Aspect ratio
Encyclopedia
The aspect ratio of a shape
Shape
The shape of an object located in some space is a geometrical description of the part of that space occupied by the object, as determined by its external boundary – abstracting from location and orientation in space, size, and other properties such as colour, content, and material...

is the ratio of its longer dimension
Dimension
In physics and mathematics, the dimension of a space or object is informally defined as the minimum number of coordinates needed to specify any point within it. Thus a line has a dimension of one because only one coordinate is needed to specify a point on it...

to its shorter dimension. It may be applied to two characteristic dimensions of a three-dimensional shape, such as the ratio of the longest and shortest axis, or for symmetrical objects that are described by just two measurements, such as the length and diameter of a rod. The aspect ratio of a torus
Torus
In geometry, a torus is a surface of revolution generated by revolving a circle in three dimensional space about an axis coplanar with the circle...

is the ratio of the major axis R to the minor axis r.

## Applications and uses

The term is most commonly used with reference to:
• Graphic / image
• Image aspect ratio
Aspect ratio (image)
The aspect ratio of an image is the ratio of the width of the image to its height, expressed as two numbers separated by a colon. That is, for an x:y aspect ratio, no matter how big or small the image is, if the width is divided into x units of equal length and the height is measured using this...

• Display aspect ratio
Display aspect ratio
The Aspect ratio of a display is the fractional relation of the width of the display area compared to its height.The aspect ratio is expressed as two numbers separated by a colon...

- The aspect ratio for computer displays.
• Paper size
Paper size
Many paper size standards conventions have existed at different times and in different countries. Today there is one widespread international ISO standard and a localised standard used in North America . The paper sizes affect writing paper, stationery, cards, and some printed documents...

• Standard photographic print sizes
Standard photographic print sizes
Standard photographic print sizes are used in photographic printing. Cut sheets of paper meant for printing photographs are commonly sold in these sizes....

The Universal Ad Package is a set of four ad sizes that all compliant member publishers have agreed to support for Internet advertising. This standard is published by the Interactive Advertising Bureau.* 300 x 250 -...

• Pixel aspect ratio
Pixel aspect ratio
Pixel aspect ratio is a mathematical ratio that describes how the width of a pixel in a digital image compares to the height of that pixel....

• Photolithography
Photolithography
Photolithography is a process used in microfabrication to selectively remove parts of a thin film or the bulk of a substrate. It uses light to transfer a geometric pattern from a photomask to a light-sensitive chemical "photoresist", or simply "resist," on the substrate...

: the aspect ratio of an etched, or deposited structure is the ratio of the height of its vertical side wall to its width.
• HARMST
HARMST
HARMST is an acronym for High Aspect Ratio Microstructure Technology that describes fabrication technologies,used to create high-aspect-ratio microstructures with heights between tens of micrometers up to a centimeter and aspect ratios greater than 10:1...

High Aspect Ratios allow the construction of tall structures without slant
• Tire code
Tire code
Automobile tires are described by an alphanumeric tire code or tyre code , which is generally molded into the sidewall of the tire. This code specifies the dimensions of the tire, and some of its key limitations, such as load-bearing ability, and maximum speed...

• Tire sizing
Tire sizing
Plus sizing is the practice of changing a specific tire to a larger size while compensating with reductions in other aspects of the tire's size so that the new tire has the same diameter and circumference as the original tire to prevent any changes in speedometer accuracy, torque and traction...

• wing aspect ratio
Aspect ratio (wing)
In aerodynamics, the aspect ratio of a wing is essentially the ratio of its length to its breadth . A high aspect ratio indicates long, narrow wings, whereas a low aspect ratio indicates short, stubby wings....

of an aircraft
Aircraft
An aircraft is a vehicle that is able to fly by gaining support from the air, or, in general, the atmosphere of a planet. An aircraft counters the force of gravity by using either static lift or by using the dynamic lift of an airfoil, or in a few cases the downward thrust from jet engines.Although...

or bird
Bird
Birds are feathered, winged, bipedal, endothermic , egg-laying, vertebrate animals. Around 10,000 living species and 188 families makes them the most speciose class of tetrapod vertebrates. They inhabit ecosystems across the globe, from the Arctic to the Antarctic. Extant birds range in size from...

• Astigmatism
Astigmatism
An optical system with astigmatism is one where rays that propagate in two perpendicular planes have different foci. If an optical system with astigmatism is used to form an image of a cross, the vertical and horizontal lines will be in sharp focus at two different distances...

of an optical lens

### Rectangles

For a rectangle, the aspect ratio denotes the ratio of length to width of the rectangle. An aspect ratio of 1:1 is a square.
From left to right:
• 1. = 4:3: Some (not all) 20th century computer monitors (VGA, XGA, etc.), standard-definition television
Standard-definition television
Sorete-definition television is a television system that uses a resolution that is not considered to be either enhanced-definition television or high-definition television . The term is usually used in reference to digital television, in particular when broadcasting at the same resolution as...

• 1.414… = √2:1: International paper sizes (ISO 216
ISO 216
ISO 216 specifies international standard paper sizes used in most countries in the world today. It defines the "A" and "B" series of paper sizes, including A4, the most commonly available size...

)
• 1.5 = 3:2: 35 mm film
35 mm film
35 mm film is the film gauge most commonly used for chemical still photography and motion pictures. The name of the gauge refers to the width of the photographic film, which consists of strips 35 millimeters in width...

, iPhone displays
• 1.6 = 16:10, widely used widescreen
Widescreen
Widescreen images are a variety of aspect ratios used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than the standard 1.37:1 Academy aspect ratio provided by 35mm film....

computer display
Computer display
A monitor or display is an electronic visual display for computers. The monitor comprises the display device, circuitry, and an enclosure...

s (WXGA)
• 1.618…: Golden ratio
Golden ratio
In mathematics and the arts, two quantities are in the golden ratio if the ratio of the sum of the quantities to the larger quantity is equal to the ratio of the larger quantity to the smaller one. The golden ratio is an irrational mathematical constant, approximately 1.61803398874989...

, close to 16:10
• 1. = 5:3: super 16 mm, a standard film gauge
Film gauge
Film gauge is a physical property of photographic or motion picture film stock which defines its width. Traditionally the major film gauges in usage are 8 mm, 16 mm, 35 mm, and 65/70 mm...

in many European countries
• 1. = 16:9: widescreen
Widescreen
Widescreen images are a variety of aspect ratios used in film, television and computer screens. In film, a widescreen film is any film image with a width-to-height aspect ratio greater than the standard 1.37:1 Academy aspect ratio provided by 35mm film....

TV

### Ellipses

For an ellipse, the aspect ratio denotes the ratio of the major axis to the minor axis. An aspect ratio of 1:1 is a circle.

• Ratio
Ratio
In mathematics, a ratio is a relationship between two numbers of the same kind , usually expressed as "a to b" or a:b, sometimes expressed arithmetically as a dimensionless quotient of the two which explicitly indicates how many times the first number contains the second In mathematics, a ratio is...

• Equidimensional
Equidimensional
Equidimensional is an adjective applied to objects that have nearly the same size or spread in multiple directions. As a mathematical concept, it may be applied to objects that extend across any number of dimensions...

ratios in 3D
• Vertical orientation
Vertical orientation
Vertical orientation is a 3:4 aspect ratio, rotated 90 degrees from an NTSC television's standard 4:3 aspect ratio. It has been used primarily for arcade games and for art projects, including a music video by The Shamen....