Aspect ratio
The aspect ratio of a geometric shape is the ratio of its sizes in different dimensions. For example, the aspect ratio of a rectangle is the ratio of its longer side to its shorter side  the ratio of width to height,^{[1]} when the rectangle is oriented as a "landscape".
The aspect ratio is expressed as two numbers separated by a colon (x:y). The values x and y do not represent actual width and height but, rather, the "relation" between width and height. As an example, 8:5, 16:10 and 1.6:1 are the same aspect ratio.
In objects of more than two dimensions, such as Hyperrectangles, the aspect ratio can still be defined as the ratio of the longest side to the shortest side.
Contents
 Applications and uses 1

Aspect ratios of simple shapes 2
 Rectangles 2.1
 Ellipses 2.2
 Aspect ratios of general shapes 3
 Notations 4
 See also 5
 References 6
 External links 7
Applications and uses
The term is most commonly used with reference to:

Graphic / image
 Image aspect ratio
 Display aspect ratio: the aspect ratio for computer displays.
 Paper size
 Standard photographic print sizes
 Motion picture film formats
 Standard ad size
 Pixel aspect ratio

Photolithography: the aspect ratio of an etched, or deposited structure is the ratio of the height of its vertical side wall to its width.
 HARMST High Aspect Ratios allow the construction of tall structures without slant
 Tire code
 Tire sizing
 Wing aspect ratio of an aircraft or bird
 Astigmatism of an optical lens
 Nanorod dimensions
Aspect ratios of simple shapes
Rectangles
For a rectangle, the aspect ratio denotes the ratio of the width to the height of the rectangle. A square has the smallest possible aspect ratio of 1:1.
Examples:
 4:3 = 1.3: Some (not all) 20th century computer monitors (VGA, XGA, etc.), standarddefinition television
 √2:1 = 1.414…: International paper sizes (ISO 216)
 3:2 = 1.5: 35mm still camera film, iPhone (until iPhone 5) displays
 16:10 = 1.6 (not shown above): Commonly used widescreen computer displays (WXGA)
 Φ:1 = 1.618…: Golden ratio, close to 16:10
 5:3 = 1.6: Super 16 mm, a standard film gauge in many European countries
 16:9 = 1.7: Widescreen TV
Ellipses
For an ellipse, the aspect ratio denotes the ratio of the major axis to the minor axis. An ellipse with an aspect ratio of 1:1 is a circle.
Aspect ratios of general shapes
In geometry, there are several alternative definitions to aspect ratios of general compact sets in a ddimensional space:^{[2]}
 The DiameterWidth Aspect Ratio (DWAR) of a compact set is the ratio of its diameter to its width. A circle has the minimal DWAR which is 1. A square has a DWAR of sqrt(2).
 The CubeVolume Aspect Ratio (CVAR) of a compact set is the dth root of the ratio of the dvolume of the smallest enclosing axesparallel dcube, to the set's own dvolume. A square has the minimal CVAR which is 1. A circle has a CVAR of sqrt(2). An axisparallel rectangle of width W and height H, where W>H, has a CVAR of sqrt(W^2/WH) = sqrt(W/H).
If the dimension d is fixed, then all reasonable definitions of aspect ratio are equivalent to within constant factors.
Notations
Aspect ratios are mathematically expressed as x:y (pronounced "xtoy") and x×y (pronounced "xbyy"), with the latter particularly used for pixel dimensions, such as 640×480.
Cinematographic aspect ratios are usually denoted as a (rounded) decimal multiple of width vs unit height, while photographic and videographic aspect ratios are usually defined and denoted by whole number ratios of width to height. In digital images there is a subtle distinction between the Display Aspect Ratio (the image as displayed) and the Storage Aspect Ratio (the ratio of pixel dimensions); see Distinctions.
See also
 Ratio
 Equidimensional ratios in 3D
 List of film formats
 Vertical orientation
References
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 ^
External links
 Aspect ratio calculator, an interactive tool for calculating aspect ratio of objects
