CBM · Cubic feet · Container fill

CBM calculator

Know whether the cartons fit the box before you book it.

Enter carton size, weight and count to get CBM, cubic feet, total weight, and how full a 20 ft, 40 ft or 40 ft high cube container gets.

Last updated 2026-09-27. Math runs in your browser, no data leaves your computer.

Measure one carton at its outside edges, bulge included, because the loader stacks and the forwarder bills on the outside size. Pick the units you measured in and every result converts for you.

Units

Take each side from a tape on a packed carton rather than the carton maker's drawing, since a small error on every carton adds up across a full container load.

Use the total from the packing list, because the booking asks for the shipment total, not one carton.

Enter the gross weight with packaging so the tool can check the load against each container's payload.

Tick this when the cartons carry an orientation arrow, because the carton count then only turns them on the floor and never onto a side.

Before the booking, screen the name on the invoice. Shipment pre-check is on the paid plans, from USD 59 a month.

General guidance only. Verify against the cited primary sources before you commit to a shipment, declaration, or contract.

How the CBM and container fill numbers work

CBM is length times width times height in meters, multiplied by the carton count. Centimeter sizes divide by 1,000,000 to give cubic meters, while inch sizes go to cubic feet by dividing cubic inches by 1,728, then to cubic meters at 0.02831685 m³ per cubic foot, the factor in NIST SP 811 Appendix B.8, and pounds convert at 0.45359237 kg.

The container figures come from Ocean Network Express. Its 20 ft dry box measures 5,898 by 2,350 by 2,390 mm inside with a 33.1 m³ load capacity, the 40 ft measures 12,032 by 2,350 by 2,390 mm with 67.6 m³, and the 40 ft high cube measures 12,032 by 2,350 by 2,695 mm with 76.2 m³. Payloads are 28,330 kg, 26,840 kg and 28,800 kg in the same order.

The volume column divides your total CBM by that load capacity. The carton column is stricter, because it tries each side of the carton as the height, fills the floor with whole cartons in straight rows or in two blocks turned against each other, and stacks as many full layers as the inside height allows. The gap between the two numbers is space lost to carton size, and no loader recovers all of it.

A loaded container is also limited by the truck leg at each end. Road weight limits differ by state and country and often sit below the box payload, so ask the trucker for the legal load before you plan a heavy container to the ONE figure.

Worked example. 1,000 cartons marked this side up

The booking. A buyer orders 1,000 cartons at 50 by 40 by 35 cm and 12 kg each. Each carton is 0.07 m³, so the shipment is 70.0 m³ and 12,000 kg. Against the 76.2 m³ of a 40 ft high cube that is 91.9% of the volume and well inside the payload, which looks fine on paper, so the buyer books one 40 ft high cube.

The failure. The cartons are marked this side up, so the 35 cm side has to stay vertical. That fits seven layers into the 2,695 mm inside height, and the best floor pattern takes 138 cartons a layer, so the box holds 966 and 34 cartons stay on the dock at the factory. The choice in front of the buyer is the usual one: change the cargo, or change the equipment.

The fix. With the upright box ticked, the tool shows 966 cartons for the 40 ft high cube before anything is booked. The buyer loads 966 cartons, 67.62 m³ and 11,592 kg, into the high cube and sends the other 34 cartons, 2.38 m³, as LCL on the same sailing. The load ships and nothing waits at the factory.

Planning drums, IBCs or pallets instead of cartons? The pallet calculator works out boxes per pallet and pallets per 20 ft, 40 ft and 53 ft trailer, with the door height checked.

Frequently asked

How do I work out CBM for a carton?

Multiply length, width and height in meters, then multiply by the number of cartons. A carton of 50 by 40 by 35 cm is 0.5 × 0.4 × 0.35 = 0.07 m³, so 1,000 of them are 70 m³. From inches, divide the cubic inches by 1,728 to get cubic feet and multiply by 0.02831685, the NIST SP 811 factor, to get cubic meters.

How many CBM fit in a 20 ft, 40 ft and 40 ft high cube container?

Ocean Network Express lists a load capacity of 33.1 m³ for its 20 ft dry box, 67.6 m³ for the 40 ft and 76.2 m³ for the 40 ft high cube. Those are the empty inside volumes. Cartons never fill every corner, so plan below the full figure and check the carton count this tool prints for your carton size.

Why does the carton count that fits come out lower than the volume suggests?

A container only takes whole cartons, so a 50 cm carton along the 2,350 mm inside width of a ONE container fits four times with 350 mm left over, and that strip is lost on every layer. The carton count tries each side of the carton as its height, fills the floor with whole cartons, and reports the best whole number, which is the number the loader actually works with.

Does the tool check container weight too?

It does, by comparing your total gross weight with the payload ONE lists for each box: 28,330 kg for the 20 ft, 26,840 kg for the 40 ft and 28,800 kg for the 40 ft high cube rated at 32,500 kg gross. Road limits for the truck leg are often lower than the box payload, so confirm them with the trucker before you load to the full figure.

Is CBM the same as the chargeable volume on an LCL quote?

LCL is billed per W/M, the larger of cubic meters and metric tonnes, so the CBM from this tool is one half of that comparison. Dense cargo bills on weight instead. Run the chargeable weight calculator when you need the billed figure for sea, air and courier side by side.

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Sourzi shows what official files say. It is not customs or legal advice. For a binding answer, ask a licensed customs broker, a CBP ruling or an Australian Border Force Tariff Advice.

File dates and links are on Data sources.