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Aspect ratio calculator

An aspect ratio is width compared with height, written as two numbers such as 16:9. Enter a ratio and one side to get the other, or enter both sides to reduce them to a ratio. Presets load sizes the platforms publish, such as YouTube's 3840 x 2160 thumbnail and LinkedIn's 1584 x 396 cover image.

Try it

Resolved size

3840 x 2160 (16:9)

How it works

  1. 1

    Pick a preset or type a ratio.

  2. 2

    Enter a width or a height.

  3. 3

    Height = width x (ratio height / ratio width), and the reverse for width.

  4. 4

    Or enter both sides and the tool divides by their greatest common divisor to give the ratio.

Platform facts

FAQ

How do I work out an aspect ratio?
Divide width and height by their greatest common divisor. 1920 x 1080 reduces to 16:9.
Why do some platforms use ratios like 1.91:1?
Some ratios don't reduce to small whole numbers, so platforms write them against 1. 1.91:1 means the width is 1.91 times the height.
Does this resize my image?
It does the math. The size checker pages check a real file.

Optional next step

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Related tools

Also see Schedule posts from Claude

Sources