The carrying capacity of every aircraft, truck, and ship is ultimately limited by space or weight. If you load a vessel with heavy cargo, you may hit its weight limit before filling all available space. If you load a vessel with light cargo, you may fill all available space before hitting the weight limit.

When calculating the cost of moving your shipment, the carrier will consider both the weight and volume of your cargo, by converting the volume into a “weight equivalent,” also known as volumetric weight (or sometimes dimensional weight). The carrier will then charge per kilogram for whichever is greater: the actual weight (also known as gross weight) or the volumetric weight.

In other words, shipping 1 kilogram of feathers costs more than shipping 1 kilogram of steel, assuming that the cartons of feathers take up more space than the cartons of steel.

This explains why in some cases, especially when shipping by air, you’ll see both actual weight and chargeable weight in your shipment record.

Actual weight is the number you provide us with when you submit your initial quote request. We calculate your quote based on this number. Actual weight = gross weight.

Chargeable weight is the number on your invoice; it’s the amount the carrier charged to move your shipment. The chargeable weight is whichever of the following is greater:

• The gross weight (including the product, packaging, pallet, etc.), or
• The volumetric weight

Terminology:

How is volumetric weight calculated?

Volumetric weight calculations vary by mode of transportation and sometimes by trade lane. This table shows how various types of carriers calculate dimensional weight.

How can I better estimate my shipment’s chargeable weight?

The best way is to make sure that the information you’re providing in your initial quote request is accurate as possible. 

In many cases, we find that once the cargo is picked up, it turns out to be larger than expected. A common reason for this is palletization. Does your supplier palletize your products? This will affect weight and volume. The more you know about how your product is packaged and palletized, the more accurate our quote will be.

Here’s what your actual weight and chargeable weight look like in the Flexport app (actual weight is labeled as total weight):

In addition to appearing on your Flexport invoice, the chargeable weight also appears on the Airway Bill, which you can access in the Documents tab for a given shipment.

Your shipment may be split because the airline will load a combination of lighter and heavier cargo to ensure a safe flight.