How this calculator works
CBM is length × width × height in metres. A 60 × 40 × 40 cm carton is 0.6 × 0.4 × 0.4 = 0.096 m³. Multiply by the number of cartons for the shipment. One cubic metre is about 35.3 cubic feet.
Air freight bills the higher of actual weight and volumetric weight. The standard air factor is 6,000 cm³ per kilogram, so each cubic metre counts as 166.67 kg.
Sea freight for less-than-container loads (LCL) bills by “weight or measure”: each cubic metre or each 1,000 kg is one unit, whichever is higher. Most goods are billed on volume.
Container capacity uses typical internal volumes: about 33 m³ for a 20 ft, 68 m³ for a 40 ft and 76 m³ for a 40 ft high cube. Cartons never fill a container perfectly, so the usable-space setting (85% by default) gives a realistic count.
Heavy goods such as tiles or machinery can reach a container’s maximum payload before it is full by volume. Check the weight limit with your forwarder.
Worked example
120 cartons of 60 × 40 × 40 cm, 12 kg each
- Per carton: 0.6 × 0.4 × 0.4 = 0.096 m³. Total: 0.096 × 120 = 11.52 m³ (about 407 cubic feet).
- Gross weight: 120 × 12 = 1,440 kg.
- Air freight: 11.52 m³ × 166.67 = 1,920 kg volumetric, which is more than 1,440 kg, so you pay for 1,920 kg.
- Sea LCL: 11.52 W/M (volume beats 1.44 tonnes). At 85% usable space a 20 ft container holds about 293 of these cartons, so this shipment fits in one.
Questions people ask
When is a full container cheaper than LCL?
It depends on the route and rates, but many importers find a 20 ft container becomes worth pricing from roughly 13 to 15 m³, since LCL is charged per cubic metre plus handling fees. Ask your forwarder for both quotes.
How many CBM fit in a 20 ft container?
Its internal volume is about 33 m³, but in practice 25 to 28 m³ of cartons is common, depending on carton sizes and how they stack.
How do I convert cubic feet to CBM?
Divide cubic feet by 35.315. For example, 400 cubic feet is about 11.3 m³.
Why is my air freight quote based on more weight than my goods?
Light, bulky goods are billed on volumetric weight. If 1 m³ of cartons weighs less than 166.67 kg, you pay for 166.67 kg per cubic metre.
Last reviewed October 2, 2026