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Calculating Chargeable Weight by Air, Ocean, Road and Rail

Knowing your KG from your CBM


“Whichever is greater” (or “carrier’s choice”) is a phrase to remember when calculating the cost of moving goods by air, ocean, road or rail. That’s because the carrier will always look at two different measurements – the actual weight and the volumetric weight of your shipment – and then base their chargeable weight calculation on the larger figure.

Avoid Underestimation

When freight rates are high it’s particularly important to understand the chargeable weight of your goods whether you are shipping them by air, ocean, road or rail. Shippers who underestimate the chargeable weight are likely to receive an unpleasant surprise when the bill arrives.  Also, knowing the exact chargeable weight along with other factors such as the required transit time helps with selecting the optimal transportation mode.

Two Types of Weight

The carrier compares two different types of weight. The first is the actual, gross, or total physical weight of your shipment, including any packaging and pallets. It is simply the entire shipment weight, typically expressed in kilograms (kgs).

The second type of weight is the volumetric or dimensional weight (the volume of your cargo). It is also expressed in kilograms but based on your shipment’s dimensions (length, width and height in centimetres), to which a density ratio is applied. Do not forget to include all the packages!

Calculating the Volumetric Weight of Your Shipment

The density ratio applied on your shipment depends on the transportation mode you have selected.

Let’s transport the same shipment via all possible modes and find out its volumetric weight! Our shipment consists of two packages, each measuring 120 cm in length, 80 cm in width, and 50 cm in height.

Air Freight: a 1:6 density ratio

  • The formula: ( ( L x W x H, in centimetres ) / 6,000 ) x number of packages( ( 120 x 80 x 50 ) / 6,000 ) x 2 = our shipment has a volumetric weight of 160kg.

Ocean Freight: a 1:1 density ratio

  • The formula: ( ( L x W x H, in centimetres ) / 1,000 ) x number of packages( ( 120 x 80 x 50 ) / 1,000 ) x 2 = our shipment has a volumetric weight of 960kg.
  • This is valid for a less-than-container-load (LCL) shipment; for a full-container-load (FCL) shipment, a per-container charge replaces the volume-based charge.

Rail Freight: a 1:3 density ratio

  • The formula: ( ( L x W x H, in centimetres ) / 3,000 ) x number of packages ( ( 120 x 80 x 50 ) / 3,000 ) x 2 = our shipment has a volumetric weight of 320kg.

Road Freight: a case-by-case scenario

  • Density ratios vary by location and carrier, so check with your intended carriers for full information.

Always Read the Small Print

From time to time, you may find carriers impose different density ratios and this will impact the volumetric weight. If you are familiar with using a 1:3 ratio for inland transportation, for example, but a specific shipment is subject to a 1:2 ratio, the volumetric weight of the same shipment would switch from 333.33 kg to 500 kg.

So What Will My Shipment Cost?

Remember the carrier’s choice and the phrase “whichever is greater,” comparing actual weight and volumetric weight and basing the charge on the higher figure. There is, of course, a clear rationale to this established industry technique – for example, an airplane has both weight restrictions and limited belly space so the carrier must control the weight and the volume of the cargo.

If your cargo contains large machinery parts, it will be heavy but dense. The actual weight will probably be greater than the volumetric weight. And if your cargo contains individual plastic components within protective polystyrene packaging, it will be light but take up a relatively large amount of space. The volumetric weight may be greater than the actual weight.

The chargeable weight of your shipment will always be calculated on whichever is greater: the actual weight or volumetric weight.

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