Every furniture import quote, freight invoice and container plan rests on one number: CBM, the cubic metre. Getting CBM wrong at the quote stage produces freight bills that arrive higher than the plan, containers that load short, and profit that leaks out carton by carton. The calculation itself is simple arithmetic; the skill is applying it to real furniture cartons, which are rarely perfect cubes.

The Basic CBM Formula

CBM measures the space a carton occupies. The formula is length times width times height, with all dimensions in metres. A carton measuring 200 cm by 100 cm by 80 cm converts to 2.0 m by 1.0 m by 0.8 m, which multiplies to 1.6 CBM. In centimetres, divide the product by one million: 200 times 100 times 80 equals 1,600,000, divided by one million equals 1.6 CBM.

For a shipment of mixed cartons, calculate each carton’s CBM and sum the list. The total CBM is the number that goes on the booking, and the customs declaration of goods measurement follows the harmonized conventions that the WCO maintains for international trade documentation. A 5 percent error on a 40HQ booking is roughly 3 CBM, which is the difference between a container that closes and one that leaves cartons behind.

Worked Examples for Furniture

A three-seat sofa in a corrugated carton of 215 by 95 by 85 cm occupies 1.74 CBM. A dining table flat-packed at 165 by 95 by 25 cm occupies 0.39 CBM, and four dining chairs packed two per carton at 95 by 60 by 60 cm occupy 0.34 CBM per carton. A bedroom set of bed, two nightstands and dresser typically lands between 3.5 and 4.5 CBM depending on whether the bed ships knock-down or assembled.

The packing method decides the CBM. The same sofa assembled occupies its full carton; shipped with legs removed and backrest unbolted, the carton shrinks 20 to 30 percent and the per-unit freight drops by the same ratio. Factories know this, which is why the FOB quote must always state the packing way: a low price with assembled packing can carry higher freight than a higher price with knock-down packing.

Container Capacities and Usable Space

The standard container figures every importer should memorise: a 20GP holds 33 CBM of volume with 28 CBM realistically usable for furniture; a 40GP holds 67 CBM with 58 CBM usable; a 40HQ holds 76 CBM with 68 CBM usable. Furniture loses the gap because cartons are rectangular and container walls curve, because palletised cargo wastes the headroom, and because mixed carton sizes never tessellate perfectly.

Loading plans work carton by carton. A 40HQ at 68 usable CBM fits roughly 38 sofas at 1.74 CBM each with the balance taken by flat-pack cartons of chairs and tables. The experienced forwarder builds the plan from the actual carton list rather than the total, because 68 CBM of big cartons loads differently from 68 CBM of small ones. US importers should also keep the entry paperwork aligned with the loaded quantity, following the process guidance CBP publishes, since overage and shortage both trigger examination risk.

Volumetric Weight for Air Freight

Air freight charges the larger of actual weight and volumetric weight, because aircraft sell space, not mass. The industry factor is 1 CBM equals 167 kg chargeable weight under the rules that IATA standardises: volumetric weight in kg equals CBM multiplied by 167.

A flat-pack chair carton of 0.34 CBM and 24 kg actual weight carries 57 kg volumetric weight, so the airline bills 57 kg. Upholstered furniture is the extreme case: a sofa at 1.74 CBM bills 291 kg volumetric against 75 kg actual, which is why air freight for sofas costs more than the sofa itself. Importers use air freight for samples, showroom pieces and emergency replacements, and they calculate the chargeable weight before quoting the customer, because the number always surprises people who think in kilos.

Sea vs Air: Where Each Wins

Sea freight bills by CBM and wins for any full-carton volume: a 1.74 CBM sofa moves for USD 90 to USD 140 in a 40HQ slot at current rates. Air freight bills by chargeable weight and wins for urgent, small or high-value pieces where the inventory cost of waiting exceeds the freight premium. The crossover point varies by product value, but the arithmetic is the same on both sides: measure the carton, calculate the CBM, and let the chargeable metric decide.

For freight planning support and sourcing help, visit our sourcing services or the contact page.

For the full 40-point sofa inspection protocol, see our sofa inspection checklist.

Paper errors stop containers faster than production delays; our furniture import documents checklist lists every document and its cut-off date.

Frequently Asked Questions

• How do I calculate CBM for a furniture carton?
  Multiply length, width and height in metres. In centimetres, multiply the three dimensions and divide by one million. A 200 x 100 x 80 cm carton equals 1.6 CBM.
• How many CBM does a sofa carton take?
  A three-seat sofa in a 215 x 95 x 85 cm carton occupies 1.74 CBM. Knock-down packing with legs removed and backrest unbolted shrinks the carton 20 to 30 percent.
• How much furniture fits in a 40HQ container?
  A 40HQ holds 76 CBM of volume with about 68 CBM usable for furniture. At 1.74 CBM per sofa, that is roughly 38 sofas with the balance taken by flat-pack cartons.
• How is volumetric weight calculated for air freight?
  Volumetric weight in kg equals CBM multiplied by 167. A 0.34 CBM chair carton bills 57 kg volumetric weight against 24 kg actual, and the airline charges the higher figure.