 pixels horizontally isn’t required to be called “4K.” The name is shorthand for “close to 4,000 pixels.”
- It’s still nearly 4000 pixels wide (3840 is 96% of 4000).
Arguments for 4096 x 2160 Being “True” 4K
- It matches closest to the origin of the “4K” name as being near 4000 pixels.
- It’s sometimes called “DCI 4K” referring to the Digital Cinema Initiatives.
- Some argue it’s the only resolution that should technically be called “4K.”
There are good arguments on both sides. Overall, both resolutions fit into the general “4K” designation since they have close to 4000 pixels horizontally. But from a technical perspective, 4096 x 2160 is closest to the original meaning of “4K” resolution.
Should We Call It 2160p Instead of 4K?
Given that the common 4K resolution of 3840 x 2160 isn’t precisely 4000 pixels wide, would it make more sense to call it “2160p” based on the vertical resolution?
Here are some pros and cons to consider:
Potential Pros of Switching to “2160p”
- It would be consistent with other resolution naming conventions.
- It reflects the precise vertical resolution of 2160 lines.
- Might reduce confusion between 3840 x 2160 and 4096 x 2160 as the “true” 4K.
Potential Cons of Switching to “2160p”
- “4K” is universally established after over a decade of usage.
- Switching names would cause confusion and extra terminology.
- 3840 x 2160 isn’t exactly 2160 vertical lines either (it’s 2160.54 lines).
Given the universal use of “4K” in the market, switching to “2160p” seems unlikely barring an coordinated effort from major manufacturers and standards bodies. But it highlights the interesting history and technicalities around the “4K” name as it has evolved over the past 20 years.
4K Display Standards
When talking about 4K, it’s also important to distinguish between different 4K-related display standards:
| Standard | Resolution | Aspect Ratio |
| DCI 4K | 4096 x 2160 | 256:135 (~1.9:1) |
| 4K UHD | 3840 x 2160 | 16:9 |
| 4K DCI | 4096 x 1716 | 256:135 (~1.9:1) |
| Apple 4K | 4096 x 2304 | 16:9 |
As you can see, resolutions near or at 4000 pixels wide are often called “4K”, but have some variations in dimensions and aspect ratios. So when comparing 4K devices, it’s important to look at the specific resolution and aspect ratio rather than just assuming “4K” means 3840 x 2160.
4K Resolution and Bit Depth
Along with resolution, bit depth is another important specification for 4K video. Bit depth determines the number of color values possible for each pixel. Common bit depths for 4K include:
- 8-bit color: 16.7 million colors
- 10-bit color: 1.07 billion colors
- 12-bit color: 68.7 billion colors
Higher bit depth allows for more subtle and precise colors. So 4K video encoded with 10-bit or 12-bit color can produce more vibrant and lifelike colors than 8-bit video. When comparing 4K devices, factors like bit depth can be just as important as raw resolution.
4K Content Sources
To take advantage of 4K displays, you need access to 4K content. Here are some common sources for 4K video:
- Streaming – Netflix, Amazon, YouTube and others offer some shows and movies in 4K.
- Physical Media – 4K Blu-ray discs and players provide 4K movies with high bit rates.
- Gaming – Xbox One X, PS4 Pro, and high-end PCs can play games in 4K.
- Cameras – Many late model DSLR, mirrorless, smartphone and video cameras can record 4K.
When upgrading to a 4K TV or display, it’s good to consider what sources you’ll use to watch 4K content regularly. If you won’t have much 4K content, the extra resolution may not provide much benefit.
4K Gaming Requirements
To play modern games at 4K resolution requires some high-end gaming hardware. Here are some typical system requirements for 4K gaming:
- GPU – High-end recent generation GPU like RTX 3080 or Radeon 6800 XT
- CPU – Mid-range processor like Intel i5 or Ryzen 5 from the last 2-3 generations
- RAM – 16GB or higher
- Storage – SSD or high speed hard drive
- OS – Windows 10 64-bit or latest console OS
- Display – 4K monitor or TV
Lower resolution gaming is much more forgiving. But to render complex modern games at 4K resolution while achieving smooth 60fps gameplay requires top-tier PC components or the latest consoles.
4K vs 1080p – Is It Worth It?
For many consumers debating an upgrade, a key question is how much better 4K is compared to 1080p. Here are some comparisons between 4K and 1080p:
| 4K (2160p) | 1080p | |
| Resolution | 3840 x 2160 | 1920 x 1080 |
| Total Pixels | 8,294,400 | 2,073,600 |
| Pixel Density | Higher | Lower |
| Sharpness | Extremely sharp | Sharp |
| Ideal Screen Size | 55″+ | 32″- 55″ |
The much higher resolution of 4K provides sharper image quality, finer detail, and an immersive visual experience, especially on larger screen sizes. But you need 4K source material to fully enjoy these benefits.
For smaller screens under 40″, 4K may not provide a huge advantage over 1080p when sitting at typical viewing distances. On screens 50″ and up, 4K becomes more noticeable and beneficial.
So depending on your screen size, viewing distance, and availability of 4K content, upgrading from 1080p to 4K may or may not be worth it for you.
4K vs 1440p
Another common question is how 4K compares to 1440p, commonly found on gaming monitors. Here’s a quick rundown:
| 4K (2160p) | 1440p | |
| Resolution | 3840 x 2160 | 2560 x 1440 |
| Aspect Ratio | 16:9 | 16:9 |
| Pixel Count | 8.3 million | 3.7 million |
| Sharpness | Extremely sharp | Very sharp |
| Gaming Performance | More demanding | Easier to run |
The much higher resolution of 4K provides sharper clarity. But it’s more taxing for gaming. 1440p is easier to run at high frame rates but still provides excellent visuals. For many gamers, 1440p provides a good middle ground.
Is 8K Better Than 4K?
Televisions and other devices with even higher 8K resolutions (around 8000 pixels wide) are also beginning to hit the market. But is 8K substantially better than 4K?
In terms of raw resolution, 8K quadruples the pixels of 4K, allowing for unprecedented sharpness and detail. But there are some limitations:
- Very little 8K content is available to consumers right now.
- HDMI 2.1 and other modern connections are required to transmit 8K video.
- Small screens under 65″ won’t benefit much from 8K.
- You typically need to be very close to an 8K screen to resolve the additional detail.
- 8K requires 4x the processing power of 4K for gaming and video.
For large-screen TVs, 8K can provide some advantages over 4K when viewing from close distances. But for most consumers, 4K remains the better choice right now due to wider content availability and lower hardware requirements. 8K may become more mainstream in 5-10 years.
Conclusion
While not exactly 4,000 pixels wide, the name “4K” has stuck as the shorthand for ultra-high-def resolutions like 3840 x 2160. The term originated from early formats near 4,000 pixels and provided benefits over switching to a name like “2160p” once established.
4K provides substantially sharper images than 1080p, especially on larger screens, and is becoming widespread across TVs, monitors, cameras, games, and videos. But you need native 4K source material to enjoy the full benefits.
For many consumers, 4K remains the ideal blend of high resolution and more feasible hardware requirements. But early adopters can benefit from even greater sharpness and detail with 8K displays. Regardless, from 1080p to 4K to 8K, screen resolutions continue to evolve to provide the sharpest and most lifelike visual experiences possible.
