What is a square unit? Or more precisely, what is 1 square unit? A square unit or 1 square unit is equal to the area of a square having a side length of 1 unit. The figure below shows a square that has an area of 1 square unit.
In the metric system of measurement, some commonly used square units are square centimeter (cm2), square meter (m2), and square kilometer (km2).
In the United States customary system, some commonly used square units are square foot (ft2), square inch (in.2), and square mile (mi2).