Area is the quantity that expresses the extent of a 2-dimensional object or planar lamina in the plane. Area is measured in any length square units. Most used units are the square kilometer (km²), **square meters** (m²), square miles (mi²), and **square feet** (ft²).

- Square millimeters to square hectometers
- Square centimeters to square decimeters
- Square decimeters to square decameters
- Square decameters to square hectometers
- Square hectometers to square inches
- Square kilometers to square meters
- Square miles to square decameters
- Square yards to square decameters
- Square feet to square miles
- Square inches to square kilometers
- Acres to square millimeters

- Acres
- Square centimeters
- Square decameters
- Square decimeters
- Square feet
- Square hectometers
- Square inches
- Square kilometers
- Square meters
- Square miles
- Square millimeters
- Square yards

- Arpents
- Barns
- Roods
- Square attometers
- Square chains
- Square exameters
- Square femtometers
- Square furlongs
- Square gigameters
- Square megameters
- Square microns
- Square nanometers
- Square petameters
- Square picometer
- Square terameters
- Square yoctometers
- Square yottameters
- Square zeptometers
- Square zettameters