🚢 CBM Calculator
Carton volume in cubic meters, and how many fit in a 20ft or 40ft container.
Carton size (cm)
Sea freight is priced by space, not weight — forwarders quote a rate per CBM (one cubic meter). Enter your cartons (or tap an example) to get the number that drives your quote.
What is CBM?
CBM (cubic meter) is the standard unit of cargo volume in sea freight: length × width × height in meters, times the number of cartons. Freight forwarders quote LCL (less than container load) rates per CBM, so this number is effectively the price driver of ocean shipping.
Container capacities
The nominal volumes are 33.2 m³ for a 20ft container, 67.7 m³ for a 40ft, and 76.4 m³ for a 40ft high cube. The counts above divide the container volume by your carton volume — real-world loading loses 5–15% to stacking geometry and pallets, so treat the figure as an upper bound and plan for a margin.
When does sea freight beat air?
A common rule of thumb: above roughly 2 CBM or 500 kg, sea (LCL) usually wins on cost despite the longer transit; below that, courier or air freight is often cheaper once handling fees are counted. Rates move, so quote both when near the boundary.