What Is An Aspect Ratio?

The aspect ratio of an image is the relationship between the width and height.

Generally speaking aspect ratios are express as two numbers with a semi colon between them.

For example a square aspect ratio would be 1:1 whereas classic 35mm film is 3:2.

Here are some common aspect ratios
1.25:1 (5:4)
Early television & large-format computer monitors

1.33:1 (4:3)
Traditional television & computer monitor standard

1.375:1
Academy standard film aspect ratio

1.41:1
√2:1 ~1.4142:1, ISO 216 paper sizes (A4)

1.43:1
IMAX motion picture film format

1.5:1 (3:2)
Classic 35 mm still photographic film

1.6:1 (8:5) (aka 16:10)
A common computer screen ratio.

1.6180:1 (16.18:10)
The golden ratio

1.6667:1 (5:3)
A common European widescreen std.; Native Super 16 mm film.

1.77:1 or 1.78:1 (16:9)
HD video std.; U.S. digital broadcast TV std.

1.85:1
A common US widescreen cinema standard

2.39:1
A current widescreen cinema standard

Here are some common sensor sizes:
digital camera sensor size comparison

See also: