The display aspect ratio (or DAR) is the aspect ratio of a display device and so the proportional relationship between the physical width and the height of the display. It is expressed as two numbers separated by a colon (x:y), where x corresponds to the width and y to the height. Common aspect ratios for displays, past and present, include 5:4, 4:3, 16:10, and 16:9.
To distinguish: The display aspect ratio (DAR) is calculated from the physical width and height of a display, measured each in inch or cm (Display size). The pixel aspect ratio (PAR) is calculated from the width and height of one pixel. The storage aspect ratio (SAR) is calculated from the numbers of pixels in width and height stated in the display resolution. Because the units cancel out, all aspect ratios are unitless.
Diagonal and area
The size of a television set or computer monitor is given as the diagonal measurement of its display area, usually in inches. Wider aspect ratios result in smaller overall area, given the same diagonal.
TVs
Most televisions were built with an aspect ratio of 4:3 until the late 2000s, when widescreen TVs with 16:9 displays became the standard. This aspect ratio was chosen as the geometric mean between 4:3 and 2.35:1, an average of the various aspect ratios used in film. While 16:9 is well-suited for modern HDTV broadcasts, older 4:3 video has to be either padded with bars on the left and right side (pillarboxed), cropped or stretched, while movies shot with wider aspect ratios are usually letterboxed, with black bars at the top and bottom.
Since the turn of the 21st century, many music videos began shooting on widescreen aspect ratio.
Computer displays
As of 2016, most computer monitors use widescreen displays with an aspect ratio of 16:9, although some portable PCs use narrower aspect ratios like 3:2 and 16:10 while some high-end desktop monitors have adopted ultrawide displays.
The following table summarises the different aspect ratios that have been used in computer displays:
† The aspect ratio is approximate.
History
4:3, 5:4 and 16:10
Until about 2003, most computer monitors used an aspect ratio of 4:3, and in some cases 5:4. For cathode ray tubes (CRTs) 4:3 was most common even in resolutions where this meant the pixels would not be square (e.g. 320×200 or 1280×1024 on a 4:3 display). Between 2003 and 2006, monitors with 16:10 aspect ratio became commonly available, first in laptops and later also in standalone computer monitors. Reasons for this transition was productive uses for such monitors, i.e. besides widescreen movie viewing and computer game play, are the word processor display of two standard A4 or letter pages side by side, as well as CAD displays of large-size drawings and CAD application menus at the same time. 16:10 became the most common sold aspect ratio for widescreen computer monitors until 2008.
16:9
In 2008, the computer industry started to move from 4:3 and 16:10 to 16:9 as the standard aspect ratio for monitors and laptops. A 2008 report by DisplaySearch cited a number of reasons for this shift, including the ability for PC and monitor manufacturers to expand their product ranges by offering products with wider screens and higher resolutions, helping consumers to more easily adopt such products and "stimulating the growth of the notebook PC and LCD monitor market".
By 2010, virtually all computer monitor and laptop manufacturers had also moved to the 16:9 aspect ratio, and the availability of 16:10 aspect ratio in mass market had become very limited. In 2011, non-widescreen displays with 4:3 aspect ratios still were being manufactured, but in small quantities. The reasons for this according to Bennie Budler, product manager of IT products at Samsung South Africa was that the "demand for the old 'Square monitors' has decreased rapidly over the last couple of years". He also predicted that "by the end of 2011, production on all 4:3 or similar panels will be halted due to a lack of demand."
In 2012, 1920×1080 was the most commonly used resolution among Steam users. At the same time, the most common resolution globally was 1366×768, overtaking the previous leader 1024×768. In 2021, the 2K resolution of 1920×1080 was used by two thirds of the Steam users for the primary display with 1366×768 and 2560×1440 both at about eight percent taking the majority of the remaining resolutions.