Gross weight includes everything that travels as cargo: the product, its packaging, cardboard, film and pallet. It excludes the tare of the container or vehicle. It is the weight on the consignment note and the one compared with volumetric weight to get the chargeable weight.
It is also the basis of the carrier’s liability: the CMR limits compensation to 8.33 SDR per kilo of gross weight short (art. 23). A misdeclared gross weight therefore changes not only the invoice but also what you can claim.