Why your packing list, your VGM and your freight bill show three different weights
Somebody compares the packing list to the VGM to the carrier's invoice, finds three different figures, and asks which is right. All of them are. They measure different things, and the confusion causes real problems — amended documents that did not need amending, and queries at destination about discrepancies that are not discrepancies.
Net weight
The goods alone. No packaging, no pallet.
This is what your customer bought and what customs usually assesses against for anything charged by weight. It appears per line on the packing list and, for some commodities, on the commercial invoice.
Net is always lower than gross. If the two are equal on your packing list, somebody has typed one figure into both columns.
Gross weight
Goods plus packaging plus pallet. What has to be lifted.
Gross appears on the packing list, on the bill of lading, and on almost every transport document. It is the number a destination broker reconciles across the set, so it must be identical everywhere it appears.
The difference between net and gross is the tare — the packaging by itself. Worth stating separately where the packing is heavy, because a steel frame or a timber crate can explain a gross weight that otherwise looks wrong for the goods declared.
Verified gross mass
The gross weight of a packed container, including the container's own tare. Certified under SOLAS by the shipper named on the bill of lading, and a condition of the box being loaded at all.
So the VGM is legitimately higher than the gross weight on your packing list: it includes several tonnes of steel container that your cargo documents never mention. A twenty-foot box is roughly 2,200 kg empty and a forty-foot around 3,800 kg.
Two ways to arrive at it. Weigh the packed container. Or weigh the cargo and add the container tare from the plate on the door. Either is acceptable; what is not acceptable is estimating.
Chargeable weight
What the carrier bills you on, and it is not a weight at all — it is whichever is greater of actual weight and volumetric weight.
Volumetric weight converts space into a weight-equivalent using a divisor set by mode: air freight commonly 6,000 cm³ per kg, sea LCL typically treating one cubic metre as one tonne. Ship a pallet of cushions and you pay for the space; ship a pallet of bolts and you pay for the mass.
This number appears on the freight invoice and nowhere else, which is why it looks like an error to anyone reconciling documents. It should not appear on the packing list or the bill of lading.
Getting them to agree, where they should
Three rules cover it.
Gross weight is identical everywhere it appears. Packing list, bill of lading, certificate of origin if it carries one.
VGM is higher than gross, by roughly the container tare. If it is not, either the tare was forgotten or the cargo weight was.
Chargeable weight sits only on the freight invoice. If it has migrated onto a shipping document, someone has copied the wrong figure, and that is a discrepancy a broker will stop on.