12inch

12inch, often written 12 in or 12″, is a unit of length in the imperial and United States customary systems. It denotes twelve consecutive inches and is equal to one foot. Since 1959, the international agreement defines the inch as exactly 2.54 centimeters, so 12 inches equals 30.48 centimeters.

Common uses include measuring tools and everyday objects that use inches. A standard 12-inch ruler is 1 foot long. The term also appears in media formats: a 12-inch record has a diameter of 12 inches (about 30 centimeters) and has been used for long-playing albums since the late 1940s. There are also 12-inch singles, which share the same disc diameter but may run at different speeds (commonly 33 1/3 rpm or 45 rpm) and offer extended play tracks.

In modern electronics, screens and devices are often described by diagonal size in inches, and many laptops, tablets, and monitors have a 12-inch class diagonal. The measurement also appears in engineering contexts, where 12-inch denotes the nominal diameter of pipes, fittings, or components in mechanical and construction applications.

Etymology and usage notes: the inch is part of the historical British and American measurement systems and is subdivided into 12 equal parts called lines, and further into smaller fractions for precision. The symbol for inch is the prime mark (in), or a double prime (″) in typographic contexts. The plural form is inches.