°API 141.5/(131.5+°API) = gm/cm3 °F (°F-32)/1.8 = °C acre x 4.046 856 E -01 = ha ft x 3.048* E -01 = m md x 9.869 233 E -04 = µm2 mile x 1.609 344* E+00 = km psi x 6.894 757 E+00 = kPa