Tutorials

Volumetric Weight: What Is It and How Do You Calculate It?

When you ship a package internationally, you often think about its actual weight. However, some carriers use another metric: volumetric weight. This measurement takes into account the space your package occupies in the airplane, and it may be used instead of the actual weight to determine the shipping cost.

The billable weight depends on the selected carrier: DHL, Chronopost, FedEx and UPS generally apply the volumetric weight, as their services mainly rely on air transportation. In contrast, carriers such as Colissimo or Bpost generally consider the actual weight of the parcel.

1 December 2025
• 4 min

What Is Volumetric Weight?

Volumetric weight represents the amount of space a package takes up in an airplane.
Airlines have limits not only on weight but also on volume.
The cost of shipping is therefore calculated based on the higher value between the actual weight and the volumetric weight.

This means that a lightweight but bulky package can be charged more than a small, dense, and compact one.

How to Calculate Volumetric Weight

Volumetric weight is calculated using the following formula:
Length × Width × Height ÷ carrier divisor

Carriers apply specific rules to calculate volumetric weight. For example, the divisor is 5,000 for FedEx, Chronopost and UPS, and 6,000 for DHL air freight services.

The volumetric weight calculation formulas are as follows:

Dimensions must be expressed in centimetres (cm) and the result in kilograms (kg). In the United States, dimensions are generally expressed in inches.

Concrete example 1: Parcel shipped from Europe with Chronopost

Let’s take two packages with the same actual weight (3 kg) but different dimensions:

Package 1: 40 cm x 25 cm x 30 cm
⇒ Volumetric weight = (40 × 25 × 30) / 5000 = 6 kg
👉 Billing will be based on 6 kg because the volumetric weight exceeds the actual weight.
Package 2: 32 cm x 15 cm x 25 cm
⇒ Volumetric weight = (32 × 15 × 25) / 5000 = 2.4 kg
👉 Billing will be based on 3 kg because the volumetric weight is lower than the actual weight.

In short, 1 kg of lead and 1 kg of feathers are not equal when it comes to volumetric weight:
the lead will always weigh 1 kg, while the feathers, which are bulkier, may be billed for several kilos!

Special case: volumetric weight calculation in inches on our US platform

On our United States platform, an additional rule applies: dimensions are calculated in inches, and each dimension (length, width and height) is rounded up to the next whole unit before the calculation is performed.

However, our systems initially record dimensions in centimetres.

If the formula is applied directly using centimetres without taking the inch rounding rule into account, the volumetric weight will be underestimated compared with the weight charged by the carrier.

To correct this difference, we apply the following conversion process exclusively on our US platform, in accordance with carrier contractual rules:

Conversion from cm → inches
Rounding up each dimension to the next whole inch
Conversion back from inches → cm
Application of the standard contractual divisor (5,000 or 6,000 depending on the carrier). This results in a double unit conversion.

Concrete example 2: Parcel shipped from our US warehouse

Recorded dimensions: 43 × 31 × 18 cm
Actual weight: 1.06 kg

Application of US calculation rules:

43 cm → 16.92 in → 17 in → 43 cm
31 cm → 12.20 in → 13 in → 33 cm
18 cm → 7.08 in → 8 in → 20 cm

Volumetric weight calculation (FedEx – divisor 5,000):

(43 × 33 × 20) ÷ 5,000 = 5.68 kg

The difference between the original dimensions and the dimensions used for the calculation is solely due to the mandatory rounding of dimensions in inches required by US carrier contracts. It is therefore not an arbitrary increase, but the application of the carriers’ calculation rules.

The applied weight (actual or volumetric) is indicated in our price simulator available on our website.

Avoid Unpleasant Surprises with Repacking

At ColisExpat, we know that an oversized box can quickly increase the volumetric weight — and therefore the shipping cost.

That’s why we offer a repacking service to optimize the size of your packages and reduce shipping fees.

The repacking service is available when the total volumetric weight of your parcels exceeds their total actual weight by at least 4 kg, when you select an express carrier (DHL, FedEx, Chronopost or UPS), and when your parcels do not contain sealed and/or fragile products.

👉 Check out our article dedicated to package repacking.