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CBM Calculator for Shipping: Cartons, Weight and Containers

Work out the cubic meters of a shipment from carton sizes and counts, its volumetric weight, and how many cartons fit a 20 ft or 40 ft container. Enter each carton size with its count and weight, pick a 20 ft, 40 ft or 40 ft high cube container, and get the CBM, the air and courier chargeable weight and the LCL weight or measure.

Your numbers

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Share of the container a real load uses. 85% is a typical figure; pallets, gaps and how high cartons stack decide. Edit it.

Carton size 1
cm
cm
cm
kg

Up to 6 sizes. Measure the outside of the carton, and use the gross weight of one packed carton.

Total CBM

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Cartons
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In cubic feet
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Gross weight
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Air volumetric weight (÷ 6,000)
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Air chargeable weight
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Courier volumetric weight (÷ 5,000)
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Courier chargeable weight
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LCL weight or measure
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Fill of a 20 ft container
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Containers needed at 85%
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Share of max payload
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The divisors and the 1 CBM = 1,000 kg ratio are common rules; your carrier's or forwarder's terms decide.

The calculation runs in your browser and ParrotNotes does not store your numbers. They sit in the page address so you can bookmark or share the result.

How to calculate CBM

CBM is a cubic meter, the unit ocean freight, forwarders and most suppliers outside the US quote in. For one carton, multiply length × width × height in centimeters and divide by 1,000,000; then multiply by the number of cartons. Measure the outside of the packed carton, bulges included.

Worked example: a carton of 60 × 40 × 50 cm is 120,000 cm³, or 0.12 CBM. Fifty of them are 6 CBM, about 211.9 cubic feet. In inches, multiply each side by 2.54 first: 100 cartons of 24 × 18 × 12 in are 8.5 CBM, exactly 300 cubic feet. With several carton sizes, add a row per size; the table under the result shows each one.

Volumetric weight: air and courier

Planes and vans fill up by space before weight, so carriers charge light, bulky cargo by its volume turned into a weight. For air freight, Maersk gives the formula length × width × height in cm ÷ 6,000, the divisor set by IATA, and you pay on the higher of that and the gross weight. Express couriers use a smaller divisor: DHL Express uses ÷ 5,000, which is 200 kg per cubic meter.

The 50 cartons above weigh 900 kg, but their 6 CBM are 1,000 kg by air and 1,200 kg by courier, so the bill is on 1,000 kg or 1,200 kg. Heavy, dense goods work the other way: ten 150 kg cartons of 0.06 CBM are charged on their 1,500 kg. Some airlines use 5,000 too; check the carrier's divisor before you quote.

LCL: weight or measure

Less-than-container-load ocean freight is usually priced per W/M, weight or measure: the shipment's cubic meters against its weight in metric tons, whichever is higher. Maersk's LCL terms count 1 CBM as equal to 1,000 kg. So 6 CBM weighing 900 kg is 6 W/M, charged by volume, and 0.6 CBM weighing 1,500 kg is 1.5 W/M, charged by weight.

Not every forwarder uses the same ratio, and most add a minimum charge per shipment; the calculator shows the common rule, and your forwarder's quote decides.

Container sizes and how full yours gets

Pick the container with the buttons above the calculator. The figures are Hapag-Lloyd's published inside sizes, capacity and maximum payload; containers vary a little by maker. The loading allowance (85% to start, edit it) stands in for gaps, pallets and cartons that cannot stack to the roof, so the containers-needed figure is closer to a real load than the raw fill.

Inside dimensions, capacity and maximum payload of standard shipping containers (Hapag-Lloyd)
ContainerInside L × W × H (mm)CapacityMax payload
20 ft standard5,900 × 2,352 × 2,39533.2 m³28,130 kg
40 ft standard12,032 × 2,352 × 2,39567.7 m³28,750 kg
40 ft high cube12,032 × 2,350 × 2,70076.3 m³28,600 kg

Cartons per container: what the volume number leaves out

With one carton size, the calculator divides the usable volume by one carton: 235 cartons of 0.12 CBM in a 20 ft at 85%. That is a volume figure. It does not turn cartons to fit the width, check how many layers the bottom carton can carry, or allow for pallets and the door opening. Use it to size the order; a load plan from the forwarder or the warehouse gives the count that ships.

Weight can run out before space. Dense goods such as tiles, drinks or chemicals reach the container's maximum payload, and often the road weight limit where it is trucked, long before the box is full; the payload share in the result shows how close you are.

CBM and freight class are different numbers

US LTL trucking does not price by CBM: it uses the NMFC freight class, worked out from the shipment's density in pounds per cubic foot. Same cartons, different question. For a US LTL quote, run the dimensions and weight through the Freight Class Calculator, which shows the density scale and its source.

For reps who quote freight

Distributor, packaging, wholesale and food-broker reps get the question on the call: how many cases fit a container, and what will freight add per unit. The CBM answers the first; the quote from the forwarder answers the second.

The numbers come from the conversation: which pack size, how many per carton, the ship date, the port, whether the buyer will take a full container. Those details move as the deal moves, and they are what the freight quote has to match.

Sources, checked October 2026. All results are estimates; the carrier's terms decide:

More for distributor, packaging and wholesale reps: Distributor sales, Packaging sales, Wholesale sales rep, What is a food broker.

The cube is the easy part of the quote

The buyer's call is where the order takes shape: carton counts, pack sizes, the ship date and the port. Record the call in ParrotNotes and get a summary with the numbers and next steps, so the freight quote matches what was agreed.

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