Three different numbers
| Measure | What it is | Unit |
|---|---|---|
| CBM | The space the cargo takes | m³ |
| Volumetric weight | That space expressed as a weight, using the carrier's factor | kg or lb |
| Chargeable weight | The greater of the actual weight and the volumetric weight | kg or lb |
CBM is a measurement. Volumetric weight is a pricing convention built on top of it. Chargeable weight is the result of comparing that convention with the scale.
From CBM to volumetric weight
Carriers state a divisor (cubic centimetres per kilogram) or the equivalent factor (kilograms per cubic metre). They are two ways of writing the same rule:
kg per CBM = 1,000,000 ÷ divisor Divisor 6000 → 166.67 kg per CBM (common air freight planning value) Divisor 5000 → 200 kg per CBM (common courier value)
So with a 6000 divisor, 2.5 CBM of cargo has a volumetric weight of 2.5 × 166.67 = 416.67 kg.
From volumetric weight to chargeable weight
The carrier then compares the volumetric weight with the actual gross weight and charges on the greater:
Actual weight = 300 kg Volumetric weight = 416.67 kg Chargeable weight = 416.67 kg (volumetric is greater)
If the same 2.5 CBM weighed 600 kg, the chargeable weight would be 600 kg, because the cargo is dense enough that weight decides the price.
What about sea freight?
LCL sea freight uses a similar comparison called weight or measure (W/M): one CBM is set against one tonne, and the greater number of "revenue tons" is charged. The LCL Freight Calculator applies it with your rate.
Which tool to use
- Need the volume only: CBM Calculator.
- Parcels with a courier divisor: Dimensional Weight Calculator.
- Air cargo: Air Freight Chargeable Weight Calculator.
For more on the comparison itself, see Actual Weight vs Volumetric Weight and What Is Chargeable Weight?