Inch

Definition: An inch (symbol: in) is a unit of length in the imperial and United States customary systems of measurement. An inch was defined to be equivalent to exactly 25.4 millimeters in 1959. There are 12 inches in a foot and 36 inches in a yard.

History/origin: The term "inch" was derived from the Latin unit "uncia" which equated to "one-twelfth" of a Roman foot. There have been a number of different standards for the inch in the past, with the current definition being based on the international yard. One of the earliest definitions of the inch was based on barleycorns, where an inch was equal to the length of three grains of dry, round barley placed end-to-end. Another version of the inch is also believed to have been derived from the width of a human thumb, where the length was obtained from averaging the width of three thumbs: a small, a medium, and a large one.

Current use: The inch is mostly used in the United States, Canada, and the United Kingdom. It is also sometimes used in Japan (as well as other countries) in relation to electronic parts, like the size of display screens. In the United States, the inch is widely used in everyday applications such as measuring dimensions of products, screen sizes, paper sizes, and small distances. Inches are commonly used in construction, carpentry, and manufacturing industries.

Foot

Definition: A foot (symbol: ft) is a unit of length in the imperial and US customary systems of measurement. A foot was defined as exactly 0.3048 meters in 1959. One foot contains 12 inches, and one yard is comprised of three feet.

History/origin: Prior to standardization of units of measurement, and the definition of the foot currently in use, the measurement of the foot was based on the length of the human foot. Since the human foot commonly varies in length from about 9.5 inches to 11.5 inches, there were naturally regional variations in what constituted a foot. Due to these variations, it was eventually decided upon internationally that a foot should be defined as exactly 0.3048 meters, leading to the current definition.

Current use: The foot is primarily used in the United States, Canada, and the United Kingdom for many everyday applications. In the US, feet and inches are commonly used to measure height, shorter distances, field length (sometimes in the form of yards), room dimensions, and ceiling heights. Feet are also commonly used to measure altitude (aviation) as well as elevation (such as that of a mountain). The foot remains one of the most common units for everyday measurements in countries using the imperial system.

Inch to Foot Conversion Table

How to Convert Inch to Foot