What Is a CBM Calculator?
A CBM calculator computes the cubic meter (CBM) volume of cartons or packages for shipping and freight. CBM is the standard measure carriers use to price and plan cargo, and it determines volumetric (dimensional) weight, which can affect your shipping cost more than actual weight. Enter the dimensions and quantity of your cartons, and the calculator returns the per-carton CBM, total CBM, and volumetric weight.
How to Use the CBM Calculator
- Enter carton length, width, and height.
- Enter the number of cartons.
- Calculate — see CBM per carton, total CBM, and volumetric weight.
The CBM Formula
CBM = Length (m) × Width (m) × Height (m)
For multiple cartons, multiply by the quantity. For example, a carton 0.5 m × 0.4 m × 0.3 m has a CBM of 0.06; 100 such cartons total 6 CBM. If dimensions are in centimeters, divide each by 100 first, or divide the cm³ result by 1,000,000.
Volumetric (Dimensional) Weight
Carriers charge by whichever is greater: actual weight or volumetric weight. A common conversion for sea freight uses 1 CBM ≈ 1,000 kg, while air freight often uses a divisor (such as CBM × 167 kg). Light but bulky shipments are usually billed on volume.
Container Capacity Guide
| Container | Approx Usable CBM |
|---|---|
| 20 ft standard | ~28–33 CBM |
| 40 ft standard | ~58–67 CBM |
| 40 ft high cube | ~68–76 CBM |
Why CBM Matters
- Freight pricing: ocean and air freight are quoted by CBM or volumetric weight.
- Container planning: CBM tells you how many cartons fit.
- Cost control: optimizing packaging reduces wasted space and cost.
Frequently Asked Questions
How do you calculate CBM?
Multiply length × width × height in meters for one carton, then multiply by the quantity. The result is the total cubic meters of your shipment.
How do I convert cm to CBM?
Multiply the dimensions in centimeters, then divide by 1,000,000 (since there are 1,000,000 cubic centimeters in a cubic meter).
What is volumetric weight?
Volumetric or dimensional weight reflects how much space a shipment occupies. Carriers bill the greater of actual weight and volumetric weight, so bulky light cargo is charged on volume.
How many CBM fit in a container?
A 20 ft container holds roughly 28–33 usable CBM and a 40 ft container around 58–67 CBM, depending on packing efficiency.
Is this CBM calculator free?
Yes — it is completely free, requires no signup, and gives CBM and volumetric weight.