The inch (in) is an imperial unit of length equal to exactly 25.4 millimeters, widely used in the United States, Canada, and the United Kingdom. It is the standard measurement for screen sizes, pipe diameters, and mechanical fasteners, and remains common in everyday use across North America. One inch equals exactly 2.54 centimeters.

The foot (ft) is an imperial unit equal to 12 inches or 0.3048 meters, deeply embedded in American construction, aviation altitudes, and everyday measurement. In real estate, room dimensions and property lot sizes are almost always stated in feet across the United States. One foot equals exactly 30.48 centimeters.