widthtoheight

Widthtoheight, commonly written as width-to-height ratio or aspect ratio, denotes the proportional relationship between the width and the height of a rectangle, image, video frame, or display area. It is a dimensionless quantity that describes how wide a shape is relative to its height.

Mathematically, widthtoheight is defined as width divided by height. For example, a 16:9 image has a widthtoheight of 16/9 ≈ 1.78, a 4:3 image has about 1.33, and a square has 1. Ratios can be expressed as colon-separated integers (16:9) or as a decimal.

Practical uses include determining how media should be displayed without distortion, guiding layout and responsive design, and selecting appropriate cropping or letterboxing when resizing. In web design, the CSS aspect-ratio property encodes this ratio to preserve the intended shape across different viewport sizes. In video and photography, common widthtoheight values correspond to standard formats for compatibility and aesthetics.

Because widthtoheight constrains shape but not size, adjusting it can affect composition and framing; preserving the ratio may require padding, cropping, or scaling strategies. Related concepts include pixel aspect ratio and display aspect ratio, both of which distinguish the actual pixel geometry from the overall frame proportion.