Square millimeters (mm²) to Square inches (in²) Conversion
Square millimeters
The square millimetre is a unit of area equal to one millionth of a square metre (10⁻⁶ m²). In engineering, cross-sectional areas of wires and cables are standardised in square millimetres — electrical cable ratings specify conductor cross-sections in mm² (e.g., 1.5 mm², 2.5 mm², 4 mm²). In materials testing, stress is calculated as force per unit area in megapascals, where the area is expressed in square millimetres.
Square inches
The square inch is a unit of area equal to exactly 6.4516 cm² (the square of 2.54 cm). It is used in engineering for specifying material cross-sections, pressure calculations (pounds per square inch = psi), and the dimensions of small components. Tile and flooring materials in the United States are sometimes measured in square inches for small-format tiles.
| Square millimeters (mm²) | Square inches (in²) |
|---|---|
| 0.1 mm² | 0.00015500031000062 in² |
| 1 mm² | 0.0015500031000062 in² |
| 2 mm² | 0.0031000062000124 in² |
| 3 mm² | 0.0046500093000186 in² |
| 5 mm² | 0.007750015500031 in² |
| 10 mm² | 0.015500031000062 in² |
| 20 mm² | 0.031000062000124 in² |
| 30 mm² | 0.046500093000186 in² |
| 50 mm² | 0.07750015500031 in² |
| 100 mm² | 0.15500031000062 in² |
| 1000 mm² | 1.5500031000062 in² |