Architectural scale/Engineering scale

A measurement device used to show how to measure scaled dimensions on scale drawings. When using the Metric system, the paired ratio is millimeters (mm) to meters (m) or centimeters (cm) to meters (m). When using the English measurement system, the paired ratio is in the form of fractions of inches (1/2, 1/4, 1/8th inch or 10th, 20th, or 30th of an inch) being equal to a foot.