Calculation of volumetric weight of goods in international transport: key steps and methodologies
A pallet may weigh 100 kg, yet a freight quotation shows 160 or 192 kg. The difference comes from the dimensions of the packed cargo and the rules of the selected service. Volumetric weight converts occupied space into a weight equivalent, which is then used to establish the shipment’s chargeable weight.
To check a quotation, you need the external dimensions of every package, its actual gross weight, the applicable divisor and the rounding rules. This guide explains the calculations for conventional air freight and express services, works through carton and pallet examples, and shows why a shipment containing several packages sometimes needs a separate calculation for each one.
Actual, volumetric and chargeable weight
Actual gross weight is the weight of the cargo together with its cartons, crates, pallet and other transport packaging. The net weight of the products alone is not the correct figure for this comparison.
Volumetric weight, also called dimensional weight, is a calculated figure in kilograms. It uses the external dimensions of a shipping unit and the conversion factor specified in the tariff. Volume itself is measured in cubic metres or cubic centimetres; neither is a unit of weight.
Chargeable weight is the figure to which a weight-based freight rate is applied. The basic calculation compares actual and volumetric weight and uses the higher figure. If a shipment weighs 120 kg and its volumetric weight is 60 kg, the starting figure for rating is 120 kg. The service’s rounding rules and minimum charges must then be considered.
Measuring cargo before calculating its weight
Measure each shipping unit after it has been fully packed. A pallet’s overall height must include the pallet itself, while its length and width must include any overhang. For an irregular shape, take the outermost points along all three dimensions.
Record the length, width, height, gross weight and quantity of each package size. “Four cartons weighing 80 kg in total” is not enough information if the cartons have different dimensions or weights. State whether they can be stacked or turned onto another side.
Repeat the measurements after cargo consolidation or repacking. A shared pallet adds its own weight, and a protective crate may increase the occupied volume. Measurements taken before packing will not describe the final shipment accurately.
The volumetric weight formula and its units
When all dimensions are in centimetres, use the following formula:
L is length, B is width and H is height, all in centimetres. K is the divisor in cm³/kg. The result, Wvol, is in kilograms. For identical packages, the calculated volume can be multiplied by their quantity; the rules for establishing chargeable weight still need to be checked separately.
If the volume is already expressed in cubic metres, the equivalent calculation is:
This applies to a divisor of 6000, with V in m³ and the result in kg. For a divisor of 5000, the equivalent expression is V / 0.005. One cubic metre contains 1,000,000 cubic centimetres. Do not divide a volume in cm³ by 0.006: that would mix incompatible units.
A divisor of 6000 for conventional air freight
A divisor of 6000 is commonly used for preliminary conventional air freight calculations. It corresponds to approximately 166.67 kg per m³ and appears in DHL Global Forwarding’s calculation guide. Before booking international air freight, confirm the factor in the actual quotation, together with any dimensional or loading restrictions. [1]
A divisor of 5000 for express services
Express services often use a divisor of 5000, equivalent to 200 kg per m³. DHL Express specifies this factor in its guidance. When arranging express delivery of commercial cargo, check the selected service: the word “express” does not establish a universal divisor for every carrier or transport method. [2]
Worked examples for a carton, crate and pallet
The following examples are illustrative. Dimensions and actual weights include packaging; dimensional weights are shown before additional tariff rules are applied.
Shipping unit | Dimensions, cm | Gross, kg | Dimensional kg | Dimensional kg |
|---|---|---|---|---|
Carton | 75 × 50 × 40 | 18 | 25 | 30 |
Crate | 100 × 60 × 60 | 120 | 60 | 72 |
Pallet | 120 × 80 × 100 | 100 | 160 | 192 |
The carton occupies 150,000 cm³, or 0.15 m³. Dividing by 6000 gives 25 kg, while dividing by 5000 gives 30 kg. Both exceed its actual weight of 18 kg, so the basic rating calculation uses the dimensional weight applicable to the service.
The crate’s actual weight of 120 kg exceeds both dimensional results, 60 and 72 kg. Actual weight therefore applies. The fact that the cargo is dense does not justify selecting the lower calculated figure.
The pallet occupies 0.96 m³. Its dimensional weight is 160 kg with a divisor of 6000, or 192 kg with a divisor of 5000. Both exceed the gross weight of 100 kg. However, the difference in chargeable weight alone does not establish which service is cheaper: rates, surcharges and the scope of delivery also need to be compared.
Multiple packages and rounding rules
Calculating each package separately can produce a different result from rating the shipment as a whole. For example, UPS instructs customers to total the billable weights of the individual packages in a multiple-package shipment. [3]
Consider two cartons under a tariff using a divisor of 5000 and a separate comparison for each package. The first measures 50 × 40 × 25 cm, weighs 30 kg and has a dimensional weight of 10 kg. The second measures 50 × 50 × 50 cm, weighs 5 kg and has a dimensional weight of 25 kg. Their combined chargeable weight is 30 + 25 = 55 kg.
Comparing only the total actual weight of 35 kg with the total dimensional weight of 35 kg would understate the result under those rules. Confirm the method of combining package weights before calculating the quotation.
There is also no universal instruction to round to the nearest kilogram. A carrier may require dimensions to be rounded up and apply weight increments such as 0.5 or 1 kg. Check both the increment and the stage at which rounding occurs. FedEx’s published guidance, for example, requires each dimension to be rounded up to the next whole centimetre. [4]
When other transport calculations apply
Do not automatically apply an air freight divisor to international road freight. A road tariff may use weight, cubic volume, pallet positions or occupied floor length. For groupage freight, it is particularly important to declare non-stackable cargo: even a low pallet may prevent the carrier from using the space above it.
Where the tariff is based on occupied floor length, refer to loading metres and LDM calculations. In sea freight, VGM for a packed container means its verified gross mass. It is a separate measurement and cannot be established using the dimensional-weight formula.
Preventing a revised charge after cargo acceptance
Before accepting a quotation, check:
- final packed dimensions and gross weight for every shipping unit;
- the divisor, measurement units and selected service;
- the calculation method for a shipment with multiple packages;
- rounding rules and any minimum charges;
- stackability, overhang and special loading requirements;
- included surcharges and the validity of the quotation.
Reducing unnecessary packaging volume can sometimes lower chargeable weight. For the same 120 × 80 cm pallet, safely reducing its overall height from 100 to 80 cm lowers dimensional weight from 160 to 128 kg at a divisor of 6000. Any saving depends on actual weight and the tariff. The packaging must still provide the protection the cargo needs.
For a quotation from Save Pro Solutions, send the route, cargo description, package list with dimensions and gross weights, cargo-ready date and delivery requirements. Use our guide to the information needed for an international freight quotation to prepare the details. These measurements allow the delivery method to be assessed and the weight used in the quotation to be checked.
