# Aspect ratio (image)

**Aspect ratio (image)** is the ratio of the width to the height of a film frame, image, or screen, written X:Y as in 4:3 or 16:9, and it determines how an image appears on screen based on how it was shot.<sup>[1](https://filmglossary.ccnmtl.columbia.edu/term/aspect-ratio/)</sup> The purpose of fixing a defined ratio is practical: cameras and display equipment are matched so that when a film is shot it can be shown without inconvenient cropping or distortion.<sup>[2](https://www.oxfordreference.com/display/10.1093/acref/9780198832096.001.0001/acref-9780198832096-e-0038)</sup>

| Key fact | Detail |
|---|---|
| Definition | Ratio of picture width to picture height, notated X:Y; also called display aspect ratio (DAR)<sup>[3](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)</sup> |
| Silent and early sound film | Silent full-frame films commonly displayed at 4:3 (1.33:1); the Academy ratio of 1.37:1 adopted in 1932 for Hollywood sound films<sup>[4](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)</sup> |
| Theatrical standards | US and UK widescreen standard for 35mm film is 1.85:1; the anamorphic print standard is 2.35:1 with 2:1 compression<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup><sup> • </sup><sup>[6](https://doi.org/10.5594/j05734)</sup> |
| Television and HD | Widescreen television is 16:9 (1.78:1), at 1920:1080 pixels or 3840:2160 in 4K<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup><sup> • </sup><sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup> |
| Anamorphic method | An anamorphic lens squeezes a wide image onto a 35mm frame; a similar lens at projection restores it, with horizontal dimensions twice the vertical<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup> |
| Fitting mismatched ratios | Letterboxing for widescreen on 4:3, pillarboxing for the reverse, pan-and-scan cropping, and stretching as distortion<sup>[3](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)</sup> |
| Vertical formats | A square 1:1 ratio is used on Instagram; a vertical 9:16 ratio has gained acceptance for phone viewing<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup> |

## Definition and notation

Picture aspect ratio is notated X:Y, where X:Y is the ratio of picture width to picture height.<sup>[3](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)</sup> In video engineering the same quantity is called the display aspect ratio (DAR), and it relates to the stored pixels through DAR = (image width in pixels / image height in pixels) × PAR, where PAR is the pixel aspect ratio; this distinction matters because stored pixels are not always square.<sup>[3](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)</sup>

Ratios are written as reduced integers (16:9) or as decimals (1.78:1) interchangeably: 16:9 equals 1.78:1, and 4:3 equals 1.33:1. Most video standards use either 4:3 or 16:9, with 16:9 commonly called widescreen; cinema film often uses 1.85:1 or 1.66:1.<sup>[3](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)</sup>

## History: from Academy ratio to widescreen

Most silent film used a 1.33:1 aspect ratio; if a screen was ten feet high it would be 13.3 feet wide.<sup>[2](https://www.oxfordreference.com/display/10.1093/acref/9780198832096.001.0001/acref-9780198832096-e-0038)</sup> In 1932 a slightly wider frame, 1.37:1, was adopted for Hollywood sound films because it added room for an audio track at the edge of the frame, and it became known as the Academy Ratio.<sup>[4](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)</sup><sup> • </sup><sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup> The sources differ on which body set it: the US National Archives attributes the 1932 adoption to the Society of Motion Picture Engineers,<sup>[4](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)</sup> while the Columbia Film Language Glossary says the [Academy of Motion Picture Arts and Sciences](https://www.edgepedia.org/academy-of-motion-picture-arts-and-sciences) dubbed the 1.33:1 "Academy aperture" in 1932 and that this became the first standard film ratio, used until the 1950s.<sup>[1](https://filmglossary.ccnmtl.columbia.edu/term/aspect-ratio/)</sup>

