Each means of conveyance, such as container vessel, truck or aircraft, has a limited space.(volume constraint) Additionally there are weight limitations for all types of modes of transport. (weight constraint)
In order to sell their free spaces more efficiently, international logistics sector developed a concept, which is known as chargeable weight.
According to this concept, first of all transport companies are calculating an hypothetical volumetric weight of the cargo to compare it with the actual gross weight of the goods.
Then, they choose the bigger amount, either actual gross weight or hypothetical volumetric weight. Result is known as the chargeable weight.
Only chargeable weight is used by international logistics companies, when calculating their freight offers.
Why transport companies do not use gross weight or volume of the cargo but chargeable weight when calculating freight costs?
Some goods are heavy, but take very limited space; whereas others are really light but allocates tons of room in the transport vehicle.
As an example you can compare marble and fiberglass insulation.
Marble is dead heavy as 1 cubic metre of marble weights around 2500kgs. You can reach the gross weight limit of a 40ft dry container by loading around 9 cubic meters of marble.
Loading efficiency in terms of volume: 9 cbm marble volume/ 67cbm 40ft container volume=13%
Fiberglass insulation is one of the lightest commodity on the market as 1 cubic metre of fiberglass insulation weights around 80kgs. You can fill the 40ft dry container by loading around 5360 kgs of fiberglass insulation.
Loading efficiency in terms of weight: 5360 kgs fiberglass insulation weight / 22000 kgs loading limit for 40ft container = 24%
As it is demonstrated on the above example, using either weight or volume as a price determinant for the freight costs would lead to ineffectiveness for the transport companies.
How to calculate chargeable weight in air shipments?
In order to determine chargeable weight in air shipments, first of all you have to calculate the volumetric weight.
As an example you can compare marble and fiberglass insulation. Marble is dead heavy as 1 cubic metre of marble weights around 2500kgs. You can reach the gross weight limit of a 40ft dry container by loading around 9 cubic meters of marble.
Loading efficiency in terms of volume: 9 cbm marble volume/ 67cbm 40ft container volume=13%
Fiberglass insulation is one of the lightest commodity on the market as 1 cubic metre of fiberglass insulation weights around 80kgs. You can fill the 40ft dry container by loading around 5360 kgs of fiberglass insulation.
Loading efficiency in terms of weight: 5360 kgs fiberglass insulation weight / 22000 kgs loading limit for 40ft container = 24%
As it is demonstrated on the above example, using either weight or volume as a price determinant for the freight costs would lead to ineffectiveness for the transport companies.
Let me explain you below step by step calculation process of both volumetric weight and chargeable weight in air shipments based on the following example:
Let us assume that we want to ship a cargo consists of 10 packages with the measurements below:
- Dimensions of each package: 100cmx90cmx80cm
- Weight of each package: 100kgs/gross weight
Step1 : Calculating the gross weight of the cargo: In order to make a comparison with the calculated volumetric weight you should know the gross weight of the cargo.
The gross weight of our cargo is 1000kgs.
Step2 : Calculating the volume of the cargo: In order to reach the volumetric weight, you should calculate the volume of the cargo in cubic meters.
- Dimensions of one package in centimetre => 100cm x 90cm x 80 cm
- Dimensions of one package in metre => 1m x 0,9m x 0,8m
- Volume of one package = 1m x 0,9m x 0,8m = 0,72 cbm (cubic metre)
- Total volume of the cargo = 10 x 0,72 cbm = 7,2 cbm
Step3 : Calculating the volumetric weight of the cargo: You should multiply the volume of the cargo with air shipment volumetric weight constant, in order to reach the volumetric weight.
Air shipment volumetric weight constant = 167 kgs / cbm
Volumetric Weight= Total volume of the cargo x air shipment volumetric weight constant
Volumetric Weight= 7,2 cbm x 167 kgs/ cbm = 1202,4 kgs
Step4 : Calculating the chargeable weight of the cargo: You should compare the gross weight of the cargo with the volumetric weight of the cargo and select the biggest amount. This will be your chargeable weight for the given air shipment.
