CBM Calculator — Cubic Meters for Shipping and Container Loading
Calculate the CBM (cubic meters) of a shipment from carton size and quantity, plus cubic feet, sea-freight W/M revenue tons, air chargeable weight and how full a 20 ft, 40 ft or 40 ft HC container is.
How it works
CBM per carton = length × width × height (in metres) · Total CBM = CBM per carton × cartons · ft³ = m³ × 35.315 · Sea LCL billable (W/M) = greater of CBM or gross weight in tonnes · Air volumetric weight (kg) = CBM × 1,000,000 ÷ 6,000 · Air chargeable weight = greater of volumetric and actual weight · Cartons that fit ≈ container volume × 85% ÷ carton CBM
CBM (cubic metre, m³) is the unit freight forwarders use to quote and plan international shipments. Sea consolidators (LCL) bill on "weight or measure" (W/M): one revenue ton is 1 m³ or 1,000 kg, whichever is greater. Airlines bill the greater of actual and volumetric weight using the IATA factor of 6,000 cm³ per kg. Full containers are planned by volume: a 20 ft box has about 33 m³ inside, a 40 ft about 67–68 m³ and a 40 ft high cube about 76 m³, but real loads rarely use more than 80–90% because of carton shapes and gaps, so the carton count assumes 85% stowage.
Worked example
100 cartons of 60 × 40 × 50 cm weighing 12 kg each: each carton is 0.6 × 0.4 × 0.5 = 0.1200 m³, so the shipment is 12.000 m³ (423.78 ft³) and 1,200.00 kg. By sea LCL it bills as 12.000 revenue tons (volume beats 1.2 t); by air the volumetric weight is 12 × 1,000,000 ÷ 6,000 = 2,000.00 kg, which is the chargeable weight. It fills 36.14% of a 20 ft container, where about 235 such cartons fit.
Sources: IATA — Dimensional weight (volumetric) rule · Wikipedia — Intermodal container dimensions
Frequently asked questions
How do I calculate CBM?
Multiply length × width × height of one carton in metres, then multiply by the number of cartons. A 60 × 40 × 50 cm carton is 0.6 × 0.4 × 0.5 = 0.12 m³; 100 of them are 12 m³. If you measure in inches, multiply the three inches together and divide by 61,024.
How many CBM fit in a 20 ft or 40 ft container?
The internal volume is about 33.2 m³ (20 ft), 67.7 m³ (40 ft) and 76.3 m³ (40 ft high cube). Realistic loadable volume is lower — roughly 25–28, 55–58 and 65–68 m³ — because cartons never fill every gap.
What is W/M in sea freight?
Weight or measure: LCL freight is charged per revenue ton, which is 1 m³ or 1,000 kg, whichever gives the larger number. Light, bulky cargo pays by volume; dense cargo pays by weight.
How is air chargeable weight calculated from CBM?
Air freight uses a volumetric factor of 6,000 cm³ per kg (1 m³ = 166.67 kg). The airline charges the greater of that volumetric weight and the actual gross weight. Express couriers often use 5,000 cm³/kg instead, which gives a higher volumetric weight.
How do I convert CBM to cubic feet?
Multiply by 35.315. 1 m³ = 35.315 ft³, so 12 m³ = 423.78 ft³. To go from cubic feet to CBM divide by 35.315.
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