The volumetric weight of a shipment is a calculation that reflects the density of a package. A less dense item generally occupies more volume of space, in comparison to its actual weight. The volumetric or dimensional or,
cubed or DIM weight is calculated and compared with the actual weight of the shipment to ascertain which is greater; the higher weight is used to calculate the shipment cost.
For Freight / Cargo :
The formula for calculating volumetric weight is length x width x height (cm) / 6000
For Courier :
The formula for calculating volumetric weight is length x width x height (cm) / 5000
Volume weight, if a box has a limit of 30 kg and you put only 10-12kg in that box than airline will charge 30kg, not 10-12kg. While sending duvets, pillows, soft toys & so on which take more space than actual weight. The best way to reduce volume weight of your shipment is to buy vacuum bags, put everything which is not fragile as duvet and pillows etc. in bag suck whole air with a vacuum cleaner and seal it after that pack it in box or suitcases. Please do not try this procedure on Fragile, sentiments or Extra value items.