What is CBM and How it is Calculated?

CBM, an abbreviation of Cubic Meters, is one of the most commonly used units of measurement of the volume of shipment, globally. The shipment can be air freight or ocean freight. And as the volume of the shipment ultimately decides its freight cost, CBM measurement is an important process in the global trade business.

Determining the right size of container for your goods to be delivered can help you manage & control your shipment costs better. For this, it’s important to understand the concept of CBM and how many CBM can be stored in a container.

Calculation of CBM in Shipping

Calculating CBM for a product is quite simple. All you need to do is just pack it into a cubical/cuboidal box and map the dimensions correctly. Now, measure the box’s length, width and height in meters. It is important to note here that the measurement should be taken only in meters. If taken in any other unit, it is advisable to convert it into meters first. After you have all three measurements, multiply them and you’ll get the CBM value of your package.

For instance, if, Width = X m Length = Y m Height = Z m Then, the CBM of this package will be X m X Y m X Z m = XYZ CBM.

The calculation of CBM with this formula only takes into account the dimensions or volume of your shipment and not its weight. There are many shipping companies that use the concept of CBM Chargeable Weight which also considers the weight of the shipment while deciding the freight cost. We will be discussing this concept in detail below.

Methods of Calculating CBM

A shipment may not always come packed in regular shapes such as a cube or a cuboid. It can be of different shapes and sizes depending on the type of product. It can be cylindrical or have an irregular shape. There are different methods for calculating CBM for such packages.

Calculate the CBM of a cube or a cuboid cargo is the easiest.

Measuring CBM of a Cube or Cuboid

The formula for measuring the CBM of a cube or cuboid remains the same i.e. multiplying the width, length, and height (w x l X h) of the container. For a cube, all three dimensions would be equal.

Measuring CBM of a Cylindrical Package

To measure the CBM of a cylindrical package, you will have to stand the container upright on one of its circular faces and measure its height. Then, measure the radius of the container. Use this formula to get the CBM of the shipment: CBM = π X height X radius2 The value of π is generally taken as 3.14.

Measuring CBM of an Irregularly-shaped Package

The CBM of an irregularly-shaped package is calculated by multiplying its longest width, longest length, and longest height. Especially for containers with irregular shapes, the freight charges calculated with CBM are compared with freight charges calculated using volumetric weight. And whichever is higher, is charged from the shipper.

CBM Rates and Factors Influencing It

We hope now you are clear about the various methods of calculating CBM for different packages. Now, let’s find out how freight carriers compute the CBM rate to be charged from the shippers/customers? There are a lot of other factors that are taken into consideration while arriving at the CBM rate for a container to be shipped that include the port charges, the type of shipment, the basic freight from origin to destination, Currency Adjustment Factor (CAF), etc.

Port Charges

The port charges may be different for different ports. These charges are paid to the port authorities for using their various facilities and equipment for loading and offloading of shipment.

Type of Shipment

A shipment is generally classified as dry or frozen. Frozen shipment requires a refrigerated container to transport it. Therefore, its costs substantially higher than the shipment of a dry container.

Currency Adjustment Factor or CAF

This is a surcharge that is passed on to the shipper/customer to make up for fluctuations in the currency rates between different countries or markets.

Sometimes, a shipper may get preferential CBM rates from the ocean carrier depending on the volume of shipments and the regularity of business with them.

Calculation of CBM Chargeable Weight

While shipping goods, it is possible that a relatively light package takes up more space than a heavier yet smaller one. In such a scenario, if the shipping company levies the charges on both the packages based on their weight, the bigger package would not be profitable to ship, since it occupies more space but weighs less.

To solve this problem, the concept of CBM chargeable weight was introduced. To understand chargeable weight better, first, let’s understand the terms used with it:

a. Actual Weight: The gross weight of the package that is to be shipped.

b. Dimensional/ Volumetric Weight: Multiply the CBM value of the package with the Dimensional Weight Factor, or “DIM factor” based on the mode of transportation, to get the Dimensional or Volumetric Weight of the package.

DIM Factors for different modes of Shipping:

• Ocean Freight: 1:1000
• Air Freight: 1:6000
• Express Freight/Courier: 1:5000
• Truck LTL: 1:3000

Of the two, whichever is higher accounts for the chargeable weight by the carrier.

How to Calculate Ocean Freight LCL (Less Container Load) Shipment Rate/Cost Using CBM

For calculating the shipment cost of LCLS, there are two factors that are considered – the CBM and the weight. As mentioned earlier, CBM for LCL shipments sent via ocean freight, the estimation factor for calculating the volumetric weight is generally 1:1000 i.e. one cubic meter is equal to about 1000 kilograms. Let’s understand this with an example.

Suppose that a freight forwarder is charging $15 per CBM or ton. Now, there can be two different situations that can arise:

a. When CBM is higher than weight Let’s assume the dimensions of the package are 5m in length, 5m in height, and 5m in width while its weight is 500kgs. Then the CBM would be: 555 = 125 CBM In this case, the weight is less than 1 ton and CBM is greater than the weight of the shipment. Therefore, the basis for the calculation of freight cost shall be, Freight Cost: 125*15 = $1875

b. When Weight is higher than CBM Let’s assume the dimensions of the package to be 2m in length, 1m in height, and 3m in width while it weighs 7 tons. The CBM of the package shall be: 213 = 6 CBM

Since the weight of the container exceeds the CBM value, the weight will be considered as the basis for the calculation of freight cost. Freight Cost = 7*15 = $105

How to calculate CBM for air shipment/ air freight?

In an air shipment, the CBM calculation remains the same, but the freight is charged on actual weight or volumetric weight (after multiplying CBM by the DIM factor) — whichever is higher. The DIM factor generally used in Air freight is 1:6000 i.e. one cubic meter is equal to about 6000 kilograms.

Let’s understand this better with an example. Let’s assume the dimensions of a package to be 2m in length, 2m in height, and 2m in width while its actual weight is 500kgs. And the freight forwarder has given you a quote of $1.5 per volume weight or actual weight whichever is higher.

Now, CBM of the package: 222 = 8 CBM Volumetric weight for an air cargo = 8/0.006 = 1333.33 KGs

Now, since the volume weight is higher than the gross weight, hence, the former will be considered for calculating air freight cost, i.e 1.5*1333 = $1999.5

Calculating CBM in Garments

The garments are exported in cartons that are smartly designed not to take up a lot of space and can easily be stacked on top of each other. Once they are packed in standard cartons, calculating their CBM is not difficult at all. The formula for measuring the total CBM for your garments container shall be:

Length of the carton (m) X Breadth of the carton (m) X Height of the carton (m) X Number of cartons in the container = Total CBM of the container

(Suggested Read: What is NVOCC and Why They are Important in Global Logistics?)