Dimensional (Volumetric) Weight Explained
Carriers don't just charge for how heavy a parcel is — they also charge for how much space it takes up on the van. That space is measured as dimensional weight (also called volumetric weight), and understanding it is the quickest way to stop overpaying on delivery.
Actual weight vs volumetric weight
Every parcel has two weights. Actual weight is what it reads on the scale. Volumetric weight is a figure derived from its size, standing in for the room it occupies. The carrier bills whichever is greater — so a big, light box is charged as if it were heavy.
The formula
Length × Width × Height (cm) ÷ 5000 = volumetric weight (kg)
The 5000 divisor is the standard used across most European road and parcel networks. Measure the outer dimensions of the packed box, not the product inside.
A worked example
Say you ship a 2 kg order in an oversized 40 × 30 × 30 cm carton:
| Measure | Value |
|---|---|
| Actual weight | 2 kg |
| Volume | 40 × 30 × 30 = 36,000 cm³ |
| Volumetric weight | 36,000 ÷ 5000 = 7.2 kg |
| Billed weight | 7.2 kg (the greater) |
You pay for 7.2 kg to move a 2 kg order. Drop into a snug 25 × 20 × 15 cm box and the volumetric weight falls to 1.5 kg — now the 2 kg actual weight rules, and your cost is set by the real product.
Why a snug box is the biggest lever
Because carriers bill the greater figure, right-sizing the box is usually the single most effective way to cut delivery cost — far more than shaving grams off the contents. A tight box also needs less void fill and protects better. See how to measure a box and our full guide to reducing shipping costs with packaging.
Ready to right-size? Browse our shipping boxes — a range of capacities and dimensions, shipped ex-VAT from Paris via GLS with quantity-break discounts.