40x20

40x20 is a size designation used to describe a rectangle with two side lengths of 40 units and 20 units. The units are not inherent in the notation and must be specified in context, which can lead to ambiguity when the source does not state them.

In metric contexts, 40x20 most commonly refers to 40 cm by 20 cm, a dimension frequently used for posters, tiles, picture frames, and wooden boards. It can also denote 40 mm by 20 mm or 0.4 m by 0.2 m in other applications, depending on scale. In imperial contexts, it may indicate 40 inches by 20 inches, though this is less common in standard product labeling.

The area of a 40x20 rectangle is 800 square units (for example, 800 cm² if expressed in centimeters). The perimeter is 2×(40+20) = 120 units. The aspect ratio is 40:20, which simplifies to 2:1.

Because the same notation can refer to different units, it is important to specify the unit when communicating dimensions. In manufacturing and design catalogs, 40x20 is often followed by the unit (for example, 40×20 cm) to avoid misinterpretation.