How to Calculate Freight Class

Here is the best rule of thumb that we can use for checking freight class. It will not always be accurate but will help determine if they need to raise a red flag.

A Shipment's Density is one of the factors that can determine the freight rate. The total weight of the shipment is divided by the total cubic feet to determine the density.

Step 1. Multiply the three measurements of the freight (height x width x depth). The result is the total cubic inches of the shipment.

Step 2. Divide the total cubic inches by 1,728 (the number of cubic inches in a cubic foot). The result is the cubic feet of the shipment.

Step 4. Divide the weight (in pounds) of the shipment by the total cubic feet. The result is the pounds per cubic foot, ie., density of the shipment.

For example, if the skid weighs 500 pounds with dimensions of 42 inches x 48 inches x 48 inches:

  1. Multiply 42" x 48" x 48" = 96,768 cubic inches
  2. Divide 96,768 by 1,728 = 56 cubic feet
  3. Divide 500 pounds by 56 cubic feet = 8.9 pounds per cubic feet (PCF), ie, density of shipment



Less than 1


1 but less than 2


2 but less than 4


4 but less than 6


6 but less than 8


8 but less than 10


10 but less than 12


12 but less than 15


15 or greater