Determining Freight Class

The National Motor Freight Classification is a standard which was introduced by the National Motor Freight Association in the USA. Freight class is used to determine pricing by carriers. Note that this freight class standard is only applicable to shipments destined to the USA, originating from the USA or intra-USA shipments. 

While Canadian domestic shipments do not use the freight class standard, pricing will usually be based on freight density per unit of weight.

Freight class is determined by the following details:

  • Density: the trailer space that the freight will take up and its weight
  • Stowability: how the freight can be stowed. Dangerous goods and freight with heavier weights are typically assigned a higher freight class.
  • Liability: Freight that could be damaged, or is considered to be perishable will be designated a higher freight class.
  • Handling: the degree of handling required for the freight. Generally the higher the degree of handling, the higher the freight class.

Now before the freight class can be determined, we need to calculate the density of our freight. Freight density is calculated as follows:

[(Height x Length x Width)/1728] / Weight (lbs)

Important to note that in order for this calculation to work, the dimensions must be in inches, and the weight must be in pounds. 

Once you have determined your freight density, you can use the table below to give you an idea of what the freight class will be. Remember that the freight class will also be impacted by the stowability, liability, and handling mentioned above.

If you need help determining what freight class your shipment falls into, our shipping experts are always ready to help!

Freight density (in lbs per cubic foot)Freight Class
Less than 1400
Between 1 and 2300
Between 2 and 4250
Between 4 and 6175
Between 6 and 8125
Between 8 and 10100
Between 10 and 1292.5
Between 12 and 1585
Between 15 and 22.570
Between 22.5 and 3065
More than 3060

The information in the table presented above was obtained from the National Motor Freight Traffic Association (NMFTA).

ExampleLet’s assume that there is a skid with the dimensions 48″ (height) x 48″ (length) x 50″ (height) and weighs 250 lbs.  If we wanted to calculate the freight density, we would perform the following calculation:

[(48" x 48" x 50") / 1728]/ 500 lbs = 7.5

Based on this calculation, we would recommend that this skid be assigned to freight class 125 seeing that the freight’s density falls between 6 and 8.