What Does Smartphone Display Resolution Mean?

One of the biggest talking points of smartphone displays is the resolution. You’ll often hear terms such as HD and Full HD, or 2K and 4K being thrown around when people talk about mobile phone display specs.

To the unknowing, those terms can sound like just letters and numbers, but those letters and numbers are very important because they give you an indication of how well the display is going to reproduce an image. They refer to the display’s resolution.

The term resolution refers to the number of pixels on a display. It is often displayed as width by height, e.g. 1920×1080. That means the display’s width contains 1 920 pixels and the height has 1 080 pixels, for a total of 2 073 600 pixels. The more pixels a display has, the higher the resolution. High-resolution displays have the capacity to display more visual information, which results in clear picture-quality with great detail.

If you’re still unsure about what any of that means, then I suggest you read on for more clarity. Let’s start by explaining pixels.

What are pixels?

Pixels are the very tiny red, blue, and green blocks or dots that make up a digital display. The word ‘pixel’ comes from the combination of the words “pix” (from ‘picture’) and “el” (from ‘element’). Therefore, pixels are the picture elements that make up a digital image.

Close-up of an LCD display

If you magnify the surface of a smartphone screen, you will notice many tiny blocks or dots of colour. These are pixels. The more pixels there are, the more detail you get.

The pixel resolution of a smartphone display should not be confused with that of the camera’s image sensor. Although they’re essentially the same in principle, the camera sensor’s pixels have little to do with the display resolution.

A camera’s resolution is referred to in megapixels (e.g., 12MP) when taking photos, whereas people use resolution names such as HD and 4K when talking about screen resolution and video recording.

ALSO READ: Smartphone Camera Megapixels: The REAL Truth Explained

Is the resolution the size of the display?

Resolution is not to be confused with the physical size of the display. Resolution and display size are not the same thing. The size of a display is measured diagonally and expressed in inches, e.g. 6.2-inches.

The resolution of a display is derived from multiplying the number of pixels in the width of the display by the number of pixels in the height of the display, e.g, 1920 x 1080. However, the resolution of a display is not expressed as the total number of pixels on the screen, but rather in HD standards, which I will discuss later.

It is possible for two displays that are physically different in size to have the same resolution or number of pixels. That’s why, when looking at the quality of a display, it’s also important to know the pixel density and understand how it affects the picture, as well.

Standard smartphone display resolutions

High Definition (HD)

The term ‘HD’ is based on the original resolutions of HDTV, where the most basic of the handful of high definition resolutions was 1280 x 720 pixels high and was shortened to 720p. This was referred to as high definition because standard definition (SD) had a lower resolution (480p), and was not as sharp as HD.

On smartphones, an HD display is typically 1280 x 720 pixels or anything above that but below Full HD. Some manufacturers refer to this as HD+.

Full HD (FHD)

Before 2K displays were introduced in television sets, the highest display resolution you could get was 1920 x 1080 pixels. This was known as full high-definition or Full HD aka FHD.

A lot of entry-level and mid-range smartphones come equipped with a Full HD display. It offers greater resolution than basic HD, which makes for a better viewing experience. Larger and more expensive phone models tend to have higher resolutions.

Full HD+ or FHD+ is used to refer to smartphone displays that are larger than the standard 1920 x 1080 resolution of HD displays but fall below the 2K resolution threshold.

2K, Quad HD (QHD/WQHD)

Quad HD gets its name from the fact that it is four times the resolution of basic HD. In other words, you can fit four 720p displays in one QHD display.

But don’t confuse QHD for qHD (with a small “q”). qHD stands for Quarter High Definition and, as the name suggests, is only 1/4 of 1080p Full HD (960 x 540 pixels).

On the other hand, WQHD (Wide Quad High Definition) is no different to QHD. Some manufacturers choose to put the “W” in front to emphasize that it has a wide aspect ratio.

2K is also another way of referring to a QHD display. This comes from the fact that the largest dimension of the 2560 x 1440 pixel resolution is above 2000 pixels.

4K, Ultra HD (UHD)

First of all, a smartphone 4K display is not double the resolution of a 2K display. In fact, it’s not “true” 4K in the cinematic sense. Real 4K displays have a resolution of 4096 x 2160 pixels and are used in professional productions and digital cinemas.

Smartphone 4K, on the other hand, has a resolution of 3840 x 2160, which is 4x the resolution of 1080p Full HD. It is sometimes referred to as UHD (Ultra High Definition) or 4K UHD to differentiate it from true 4K.

What is pixel density?

Expressed in pixels per inch (PPI), pixel density refers to the concentration of pixels in an area of an inch on a particular display. A high pixel density means that a lot of pixels are packed together in the space of an inch. The higher the pixel density, the sharper the display will be.

Pixel density depends on two things– the physical size of the display and the resolution. Two smartphones with Full HD displays can have different pixel densities depending on the physical size of the screen.

For example, although a 5.5-inch Full HD mobile screen has the same number of pixels as a 6.5-inch Full HD display, the smaller display will have a higher pixel density because it has to squeeze in the same number of pixels (1920 x 1080 pixels) onto a smaller screen.

The 5.5-inch display will have a pixel density of about 401ppi compared to the 339ppi of a 6.5-inch Full HD display. The pixel densities are different because the sizes of the screens are different. Therefore, the larger display will have larger, but fewer pixels per inch.

Because of the higher concentration of pixels per inch, the 5.5-inch screen can appear clearer and more detailed than the 6.5-inch display but that doesn’t mean the resolutions are any different.

It is widely believed that 300ppi is the sweet spot for mobile phone pixel density because your eyes won’t be able to see the individual pixels on the screen, making the display look very realistic. This is the idea Apple termed ‘retina display’ and introduced with the iPhone 4.

Source: geekcosmos.com

In the infographic above, you can see that the iPhone 3GS and the iPhone 4 both had the same 3.5-inch screen size but different pixel densities. The iPhone 3 had a pixel density of 163ppi but the iPhone 4 had double the pixel density at 326ppi.

That’s because the iPhone 4 had a larger resolution of 640 x 960 compared to the 360 x 480 display resolution of the iPhone 3GS. So, more pixels were squeezed into the same size screen to create the retina display.

Conclusion

So, what does display resolution mean? It refers to the number of pixels on a screen, and not the physical size of the screen. Two displays of different sizes can have the same display resolution but the pixel density will be different.

For the best picture quality, a large smartphone display should have a high resolution, otherwise, the pixel density will drop and the quality of the display will suffer.

Anybody can benefit from a good quality display. But if you’re into mobile photography, mobile gaming, or mobile videography, then you should definitely pay attention to the resolution and other display specs when buying a phone for such graphics-related activities.