The square millimeter (mm²) is a metric unit of area equal to one-millionth of a square meter, used in precision engineering, microelectronics, and medical imaging. It is ideal for measuring the cross-sectional area of wires, the surface area of microchips, and other tiny surfaces. One square millimeter equals roughly 0.00155 square inches.

The hectare (ha) is a metric unit of area equal to 10,000 square meters or 100 ares, widely used in agriculture, forestry, and land management worldwide. Farms, vineyards, and nature reserves are typically described in hectares across Europe, Asia, and Oceania. One hectare equals approximately 2.471 acres, providing a convenient bridge between metric and imperial land measurements.