What the freight company actually charges for
You are shipping ten boxes overseas and the quote says $120 per CBM. The boxes are light but bulky, so the price depends on volume, not weight. CBM stands for cubic meters, the standard unit of freight volume, and one wrong measurement can swing the bill by hundreds of dollars. Getting the CBM right is the difference between a fair quote and an expensive surprise.
The CBM formula
Formula: CBM = length x width x height, with all three dimensions in meters. For multiple identical packages, multiply by the number of packages: total CBM = (length x width x height) x quantity.
Length, width, and height are the outer dimensions of the packed box, not the product inside, because the ship charges for the space your cargo occupies. If you measure in centimeters, divide each by 100 first to get meters.
How to use this calculator
- Measure the outside of one packed box: length, width, height.
- Convert every dimension to meters (centimeters divided by 100).
- Enter the quantity of identical boxes.
- Read the total CBM and multiply by your rate to estimate the cost.
Worked example
Each box measures 250 cm x 120 cm x 180 cm and you have 10 boxes. Step 1: convert to meters, 2.5 m x 1.2 m x 1.8 m. Step 2: multiply, 2.5 x 1.2 = 3.0, then 3.0 x 1.8 = 5.4 CBM per box. Step 3: multiply by quantity, 5.4 x 10 = 54 CBM total. At $120 per CBM the freight estimate is 54 x 120 = $6,480.
Where this comes in handy
Importers compare sea freight quotes, movers estimate truck space for a house move, warehouse managers plan pallet positions, and online sellers check whether air or sea shipping is cheaper. CBM is the common language of the whole logistics chain, from a single parcel to a full container.
Mistakes people often make
- Mixing centimeters and meters in the same calculation. Pick one unit and convert everything first.
- Measuring the product instead of the packed box. The freight company charges for the box.
- Forgetting the quantity multiplier. One box at 5.4 CBM is very different from ten boxes at 54 CBM.
What this number does not tell you
CBM is the space your cargo takes up, but the final bill may also involve chargeable weight, which compares actual weight against dimensional weight and charges the higher of the two. Very dense cargo can cost more than its CBM suggests, and port fees, customs, and fuel surcharges sit on top. Treat CBM as the starting point of the quote, not the whole invoice.
Shipping odd-shaped cargo? The cylinder volume calculator handles drums and rolls, the volume of a sphere calculator covers round tanks, and the cone volume calculator works for pointed hoppers.