What is W/M (Weight Measurement) and how does it work?

What is air cargo settlement based on W/M (Weight/Measurement)?
When sending air cargo shipments, settlement is often based on the W/M method, which stands for Weight/Measurement (weight/volume). This means that shipping charges are calculated based on the actual weight of the shipment (in kilograms) or the volume weight, whichever is higher. This system ensures that both heavy and bulky goods are charged fairly.

How does tariff calculation based on Weight/Measurement work?
Airlines and freight forwarders use a standard formula to calculate the volume weight of a shipment. This goes as follows:

1. Determine the actual weight of the shipment in kilograms.
2. Calculate the volume weight using the following formula: length x width x height/6000. In some cases, a different division factor may be used, such as 5000 or 7000, depending on the airline or type of cargo.
3. Compare the actual weight and the volume weight. The higher value is used as the taxable weight for the freight cost calculation.

Why is W/M used?
The use of W/M prevents inefficient use of airline capacity. For example, a large but light shipment takes up a lot of space, while a small but heavy shipment requires less space. By applying W/M, rates are distributed fairly based on a shipment's impact on available cargo space.

Practical example
Suppose you have a shipment with the following dimensions:

• Length: 100 cm
• Width: 50 cm
• Height: 40 cm
• Actual weight: 20 kg

The volume weight is then calculated as 33.3 kgs. Since the volume weight (33.3 kg) is higher than the actual weight (20 kg), the volume weight is used as the dutiable weight for the rate calculation.

With air freight offices in Amsterdam and Brussels, Rotra has a global network with locally specialized agents. In addition to attractive pricing, we ship ship shipments end-to-end under our own management where we also provide pre- and on-carriage. Would you like further information from one of our air freight specialists? For more info contact us directly.