Square kilometre (U.S. spelling: square kilometer), symbol km2, is a decimal multiple of the SI unit of surface area, the square metre, one of the SI derived units. 1 km2 is equal to: * 1,000,000 m2 * 100 ha (hectare) * 0.386102 square miles * 247.105381 acres Conversely: * 1 m2 = 0.000 001 (10−6) km2 * 1 hectare = 0.01 (10−2) km2 * 1 square mile = 2.589988km2 * 1 acre = 0.004047km2, 0.4047ha or 4047 m2