The relation of actual weight against volumetrc size gives rise to a volumetric conversion formula that is used by airlines and carriers to ensure correct yield per kilo in relation to space used is applied.
Air Conversion 1 : 5000
Calculation (in cms) : (length x breadth x height) / 5000 = volumetric conversion
Road Conversion 1 : 3000
Calculation (in cms) : (length x breadth x height) / 3000 = volumetric conversion