CBM (cubic metres) is the standard unit for measuring cargo volume in international shipping. Understanding CBM helps you choose the right container size, estimate freight costs, and maximise space utilisation.
CBM is calculated by multiplying the three dimensions of a carton and then multiplying by quantity:
If your dimensions are in centimetres, divide by 1,000,000:
| Carton Size (cm) | Qty | Calculation | Total CBM |
|---|---|---|---|
| 40 × 30 × 25 | 100 | 40×30×25×100÷1,000,000 | 3.0 CBM |
| 60 × 40 × 40 | 50 | 60×40×40×50÷1,000,000 | 4.8 CBM |
| 30 × 24 × 13 | 1000 | 30×24×13×1000÷1,000,000 | 9.36 CBM |
| 50 × 50 × 50 | 200 | 50×50×50×200÷1,000,000 | 25.0 CBM |
| Container Type | Internal Volume (CBM) | Practical Load | Utilisation |
|---|---|---|---|
| 20ft Standard | 33.2 m³ | 25–28 m³ | 75–85% |
| 40ft Standard | 67.3 m³ | 55–62 m³ | 80–92% |
| 40ft High Cube | 76.3 m³ | 65–72 m³ | 85–94% |
| 40ft Reefer HC | 66.7 m³ | 54–62 m³ | 80–93% |
Why not 100% utilisation? Practical loading rarely achieves 100% because of irregular carton stacking, weight limits reached before volume is full, or loading gaps near doors. A well-planned load achieves 80–90%.
For LCL (Less than Container Load) shipments, you are charged by CBM or weight — whichever gives the higher freight value (called chargeable weight):
For FCL (Full Container Load), you pay for the whole container regardless of how full it is — so maximising CBM utilisation directly reduces your cost per carton.
When using pallet loading, your effective CBM is lower than floor loading because:
ContainerLoad calculates both the CBM and the actual carton count accounting for all these factors.
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