The quantification of length, width, height, or volume.

Closely related to scale, measurement is an essential part of communicating design intent, ensuring compliance with clearances, and adhering to code requirements. The ability to quantify an object using a common system of measure has been with humanity since the early measurement systems of Mesopotamia and Egypt, to the development of the Roman pes (or Roman foot), which was imported to England in the mid 1600s. Two main systems of measurement—the imperial system (feet and inches) and the metric system (meters and centimeters, also known as the International System of Units or SI)—are dominant in our contemporary world, and are the basis for measurement in design.

The imperial system was formalized in England in the 1820s with the adoption of the Weights and Measures Act, when all other methods of measurement were repealed. In this system, the units of inch, foot, yard, and mile are used to determine length, with area and volume measurements referred to as squared and cubed respectively.

The metric system of measurement was developed in France after the French Revolution of 1789–99. It is based on the unit of one meter, which was estimated to be one ten-millionth of the distance from the geographic North Pole to the equator, measured over the earth’s surface along a meridian running through Paris, France. The ease of use of metric, which is based on a powers of ten system, has made the International System of Units (or SI) the dominant system of measurement in the world. Length is indicated using the millimeter, centimeter, meter, and kilometer.

Measurement seem intuitive, yet it informs many decisions in the design process both aesthetically and legally. From the mundane (the ideal distance from a chair to a table), to the specific (the width of corridors and doors, or the height of a counter), measurements affect every aspect of an interior.