Once television arrived in the 1950s, the film industry faced a new rival and started adopting broader screen ratios.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup> Hollywood studios began experimenting with fitting wider images onto 35mm film, and the new widescreen productions gave audiences a viewing experience much more expansive than that of their television screens.<sup>[4](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)</sup>

## Motion picture film formats and anamorphic photography

**Anamorphic squeeze.** [CinemaScope](https://www.edgepedia.org/cinemascope) uses an anamorphic camera lens to squeeze the image into the available space on a 35mm frame; when projected, a similar lens displays an undistorted image in which the horizontal dimensions are twice the vertical.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup> The National Archives describes the same process from the recording side: CinemaScope squeezed a widescreen image of up to 2.66:1 onto film that typically held a 1.37:1 unsqueezed image.<sup>[4](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)</sup> The two descriptions differ in the degree of squeeze they emphasize, a 2:1 compression at projection versus an up-to-2.66:1 source image on a 1.37:1 frame, and the sources do not reconcile them.

A SMPTE standard specifies the maximum dimensions of the film image area intended for projection from a 35mm anamorphic motion-picture print with a compression ratio of 2:1 and an aspect ratio of 2.35:1, including the placement of this area relative to the perforations and the reference edge of the film.<sup>[6](https://doi.org/10.5594/j05734)</sup> CinemaScope is written 2.35:1 or 2.39:1.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup>

**The 1950s wide processes.** The widescreen era produced a family of ratios: 2.59 (Cinerama), 2.35 (CinemaScope), 2.2 (Todd-AO), 2.76 (MGM 65), and 2.20 (Super [Panavision](https://www.edgepedia.org/panavision)), used for epics like *Patton*, *Ben-Hur*, and *Lawrence of Arabia*.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup> The US and UK widescreen standard for 35mm film settled at 1.85:1, and the standard for Hollywood theatrical releases remains 1.85:1, spanning from the nearly square television ratio of 1.33:1 to very long rectangles.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup><sup> • </sup><sup>[8](https://static.brooklyn.edu/web/Film_Glossary_2015(1).pdf)</sup>

## Television and digital video

Early television systems used 5:4 to provide the maximum rectangle obtainable on the circular picture tubes then in use; 4:3 became the standard television aspect ratio, and widescreen television is 16:9.<sup>[9](https://web.archive.org/web/20211126170702/https:/www.nfsa.gov.au/preservation/preservation-glossary/aspect-ratio)</sup>

[High-definition television](https://www.edgepedia.org/high-definition-television), developed in the 1990s, settled on 1.78 (16:9) as a middle ground between 1.33 and 2.59. This ratio remains the standard for YouTube and Vimeo content, at 1920:1080 pixels, or 3840:2160 in 4K resolution.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup>

## How it compares with sibling formats

The common ratios form a spectrum from nearly square to extremely wide:

- **4:3 (1.33:1)**, the silent-film and standard-television rectangle.<sup>[4](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)</sup>
- **16:9 (1.78:1)**, the widescreen and high-definition television standard.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup>
- **1.85:1**, the US and UK theatrical standard for 35mm film.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup>
- **2.35:1 / 2.39:1**, the anamorphic CinemaScope lineage.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup>
- **2.76:1**, the MGM 65 process, the widest of the 1950s systems listed.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup>
- **9:16**, the vertical phone format, the same rectangle as 16:9 rotated.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup>

There is no single preferred cinematographic ratio: research presented at an SMPTE technical conference found no clear indication of a preference for any particular aspect ratio, and showed that cinematographers have not always favored a single one.<sup>[10](https://journal.smpte.org/conferences/Proceedings%20137th%20SMPTE%20Technical%20Conference%20and%20World%20Media%20Expo/40/)</sup> Directors sometimes use several ratios within one film; [Wes Anderson](https://www.edgepedia.org/wes-anderson)'s *The Grand Budapest Hotel* used the Academy Ratio for its 1930s scenes, 2.35 for 1960s action, and 1.85 for its present-day 1980s action.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup>

