Square Miles to Square Kilometers Converter

Area is measured against the square metre, the SI derived unit. Because area is length squared, each metric step is a hundredfold jump, not tenfold: a square metre is 10,000 square centimetres and 1,000,000 square millimetres. The everyday imperial units follow the same rule — a square yard is 9 square feet, and an acre is 43,560 square feet — while land is measured in acres, hectares (10,000 m²), ares and dunams. Traditional South Asian units are widely used for property: a guntha is 1⁄40 of an acre, a cent is 1⁄100 of an acre, and the bigha, katha, marla and kanal are common across India and Pakistan — though several of these vary by region, so this tool uses the most common standard values. East Asian units like the Japanese tsubo, the Korean pyeong and the Thai rai are included too, alongside the scientific barn (10⁻²⁸ m²) used for nuclear cross-sections. Every unit is stored as its exact number of square metres, so any conversion is just the input turned into square metres and then into the target unit.