When it comes to shipping, couriers take into account not only the weight of the packages but also their volume. It is easy to understand that to move merchandise, its weight (as fuel costs are directly proportional to weight - the more weight, the more energy it takes to move things from point A to point B) is as important as its volume (since the packages you ship occupy a physical space in the vehicles that transport it).

Therefore, as a general rule, couriers calculate the actual weight and the volumetric weight.

Actual weight is the result of directly weighing packages on a scale. It's that simple. This gives us weight in kilograms.

Volumetric weight is the result of applying a formula. This is usually very simple: multiply the measurements of the package (width, height and length), which gives us its volume in m³, and multiply the result with a conversion factor. This factor varies depending on the type of service (shipping via land, air or sea). The conversion factors are usually depending on the courier and the type of service: 167 kg / m³, 200 kg / m³, 250 kg / m³ and 333 kg / m³.

For example, we have a shipment consisting of a single 35x25x20 cm package with a real weight of 1.5 kg. The volume of this package in m³ would be:

Volume = 0.35 x 0.25 x 0.20 = 0.0175 m³.

Thus, depending on the conversion factor that the courier applies to us, the volumetric weight of this package could be 2.92 kg, 3.5 kg, 4.37 kg or 5.82 kg (we have multiplied the volume with different conversion factors described above).

Volumetric weight = Volume x Conversion factor

If the courier applied a factor of 167 kg / m³ for that shipment, the 3 kg rate (resulting 2.92 kg) would be applied instead of the 2 kg rate (which would correspond to the real weight of that shipment - 1.5 kg).

On the contrary, if the real weight of that shipment were 4.8 kg, being greater than 2.92 kg of volumetric weight, the 5 kg rate would be applied to us.

Very easy. For example, if the courier applies a factor of 167 kg / m³, it means that they expect to carry in 1 m³ of space at least 167 kg of cargo.

If you have a shipment that is a cube with a side length of 1 meter (1x1x1 m) and weighs exactly 167 kg (for example 147 litres of water plus 20 kg of the container), it is easy to see that the volumetric weight coincides with the real one: 1 m³ x 167 kg / m³ = 167 kg. Therefore they will charge you the rate for 167 kg. If the container plus the water inside weighs more than 167 kg, for example 200 kg, the 200 kg (real weight) rate would apply.

Now for example, if you ship the same container, but this time it is empty, it still occupies 1 m³ of space and its real weight is only 20 kg. So, in the same space where the courier expected to carry at least 167 kg, it will carry only 20 kg. That is the reason why the volumetric weight would be applied, that is, the rate of 167 kg, regardless of the fact that your container is empty and weighs only 20 kg.

This example applies to any item, be it a shoebox, a coat, or a PC.

It is very important to optimise the packaging of your shipments so that they would occupy the smallest possible volume (of course without compromising the safety of the product). This way you can save quite some money and spend it on the new shipments.