This free conversion calculator converts between common units of length, temperature, area, volume, weight, and time.can realize online conversion between kilometers (km), meters (m), decimeters (dm), centimeters (cm), miles, zhang, chi, cun, fen, li, nautical miles (nmi), fathoms, miles, furlongs (fur), yards (yd), feet (ft), inches (in), millimeters (mm), and micrometers (um).