Shipping & logistics
Calculate cubic volume for boxes, cartons, or shipments.
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CBM calculator guide
CBM is the cubic metre volume of a shipment, and it is the number a freight forwarder asks for before quoting sea LCL or comparing it with air. This calculator takes the outer length, width, and height of one carton in centimetres, converts the product to cubic metres, and multiplies by the carton count. Small ecommerce sellers use it to turn a supplier’s packing list into a bookable volume, to check whether an order will fit a pallet or a share of a 20ft container, and to see how far a shipment is from the point where sea freight starts charging by weight instead of space. Measure the packed carton, not the product: freight is billed on the box that actually travels. The result is total volume only; it does not apply a minimum charge, a utilisation factor, or the weight-or-measure comparison your forwarder will make on the final invoice.
CBM (m³) = length (cm) × width (cm) × height (cm) ÷ 1,000,000 × quantity. Per-carton volume (m³) = CBM ÷ quantity. Litres = CBM × 1,000.
Worked example: one carton measuring 40 cm × 30 cm × 25 cm holds 40 × 30 × 25 = 30,000 cm³, which is 30,000 ÷ 1,000,000 = 0.03 m³. Ten identical cartons give 0.03 × 10 = 0.3 m³, or 300 litres. Under the sea LCL weight-or-measure rule, 0.3 m³ is billed as 0.3 revenue tonnes unless the ten cartons weigh more than 300 kg. The calculator shows 0.03 m³ per carton and a shipment total of 0.3 m³.
All three dimensions are entered in centimetres and quantity is a plain count. Supplier sheets often list millimetres: divide by 10 before entering. For inches, multiply by 2.54. For metres, multiply by 100. The per-carton row is shown to four decimals because small cartons round to zero at two. One cubic metre equals 35.315 cubic feet if a US quote uses ft³.
Carriers bill on whichever is greater, actual weight or volumetric weight, so treat this result as the number to compare against your carrier's own quote. Divisors, rounding rules, and surcharges differ between carriers and between domestic and international services, and they change with contract terms. Confirm the current rules for your account before you price a shipment. On this page the figure rests entirely on length, width, height, quantity, market / jurisdiction, effective date, data source, update owner and review date, so start there if the cbm calculator returns something you did not expect.
Good to know: the most common error is entering product dimensions from a listing instead of the outer master-carton size, which understates volume by the packaging and any inner cartons. Keep every dimension in centimetres; mixing a millimetre height with centimetre length inflates the result tenfold. Cartons stacked on a pallet are measured as one pallet, including overhang and the pallet deck, so a palletised LCL booking is usually more than the sum of the cartons.
Shipping results depend on carrier, service, route, divisor, rounding, surcharges, and contract terms. Confirm the current carrier rule before buying a label or quoting a customer.
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How it works
Calculate cubic volume for boxes, cartons, or shipments. This tool explains the calculation so you can adjust the assumptions to match your situation.
Worked example
With Length = 40 cm · Width = 30 cm · Height = 25 cm · Quantity = 10 → 0.3 m³ (total shipment volume). Change an input above and this example updates with your numbers.
Common questions
Multiply the carton length, width, and height in centimetres, divide by 1,000,000 to get cubic metres, then multiply by the number of cartons. A 40 × 30 × 25 cm carton is 0.03 m³, so 10 cartons are 0.3 m³.
A standard 20ft dry container has about 33 m³ of internal space (roughly 5.9 × 2.35 × 2.39 m). Realistic loose-carton loading uses 80–85% of that, so plan on about 26–28 m³ of cartons.
Sea LCL is charged per revenue tonne, where 1 m³ counts as 1,000 kg. The forwarder bills the greater of actual weight in tonnes and volume in cubic metres, so a 0.3 m³ shipment weighing 120 kg pays for 0.3 revenue tonnes.
Air cargo uses a different rule: volume in cm³ divided by 6,000 gives volumetric kg. 0.3 m³ is 300,000 cm³, which is 300,000 ÷ 6,000 = 50 kg of volumetric weight. If the actual weight is higher, the actual weight is charged.
Use the outer dimensions of the master carton as it will be handed to the carrier, including any strapping or corner boards. Inner cartons and product dimensions are for packing, not for freight quotes.