## Transferring between ratios

When image and display shapes do not match, four outcomes are possible. Scaling a widescreen image to fit a 4:3 display is called letterboxing, with bars typically filled with black; the reverse, scaling a 4:3 image to fit a widescreen display, is sometimes called pillarboxing. Pan-and-scan is a technique whereby a widescreen image is cropped to a 4×3 rectangular area that can shift frame to frame for display on a 4:3 device. Nearly always incorrect is the practice of stretching an image so that it fits the display area, since this fails to keep the picture aspect ratio correct.<sup>[3](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)</sup>

The reference point in these conversions is the original aspect ratio (OAR), the aspect ratio in which the filmmaker intended the film to be viewed.<sup>[5](https://aso.gov.au/about/aspect-ratio/)</sup>

## By the numbers

- **1920:1080** and **3840:2160** are the pixel dimensions of 16:9 content at HD and 4K respectively.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup>
- **2:1** is the anamorphic compression ratio of the 35mm print standard, which specifies a projected aspect ratio of 2.35:1.<sup>[6](https://doi.org/10.5594/j05734)</sup>
- **1.85:1** is the standard for Hollywood theatrical releases.<sup>[8](https://static.brooklyn.edu/web/Film_Glossary_2015(1).pdf)</sup>
- **1:1** is Instagram's standard, and **9:16** is the accepted vertical ratio for phone viewing, a format with enough practitioners that a biennial Vertical Film Festival was created in Australia.<sup>[7](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)</sup>

## References

1. [Aspect Ratio, Columbia Film Language Glossary](https://filmglossary.ccnmtl.columbia.edu/term/aspect-ratio/)
2. [Aspect ratio, A Dictionary of Film Studies, Oxford Reference](https://www.oxfordreference.com/display/10.1093/acref/9780198832096.001.0001/acref-9780198832096-e-0038)
3. [Picture Aspect Ratio, Microsoft Learn](https://learn.microsoft.com/en-us/windows/win32/medfound/picture-aspect-ratio)
4. [The Measure of a Screen: Motion Picture Aspect Ratios in the Archives, The Unwritten Record (US National Archives)](https://unwritten-record.blogs.archives.gov/2018/01/18/the-measure-of-a-screen-motion-picture-aspect-ratios-in-the-archives/)
5. [Aspect ratio on ASO, Australia's audio and visual heritage online](https://aso.gov.au/about/aspect-ratio/)
6. [SMPTE standard for 35mm anamorphic motion-picture prints (2:1 compression, 2.35:1)](https://doi.org/10.5594/j05734)
7. [The importance of aspect ratio in modern filmmaking, Adobe](https://www.adobe.com/creativecloud/video/discover/aspect-ratio.html)
8. [Brooklyn College Film Glossary](https://static.brooklyn.edu/web/Film_Glossary_2015(1).pdf)
9. [Aspect ratio, National Film and Sound Archive of Australia (archived)](https://web.archive.org/web/20211126170702/https:/www.nfsa.gov.au/preservation/preservation-glossary/aspect-ratio)
10. [The History of the Perfect Aspect Ratio, 137th SMPTE Technical Conference proceedings](https://journal.smpte.org/conferences/Proceedings%20137th%20SMPTE%20Technical%20Conference%20and%20World%20Media%20Expo/40/)

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*Topic: Encyclopedia › Arts and culture › Screen and stage › Film and television › Films and standalone screen works › Film industry, institutions, festivals, and awards › Exhibition, venues, and film technology › Motion picture film formats*

*Initially written Sep 17, 2026 · Reviewed: Sep 30, 2026; Oct 25, 2026 · Edited: Sep 30, 2026; Oct 25, 2026 · Last review: Oct 25, 2026*

*Copyright 2026 EdgeChat AI, a subsidiary of Biostate AI.*

License: Edgepedia Community License 1.0, https://www.edgepedia.org/edgepedia/license