How to Calculate CBM? (Formula)
The standard calculate cbm formula in cm is: L x W x H / 1,000,000. This in cm method converts cubic centimeters into cubic meters and is the baseline for freight quotes across sea and air.
Example: 50 cm x 40 cm x 30 cm = 60,000 cm³. 60,000 / 1,000,000 = 0.06 CBM. Multiply by quantity to get the shipment total.
CBM Calculator in Inches
A cbm calculator in inches should convert inches to cubic feet first, then convert cubic feet to cbm. This inches workflow matches carrier systems and reduces rounding errors.
- Step 1: L x W x H (inches) / 1,728 = CFT
- Step 2: CFT / 35.315 = CBM
| Unit | Equivalent |
|---|---|
| 1 CBM | 35.315 CFT |
| 1 CBM | 61,023 cubic inches |
| 1 CFT | 0.0283 CBM |
Use this cubic feet to cbm conversion whenever your supplier provides inches.
CBM to KG & Volumetric Weight
A cbm to kg estimate compares actual weight with volumetric weight to determine chargeable weight. Air freight commonly uses /6000, so volumetric weight (kg) is L x W x H (cm) / 6,000.
- Sea freight: 1 CBM = 1,000 KG chargeable weight
- Air freight: volumetric weight = L x W x H (cm) / 6,000
If volumetric weight exceeds gross weight, the higher value applies to chargeable weight on the invoice.
Container Capacity: 20ft vs 40ft
For sea shipment planning, container capacity matters. A 20ft container capacity is around 33.2 m³, while a 40ft container is about 67.7 m³ and a 40HQ is 76.3 m³. We recommend a 90% Load Efficiency rule to allow for pallets, gaps, and carton deformation.
| Container | Theoretical CBM | Recommended (90%) |
|---|---|---|
| 20GP | 33.2 m³ | 28 m³ |
| 40GP | 67.7 m³ | 58 m³ |
| 40HQ | 76.3 m³ | 68 m³ |
Shipping to Amazon FBA
Shipping from china to usa for Amazon FBA requires accurate carton labels, palletization, and appointment scheduling. Align the declared CBM and weights with your booking to avoid rework at the receiving dock.
Freight class is used for LTL shipments in the USA. Lower density means higher freight class and higher cost, so accurate measurements help avoid reclassification fees and delays.