What ratios are supported?

Common ones preset (16:9, 4:3, 21:9, 1:1, golden ratio) plus any custom ratio you type. Math works for any positive pair.

Does it maintain original size?

Two modes: lock width (compute height), or lock height (compute width). For responsive images, the tool shows the CSS `aspect-ratio` property value.

Shows the crop box needed to fit your source into the target ratio. Useful for social-media image guidelines (Instagram 4:5, Twitter 16:9).

Paste multiple dimensions, one per line, get aspect ratios for each. Useful when auditing a large image library for consistency.

Calculate aspect ratios and resize dimensions proportionally. Part of the DevTools Surf developer suite. Browse more tools in the Images collection.

The 16:9 aspect ratio was proposed by Dr. Kerns Powers in 1984 as a mathematical compromise between 4:3 and 2.35:1.
The golden ratio (1.618:1) has been used in art and architecture since ancient Greece and influenced early photography composition.
Instagram originally only supported 1:1 square images until 2015, when it added support for landscape and portrait formats.

What ratios are supported?: Common ones preset (16:9, 4:3, 21:9, 1:1, golden ratio) plus any custom ratio you type. Math works for any positive pair.
Does it maintain original size?: Two modes: lock width (compute height), or lock height (compute width). For responsive images, the tool shows the CSS `aspect-ratio` property value.
What about cropping to a ratio?: Shows the crop box needed to fit your source into the target ratio. Useful for social-media image guidelines (Instagram 4:5, Twitter 16:9).
Can I batch-compute?: Paste multiple dimensions, one per line, get aspect ratios for each. Useful when auditing a large image library for consistency.

Calculate aspect ratios and resize dimensions proportionally. Part of the DevTools Surf developer suite. Browse more tools in the Images collection.

The 16:9 aspect ratio was proposed by Dr. Kerns Powers in 1984 as a mathematical compromise between 4:3 and 2.35:1.
The golden ratio (1.618:1) has been used in art and architecture since ancient Greece and influenced early photography composition.
Instagram originally only supported 1:1 square images until 2015, when it added support for landscape and portrait formats.

What ratios are supported?: Common ones preset (16:9, 4:3, 21:9, 1:1, golden ratio) plus any custom ratio you type. Math works for any positive pair.
Does it maintain original size?: Two modes: lock width (compute height), or lock height (compute width). For responsive images, the tool shows the CSS `aspect-ratio` property value.
What about cropping to a ratio?: Shows the crop box needed to fit your source into the target ratio. Useful for social-media image guidelines (Instagram 4:5, Twitter 16:9).
Can I batch-compute?: Paste multiple dimensions, one per line, get aspect ratios for each. Useful when auditing a large image library for consistency.