A simple and easy-to-use distance \ length unit converter. Adding and subtracting Units of Length This app is free of charge. Available unit conversions include: meter (m) gigameter (Gm) megameter (Mm) kilometer (km) hectometer (hm) dekameter (dam) decimeter (dm) centimeters (cm) millimeter (mm) micrometer micron nanometer (nm) yards (yd) foot (ft) inch (in)