CBM Calculator
Convert carton dimensions to cubic meters, in centimeters or inches, with per-carton and total volume for the whole shipment.
Why freight is quoted in cubic meters
A cubic meter is the standard unit of sold space in ocean and air freight. For less-than-container load shipments a forwarder is effectively renting you a share of a container, and that share is measured in CBM. The same logic drives air freight, where volume is converted into a chargeable weight rather than billed directly, but the underlying question is identical: how much of a finite space does this consignment take up?
The conversion is straightforward once the units line up. Centimeters are the usual working unit in international freight, and dividing the product of three centimeter dimensions by one million gives cubic meters. Shippers working from imperial carton specs need the 2.54 conversion first, which is where the arithmetic most often goes wrong.
Worked example
A carton measuring 120 × 100 × 90 cm.
120 × 100 × 90 = 1,080,000 cm³ ÷ 1,000,000 = 1.08 CBM per carton.
Four of them: 4.32 CBM total.
The same exercise from imperial: a 48 × 40 × 48 inch pallet converts to 121.92 × 101.6 × 121.92 cm, which is 1.510 CBM.
Common mistake
Dividing centimeter dimensions by 1,000 instead of 1,000,000. There are 100 centimeters in a meter, so a cubic meter holds 100³ = 1,000,000 cubic centimeters. Using 1,000 overstates volume by a factor of a thousand, which is obvious on one carton and easy to miss inside a spreadsheet.
Keep going
- CBM prices ocean freight, but air and parcel price on dimensional weight instead; the DIM calculator applies that volumetric rule to the same cartons. Dimensional Weight Calculator
- CBM is volume alone; adding weight gives density, which is what LTL classification turns on. Freight Density Calculator
Frequently Asked Questions
What is CBM in shipping?
CBM is cubic meters — the volume a shipment occupies. Ocean and air freight forwarders quote against it because a container or aircraft hold runs out of space before it runs out of weight allowance for most cargo. One CBM is a cube one meter on each side.
How do I calculate CBM?
Multiply length × width × height in meters. Working in centimeters, multiply the three dimensions and divide by 1,000,000. A carton 120 × 100 × 90 cm is 1,080,000 cm³ ÷ 1,000,000 = 1.08 CBM.
How do I get CBM from inches?
Convert each dimension to centimeters first by multiplying by 2.54, then divide the product by 1,000,000. This calculator does it for you when you switch the unit selector to inches, which is useful when cartons are specified in imperial but the forwarder quotes in CBM.
How many CBM fit in a shipping container?
Usable volume is always less than internal volume because cartons do not tessellate perfectly and pallets waste height. Forwarders work to loadability rather than raw capacity, so treat a container's stated internal CBM as a ceiling you will not reach, and confirm expected loadability with your forwarder.
What is chargeable weight for ocean and air freight?
Ocean LCL is commonly rated on whichever is greater of CBM or metric tons, and air freight converts volume to a chargeable weight using a volumetric divisor. Both follow the same principle as LTL dimensional weight: whichever measure costs the carrier more is the one you pay on.
Related Calculators
- Dimensional Weight Calculator — Dimensions & Weight
- Chargeable Weight Calculator — Dimensions & Weight
- Freight Class Calculator — Freight Classification
- Freight Density Calculator — Freight Classification