Aspect Ratio

This tool works in two modes. Calculate mode takes a ratio (such as 16:9) plus one known dimension (width or height in pixels) and computes the missing dimension. Find Ratio mode takes any width and height in pixels and reduces them to the simplest integer ratio by dividing both by their greatest common divisor. Either mode can be seeded from one of the common preset buttons: 16:9, 4:3, 21:9, 1:1, 3:2, 16:10, 2:3, and 9:16.

1. Choose the Mode radio - Calculate (ratio to dimensions) or Find Ratio (dimensions to ratio). 2. Optionally tap a Common Ratios preset button to fill the inputs. 3. In Calculate mode enter Ratio Width and Ratio Height, pick whether the Known Dimension is width or height, and type its value in px. 4. In Find Ratio mode enter Width and Height in px. 5. Read the result card; use the Copy button to copy the result string (for example 'Width: 1920px, Height: 1080px' or '16:9').

Calculate mode: if width is known, height = round(knownValue * ratioHeight / ratioWidth); if height is known, width = round(knownValue * ratioWidth / ratioHeight). Find Ratio mode: divide both width and height by gcd(width, height) (Euclidean algorithm on the absolute rounded values) to get the simplest whole-number ratio. For example 1920 x 1080 simplifies to 16:9 because gcd(1920, 1080) = 120.