CBM — cubic meters — is the unit sea freight thinks in. LCL shipments are priced per CBM, container choice depends on total CBM, and the difference between an accurate and a guessed CBM figure is the difference between a quote that holds and a surprise invoice.
The formula
For each carton: length × width × height in centimetres, divided by 1,000,000. Multiply by the number of cartons and sum across carton types.
- Carton 50 × 40 × 30 cm = 60,000 cm³ = 0.06 CBM
- 40 cartons × 0.06 = 2.4 CBM
- Mixed shipment? Calculate each size separately and add them up
Why LCL cares so much
In LCL (Less than Container Load) your cargo shares a container with other shippers, and you pay for the slice of space you occupy — so the CBM figure is the price basis. Very dense cargo is sometimes charged on weight instead (commonly where one ton exceeds one cubic metre), but for typical consumer goods, volume rules. Origin and destination handling charges also scale with CBM, which is why quotes should show the whole picture, not just the ocean leg.
Real dimensions beat catalog dimensions
The classic error is calculating from the supplier's quoted carton size while the factory actually ships a slightly larger box, adds double-walled cartons, or palletizes. A few centimetres per side across dozens of cartons quietly adds real CBM. This is why we measure cargo at pickup — the verified figure protects your quote in both directions.
When to stop counting CBM and book a container
As volume grows, FCL (your own container) overtakes LCL: from roughly the mid-teens of CBM, a 20ft container (about 26–28 usable CBM) often costs little more than the equivalent LCL charges while loading once, sailing sealed, and avoiding shared-container handling. A 40ft or 40HQ continues the logic for bigger loads. If your calculation lands near the crossover, ask us to quote both — the comparison is free and occasionally very pleasant.
