Foreign-trade Glossary + Calculators
Measurement
Density Ratio (Weight-to-Volume)
A shipment's weight per cubic meter (kg/CBM), used to decide weight- vs volume-based charging and whether cargo is bubble cargo.
Density ratio (also cargo density) = total gross weight (kg) ÷ total volume (CBM), in kg/CBM, measuring how heavy a cubic meter of the cargo is. It decides whether freight is charged by weight or by volume and is the key test for bubble vs dense cargo.
Key points:
- The air/courier threshold is the inverse of the volumetric divisor: ÷6000 corresponds to ~167 kg/CBM, ÷5000 to ~200 kg/CBM. Below the threshold, freight follows volumetric weight (bubble cargo); above it, actual weight (dense cargo).
- The sea-LCL threshold is 1000 kg/CBM (the revenue-ton rule): below bills on volume tons, above on weight tons.
- The same cargo has different thresholds per channel — sea 1000, air 167, courier 200 — so assess each separately when comparing.
Common pitfall: applying one threshold to every channel misclassifies cargo. Compute density first, then compare against the target channel's threshold to choose whether to cut volume or weight.
FAQ
- How do I calculate the density ratio?
- Divide total gross weight (kg) by total volume (CBM). E.g. 480 kg over 2.4 CBM gives 200 kg/CBM.
- What density counts as dense vs bubble cargo?
- Use the channel threshold: ~167 kg/CBM for air, ~200 for courier, 1000 for sea LCL. Below is bubble cargo billed by volume; above is dense cargo billed by weight.
Related terms
Sources: https://www.iata.org/en/programs/cargo/ · https://www.maersk.com/logistics-explained