Square Inch [in2] to Square Kilometer [km2] Converter

Definition: A square inch (in²) is a unit of area equal to the area of a square that is 1 inch on each side. It is commonly used in the United States and other countries that use the imperial system.

History/origin: The square inch is derived from the inch, which has ancient origins and was traditionally based on the width of a human thumb. Its exact definition has varied throughout history.

Current use: Square inches are used to measure smaller areas, such as the surface area of objects, screens, or printed materials. It's a common unit in manufacturing, design, and everyday measurements in the US.

Definition: A square kilometer (km²) is a unit of area equal to a square that is 1 kilometer on each side. It is a multiple of the square meter, the SI unit of area.

History/origin: The square kilometer is derived from the kilometer, which is part of the metric system established in France in the late 18th century. The metric system was designed to be a standardized and coherent system of measurement based on decimal multiples.

Current use: Square kilometers are used to measure large areas, such as the size of cities, countries, lakes, and other geographical features. It's a common unit in geography, cartography, and environmental studies.