Worked example
One hundred cartons measuring 60 × 40 × 50 centimeters.
- One carton: 0.60 × 0.40 × 0.50 = 0.12 m³.
- One hundred of them: 0.12 × 100 = 12.00 CBM, which is 423.78 cubic feet.
- A 20 ft container holds about 25 CBM in practice, so this load fills roughly 48% of one.
At 12 CBM you are below the point where a full container usually pays off, so this ships LCL. Add another 200 cartons and you are at 36 CBM, past a 20 ft and into 40 ft territory, where booking your own box is normally cheaper per cubic meter as well as faster.
The formula
CBM per carton = L × W × H in meters Total CBM = CBM per carton × number of cartons Cubic feet = CBM × 35.3147 LCL billable = greater of CBM and weight in metric tons
If your dimensions are in centimeters, multiply the three together and divide by 1,000,000. If they are in inches, multiply and divide by 61,024.
Why LCL bills on revenue tons
Ocean LCL is priced per revenue ton, which means whichever is greater of your volume in cubic meters and your weight in metric tons, at a ratio of one CBM to 1,000 kilograms. A pallet of pillows bills on volume; a pallet of tiles bills on weight.
This catches people out on dense cargo. Three CBM of ceramic tile weighing four tonnes bills as four revenue tons, not three, and the quote you were given per CBM suddenly applies to a larger number.
What the forwarder actually quotes
An LCL quote is rarely one number. It is typically an origin charge, an ocean freight rate per revenue ton, a destination charge, and a handful of fixed fees that do not scale with your volume at all.
That last part is what makes small shipments expensive per cubic meter. A documentation fee and a terminal handling charge cost the same whether you ship 2 CBM or 20, so your effective rate per CBM falls sharply as volume rises. When you compare two quotes, compare the landed total for your actual volume, not the headline rate.
It is also why the LCL-to-FCL crossover is not a fixed number. On a lane with high fixed charges, a full container can pay off well below 13 CBM. On a cheap, high-frequency lane it might not pay off until 18. Get both quotes when you are anywhere near the middle.
Common mistakes
- Measuring the product, not the carton. Shipping lines charge for the outside of the packed carton, including any pallet it sits on.
- Using the geometric container volume. A 20 ft container is about 33 CBM of pure geometry but loads 25 to 28 in practice. Plan to the practical figure or you will be repacking on the dock.
- Ignoring weight on dense freight. Always give your forwarder both volume and weight, so the quote reflects the revenue ton you will actually be billed.
- Forgetting pallet height. Cartons on a 15 cm pallet lose that height from every stacking layer inside the container.
- Rounding CBM down. Forwarders round up, usually to the next 0.1 or 1.0 CBM depending on the tariff.
FAQ
What does CBM mean?
Cubic meter, the standard volume unit in ocean and air freight. One CBM is a cube one meter on each side, or about 35.31 cubic feet.
How do I calculate CBM?
Multiply length by width by height in meters, then multiply by the number of cartons. If your dimensions are in centimeters, multiply the three together and divide by 1,000,000.
Why does my quote use weight instead of volume?
Ocean LCL bills on revenue tons, meaning whichever is greater of your CBM and your weight in metric tons, at one CBM to 1,000 kg. Dense freight bills on weight, bulky freight bills on volume.
When should I switch from LCL to a full container?
Around 13 to 15 CBM a full 20 ft container often costs about the same as LCL, and it moves faster because it skips consolidation and deconsolidation. Get both quotes when you are near that line.
Why is the container capacity lower than the internal dimensions suggest?
The geometric cube of a 20 ft container is about 33 CBM, but forwarders quote 25 to 28 because real cartons leave gaps, need bracing, and cannot always be stacked to the ceiling.
Rules last checked: Sep 24, 2026
Estimate only. Confirm with your carrier before booking.