A square foot (sq ft or ft²) is a unit of area commonly used in the United States and some other countries that use the imperial system of measurements. It is defined as the area of a square with sides that each measure one foot (12 inches) in length.
In terms of square meters, one square foot is approximately equal to 0.092903 square meters.
Square feet are frequently used to measure the area of rooms in houses, apartments, and other real estate properties. They are also used for various purposes in construction, architecture, and interior design.
A square mil (abbreviated as sq mil or mil²) is a unit of area measurement used primarily in the United States for very small areas, especially in the context of electrical engineering and wire gauge measurements. One square mil is equal to one square thousandth of an inch or one square mil (0.000001 square inches).
In terms of modern metric units, one square mil is approximately equal to 6.4516 square micrometers (µm²) because there are 25.4 micrometers in one thousandth of an inch (1 mil).
Square mils are often used when specifying the cross-sectional area of wires, particularly in electrical and electronic engineering. For example, the American Wire Gauge (AWG) system uses square mils to represent the cross-sectional area of wires, with smaller wire sizes having fewer square mils, and larger wire sizes having more square mils.