Density Calculations

Freight class is just one of the variables in calculating an LTL freight rate.  However, it is probably the most misunderstood aspect of LTL rating.  We’ll talk about freight class and the role that density calculations play in determining freight class in this blog.

The National Motor Freight Classification (NMFC) determines class by using four characteristics:  Stowability (the ability of the freight to be stowed in relation to other items), handling (how easy it is to maneuver the freight), liability (value of product), and density.

Dictionary.com defines density as mass per unit volume.  In LTL freight, that definition translates to PCF (pounds per cubic foot).  So, you ask what does that have to do with class and better yet why does that affect my freight? Calculating density accurately tells a carrier how much space your shipment will occupy in the trailer.  The more dense your freight, the lower the class, and the lower the class the lower your rate will be. The less dense your freight is and the opposite will occur resulting in higher rates.

The next time you are trying to determine class, start with calculating your density as it will likely play a role in your class and essentially your rate.  You can use the density calculator on our website under the resources tab if you are unsure of how to calculate your density in pounds per cubic foot.

How to manually calculate density:

Details:

Weight: 2,000 pounds
Dimensions: Standard 48”x48”x48”

Multiply your dimensions together and divide them by 1,728 (1,728 is the total number of inches in a cubic foot).

Ex. 48”x48”x48”=110,592cu”/1,728 = 64cu'

Then take your total weight and divide it by the cubic feet to calculate your PCF:

2,000 pounds/64cu'=31.25 PCF
A density, in  PCF, of 31.25 would calculate out to class 60.

The next time you are trying to determine class, start with calculating your density as it will likely play a role in your class and essentially your rate.  You can use the density calculator on our website under the resources tab if you are unsure of how to calculate your density in pounds per cubic foot.


Michael Catton, 
Operations & Inside Sales Manager

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