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Aspect Ratio Calculator

Simplify a width and height into a ratio, or scale dimensions to a target width or height while keeping the ratio.

Leave blank if using target height instead

Leave blank if using target width instead

About the Aspect Ratio Calculator

Simplify a width and height into their aspect ratio, or scale one dimension to match a target width or height.

How to use the Aspect Ratio Calculator

  1. Enter a width and height to see the simplified ratio (e.g. 1920×1080 → 16:9).
  2. Or switch to Scale mode: enter the original width and height, then a target width or height, to calculate the missing dimension while preserving the ratio.
  3. Press Calculate to see the result.

Tips for the Aspect Ratio Calculator

  • 16:9 is the standard widescreen ratio for HD/4K video; 4:3 is the older standard-definition ratio; 1:1 is square (common for social media).

Formula used by the Aspect Ratio Calculator

Simplified ratio = width ÷ GCD(width, height) : height ÷ GCD(width, height)

Example: Aspect Ratio Calculator

Simplifying a 1920×1080 screen resolution

  • Width: 1920
  • Height: 1080

Result: 16:9

The greatest common divisor of 1920 and 1080 is 120, so 1920÷120 : 1080÷120 = 16:9, the standard widescreen ratio.

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