- Gross weight of our cargo is 1000kgs.
- Volumetric Weight of our cargo is 1202,4 kgs
- Volumetric weight is higher than the actual gross weight so we have to use volumetric weight as our chargeable weight, which is 1202,4 kgs.
How to calculate chargeable weight in sea shipments?
We have to follow the same steps when calculating the chargeable weight in sea shipments with only one exception: Sea shipment volumetric weight constant is different than air shipment volumetric weight constant.
You should take sea shipment volumetric weight constant as 1000 kgs / cbm, when calculating the chargeable weight in sea shipments.
Let me explain you below step by step calculation process of both volumetric weight and chargeable weight in sea shipments based on the following example:
Let us assume that we want to ship a cargo consists of 10 packages with the measurements below:
- Dimensions of each package: 120cmx100cmx150cm
- Weight of each package: 800kgs/gross weight
Step1 : Calculating the gross weight of the cargo: The gross weight of our cargo is 8000kgs.
Step2 : Calculating the volume of the cargo:
- Dimensions of one package in centimetre => 120cmx100cmx150cm
- Dimensions of one package in metre => 1,2m x 1m x 1,5m
- Volume of one package = 1,2m x 1m x 1,5m = 1,8 cbm (cubic metre)
- Total volume of the cargo = 10 x 1,8 cbm = 18 cbm
Sea shipment volumetric weight constant = 1000 kgs / cbm
Volumetric Weight= Total volume of the cargo x sea shipment volumetric weight constant
Volumetric Weight= 18 cbm x 1000 kgs/ cbm = 18000 kgs
Step4 : Calculating the chargeable weight of the cargo: You should compare the gross weight of the cargo with the volumetric weight of the cargo and select the biggest amount. This will be your chargeable weight for the given sea shipment.
- Gross weight of our cargo is 8000kgs.
- Volumetric weight of our cargo is 18000 kgs
- Volumetric weight is higher than the actual gross weight so we have to use volumetric weight as our chargeable weight, which is 18000 kgs.
How to calculate chargeable weight in road shipments?
Road shipment volumetric weight constant is different than both air and sea shipment volumetric weight constants. Other than that all steps are the same for calculating chargeable weight.
You should take road shipment volumetric weight constant as 300 kgs / cbm, when calculating the chargeable weight in road shipments.
Let me explain you below step by step calculation process of both volumetric weight and chargeable weight in road shipments based on the following example:
Let us assume that we want to ship a cargo consists of 10 packages with the measurements below:
- Dimensions of each package: 120cmx100cmx180cm
- Weight of each package: 960kgs/gross weight
Step1 : Calculating the gross weight of the cargo: The gross weight of our cargo is 9600kgs.
Step2 : Calculating the volume of the cargo:
Volumetric Weight= Total volume of the cargo x road shipment volumetric weight constant
- Dimensions of one package in centimetre => 120cmx100cmx180cm
- Dimensions of one package in metre => 1,2m x 1m x 1,8m
- Volume of one package = 1,2m x 1m x 1,8m = 2,16 cbm (cubic metre)
- Total volume of the cargo = 10 x 2,16 cbm = 21,6 cbm
Road shipment volumetric weight constant = 333 kgs / cbm
Volumetric Weight= Total volume of the cargo x road shipment volumetric weight constant
Volumetric Weight= 21,6 cbm x 333 kgs/ cbm = 7192,8 kgs
Step4 : Calculating the chargeable weight of the cargo: You should compare the gross weight of the cargo with the volumetric weight of the cargo and select the biggest amount. This will be your chargeable weight for the given road shipment.
- Gross weight of our cargo is 9600kgs.
- Volumetric weight of our cargo is 7192,8 kgs
- Gross weight is higher than the volumetric weight so we have to use actual gross weight as our chargeable weight, which is 7192,8 kgs.
