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.
A square meter (symbol: m²) is a unit of area in the International System of Units (SI), which is the metric system commonly used in many countries worldwide. It is defined as the area of a square with sides that each measure one meter in length.
To give you a visual sense of the size of a square meter, imagine a square that is one meter long on each side. It is equal to 10,000 square centimeters (cm²) or 0.0001 hectares (ha). In square feet, one square meter is approximately 10.7639 square feet (sq ft).
The square meter is the primary unit for measuring area in the metric system and is widely used in various scientific, engineering, and everyday applications for describing land area, room dimensions, and many other surface measurements.