CBM & Shipping Volume Calculator
Calculate cubic meters, volumetric weight, and how many containers your shipment needs.
Length
Width
Height
Total Volume
0.072 CBM per carton
Carriers charge whichever is greater: actual weight or volumetric weight.
CBM — cubic meters — is the unit that decides what your freight actually costs, and misunderstanding it is one of the most expensive routine mistakes in importing. Shipping companies do not simply charge by weight. They charge by whichever is greater: the actual weight or the volumetric weight, because a container filled with pillows fills the space long before it reaches the truck's weight limit. This calculator gives you the volume of your cartons, the total CBM of your shipment, and the chargeable weight the carrier will use to invoice you. Running these numbers before you commit to a supplier's carton design is the difference between an accurate margin and a surprise that eats it.
How the calculator works
Enter the length, width, and height of one carton along with the number of cartons. The calculator computes the volume of a single carton in cubic meters, multiplies by the quantity for total CBM, and then applies the standard volumetric divisor to give you the volumetric weight. Compare that against your actual weight: whichever is higher is what you pay for. That comparison is the entire point of the exercise, and it is where most first-time importers get caught.
The formula
CBM per carton = (L × W × H) ÷ 1,000,000 [dimensions in cm]
Total CBM = CBM per carton × Number of cartons
Volumetric weight (air) = CBM × 167 kg
Volumetric weight (sea) = CBM × 1,000 kg
Chargeable weight = greater of (actual weight, volumetric weight)The divisors look arbitrary but encode a density assumption. Air freight uses roughly 167 kg per CBM, meaning anything lighter than that per cubic meter gets charged on volume instead of weight. Sea freight uses 1,000 kg per CBM — one metric ton. So a shipment of 2 CBM weighing 400 kg is charged as 400 kg by sea but as 334 kg volumetric by air, and if it weighed only 200 kg, air would charge you for 334 kg regardless. Light bulky goods are punished by air freight specifically because of this ratio.
What to know about shipping volume
- 1Carton dimensions matter more than product dimensions. A supplier who packs loosely can add 30% to your CBM without adding a single unit, and you pay for the air inside the box. Asking for a carton spec sheet before production, and negotiating tighter packing, is one of the cheapest cost reductions available in importing.
- 2Know the container ceilings. A 20-foot container holds roughly 28 CBM usable, a 40-foot about 58 CBM, and a 40-foot high cube around 68 CBM. If your shipment sits at 30 CBM you are paying for a 40-foot container while filling half of it — either increase the order or consolidate with another shipment.
- 3LCL is not always cheaper than FCL. Less-than-container-load charges per CBM plus fixed port and handling fees at both ends. Past roughly 15 CBM, a full container often costs less in total and moves faster, since LCL cargo waits for consolidation and gets deconsolidated on arrival.
- 4Air freight punishes bulk brutally. At 167 kg per CBM, light products — apparel, foam, packaging — are almost always charged on volume. If your goods are bulky and not urgent, sea freight is typically 5–10 times cheaper for the same shipment.
- 5Measure the carton as it ships, including any bulges. Carriers measure the outermost points, so an overstuffed box that bows measures larger than its nominal spec. On a large shipment, a centimeter of bulge per carton is enough to move you into a higher billing bracket.
Frequently asked questions
What exactly is CBM?
CBM stands for cubic meter and measures the volume your cargo occupies — length times width times height. It is the standard unit for pricing sea freight and for calculating volumetric weight in air freight. One CBM is a cube one meter on each side. Since dimensions are usually recorded in centimeters, you divide the product by 1,000,000 to convert into cubic meters.
Why am I charged for volumetric weight instead of actual weight?
Because space is the constraint, not weight. An aircraft or container fills up with lightweight cargo long before it reaches its weight limit, so charging purely by weight would mean carriers lose money on every bulky shipment. Volumetric weight prices the space you consume. You pay whichever measure is higher, which for light, bulky goods is nearly always the volumetric figure.
How much fits in a 20-foot or 40-foot container?
A 20-foot container has about 33 CBM of internal capacity but roughly 28 CBM of usable space once real-world stacking and pallet gaps are accounted for. A 40-foot gives about 58 CBM usable, and a 40-foot high cube about 68 CBM. Always plan against the usable figure, not the theoretical internal volume, because you will never achieve perfect packing.
Should I ship LCL or FCL?
LCL makes sense below roughly 15 CBM, since you only pay for the space you use. Above that, run both quotes — FCL frequently costs less in total despite booking the whole container, because LCL adds fixed consolidation, handling, and destination charges that scale poorly. FCL is also faster and involves less handling, which means less damage risk.
How do I reduce my CBM without reducing the order?
Redesign the packaging. Nesting products, removing unnecessary void fill, using right-sized cartons instead of standard ones, and shipping items disassembled all cut volume substantially. Suppliers default to whatever carton they already stock, which is rarely optimal for your product. A 15% reduction in CBM is a 15% reduction in freight cost on every shipment thereafter, which compounds quickly across a year.