How to calculate CBM (cubic meters)
CBM = length × width × height (in meters) × quantity. For a carton 50 × 40 × 30 cm (10 of them):
- Per carton: 0.5 m × 0.4 m × 0.3 m = 0.06 m³
- Total: 0.06 m³ × 10 = 0.6 m³ (21.19 ft³)
Volumetric weight: air, courier and sea freight
Carriers bill whichever is greater: your shipment's actual weight, or its volumetric (dimensional) weight -- a stand-in for how much space it takes up.
- Air freight: volume (cm³) ÷ 6,000 = kg. This shipment: 100 kg.
- Courier/express: volume (cm³) ÷ 5,000 = kg (a smaller divisor, so a higher volumetric weight). This shipment: 120 kg.
- Sea freight (LCL): 1 CBM = 1,000 kg under the common "weight or measurement" rule. This shipment: 600 kg.
Enter your shipment's actual weight above to see the chargeable weight (the greater of actual vs. volumetric) for air and courier freight.
Container fill estimate
| Container | Nominal capacity | % full | Containers needed |
|---|---|---|---|
| 20' standard container | 33 m³ | 1.8% | 1 |
| 40' standard container | 67 m³ | 0.9% | 1 |
| 40' high-cube container | 76 m³ | 0.8% | 1 |
Nominal (rounded, commonly-cited) internal capacity -- usable capacity is always lower once pallets and loading pattern are accounted for.
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Frequently asked questions
How is CBM calculated?
CBM (cubic meters) = length × width × height, in meters, then multiplied by quantity. For a carton 50 × 40 × 30 cm (convert to meters: 0.5 × 0.4 × 0.3), that's 0.06 m³ per carton; 10 cartons = 0.6 m³.
How do I convert CBM to cubic feet?
Multiply cubic meters by 35.3147 (1 m³ = 35.3147 ft³). 1 m³ equals 35.31 ft³.
What is volumetric (dimensional) weight?
A billable weight based on the SPACE a shipment takes up, not just its actual weight -- because a large, light box still takes up room a carrier could have used for something heavier. Carriers charge whichever is greater: the actual weight or the volumetric weight. Air freight commonly divides total volume (in cm³) by 6,000; many couriers/express services divide by 5,000 instead, giving a higher (more expensive) volumetric weight for the same box.
How do I calculate volumetric weight for air freight?
Volume in cm³ ÷ 6,000 = kg. For 10 cartons at 50×40×30 cm: total volume is 600,000 cm³, so 600,000 ÷ 6,000 = 100 kg volumetric weight.
What is the difference between volumetric weight and chargeable weight?
Volumetric weight is just the space-based calculation above. Chargeable weight is whichever is GREATER of the actual weight and the volumetric weight -- that's the number you're actually billed on. A shipment that's 100 kg by volume but only 50 kg by scale is still charged at 100 kg (the volumetric figure, since it's bigger) for air freight.
How do I convert CBM to kg for sea freight?
Sea freight (LCL, less-than-container-load) commonly uses a "weight or measurement" (W/M) rule: 1 CBM is treated as 1,000 kg for rate purposes, and you're charged on whichever is greater. 0.6 m³ converts to 600 kg under this rule.
How many CBM fit in a shipping container?
Commonly-cited NOMINAL internal capacities are around 33 m³ for a 20ft standard container, and larger for 40ft and 40ft high-cube containers. A shipment of 0.6 m³ would fill about 1.8% of a 20ft container by that nominal figure -- but usable capacity is always somewhat lower once pallets, dunnage and how boxes actually stack are accounted for, so treat the container-fill table above as a rough planning estimate, not a load plan.
Should I measure in centimeters or inches?
Either works -- switch the unit toggle above and the calculator converts inches to centimeters automatically (1 inch = 2.54 cm) before computing volume. Most international freight quotes are in CBM (cubic meters), so cm is the more common convention, but US domestic box dimensions are often labeled in inches.
Does this include packaging or pallet dimensions?
Only what you enter. If you're calculating shipment volume for a freight quote, measure the OUTER dimensions of the actual cartons or pallets that will ship -- not the product inside them -- since that's what determines the space a carrier needs to allocate.
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