Chargeable weight is the weight a carrier bills for, and it is the greater of a shipment’s actual weight and its volumetric weight. Volumetric weight converts the space the cargo occupies into a weight equivalent. Bulky, light cartons are therefore charged by the room they take, while dense cargo is charged by what it weighs.
How is chargeable weight calculated?
Calculate actual weight and volumetric weight separately, then take the larger. The formulas match the CBM and chargeable weight calculator.
- Volume (m³) = length x width x height of one carton (in cm) / 1,000,000 x number of cartons
- Volumetric weight (kg) = length x width x height of one carton (in cm) / divisor x number of cartons
- Chargeable weight = the greater of actual weight and volumetric weight
The divisor, in cubic centimetres per kilogram, depends on the mode and the carrier. Air cargo commonly uses 6,000 and many express couriers use 5,000. For sea freight the usual rule is that one cubic metre counts as 1,000 kg, and road freight often uses about 300 kg per cubic metre. These are common conventions, not universal rules, so confirm the divisor in your carrier’s quote or terms.
Worked example: before and after repacking
The numbers are illustrative. A shipment has 10 cartons measuring 50 x 40 x 30 cm, with a total gross weight of 90 kg, going by air with a divisor of 6,000.
- One carton = 50 x 40 x 30 = 60,000 cm³.
- Volume = 60,000 / 1,000,000 x 10 = 0.6 m³.
- Volumetric weight = 60,000 / 6,000 x 10 = 100 kg.
- Chargeable weight = greater of 90 kg and 100 kg = 100 kg, billed on volume.
Now suppose the cartons are redesigned to 50 x 40 x 25 cm with the same contents. Each carton is 50,000 cm³, so volumetric weight = 50,000 / 6,000 x 10 = about 83.3 kg. That is below the 90 kg actual weight, so the chargeable weight becomes 90 kg. A 5 cm change in height removed about 10 percent from the billed weight. With an express divisor of 5,000, the original cartons would be 120 kg, which shows why the divisor matters as much as the dimensions.
Which weight do you pay for?
You pay for whichever number is higher. If volumetric weight exceeds actual weight, the cargo is “light and bulky” and you are paying for space. If actual weight is higher, the cargo is dense and you are paying for weight.
| Situation | What is billed | What to do |
|---|---|---|
| Volumetric weight above actual weight | Volumetric weight | Shrink cartons, remove void space, consider nesting or flat-packing |
| Actual weight above volumetric weight | Actual weight | Reduce product or packaging weight; extra volume is free up to the point of balance |
| Both close together | Either; small changes flip the result | Check both numbers on each quote |
What do carriers actually measure?
Carriers measure the outer dimensions of the cargo as tendered, and many round each dimension up and apply the divisor to the total shipment rather than each carton. Pallets, overhang and loose items affect the measurement. Some carriers also apply minimum charges and break points, where the rate per kilogram drops once the chargeable weight passes a threshold. Ask for the carrier’s measuring rules and check whether rounding is applied per piece or per shipment, because it changes the result.
Common mistakes
- Using net product weight instead of gross weight with packaging.
- Assuming one divisor applies to every carrier and mode.
- Measuring the inside dimensions of a carton instead of the outside.
- Forgetting that mixed carton sizes need each size calculated, then summed.
- Ignoring pallet height and overhang when cargo is palletised.
- Comparing quotes per kilogram without checking whether the weight basis is actual or chargeable.
- Redesigning packaging for lower chargeable weight without checking protection.
How packaging choices change the bill
Packaging is the main lever because it changes volume without changing the product. Right-sized cartons, removing void fill, flat-packing, nesting stackable items and shipping goods unassembled all reduce volumetric weight. Check each change against damage risk, since a damage claim can erase the saving.
It also helps to compare modes. Sea freight is usually billed in cubic metres, so a cargo that is costly by air because of volume may suit a slower mode, depending on time and value. For more, see the logistics and transportation guides and the freight density calculator for road shipments.
Where analytics helps
Analytics helps by applying the calculation to your whole shipment history. A table of SKUs, carton sizes and billed weight can show which products are regularly charged on volume, so packaging effort goes where it pays back. Dimensioning scanners also reduce disputes over measurements. The carrier’s rules still determine the final bill.
Common questions
What is the difference between actual weight and volumetric weight?
Actual weight is what the shipment weighs on a scale, including packaging. Volumetric weight is calculated from its dimensions divided by a mode-specific divisor and represents the space it takes. The carrier bills whichever is greater, called the chargeable weight.
What divisor is used for air freight?
Air cargo commonly uses 6,000 cubic centimetres per kilogram, and many express couriers use 5,000. Carriers set their own rules, so use the divisor in your quote or terms. A lower divisor produces a higher volumetric weight and a higher bill for bulky cargo.
Is chargeable weight the same for sea freight?
Not exactly. Sea freight is generally priced by volume in cubic metres, with the usual rule that one cubic metre counts as 1,000 kg when weight and measure are compared. Full container loads are priced per container instead. Confirm the basis with your forwarder.
How can chargeable weight be lowered?
Reduce carton volume with right-sized packaging, remove void space, flat-pack or nest items where possible, and avoid overhang on pallets. Check each change for damage risk. The saving is largest when volumetric weight is well above actual weight.
Sources and further reading
- MIT Center for Transportation and Logistics (MIT CTL)
- Council of Supply Chain Management Professionals (CSCMP)
- Logistics Performance Index (World Bank)